*

COMPUTERISED ELECTRO-MECHANICAL

CONTROL OF THE UWS ASTRONOMICAL

TELESCOPE AND THE INTEGRATION OF A

MULTI-TASKING TELEVISION SYSTEM

by

FRANK WILLIAM BIRD BSc BTeach

A Thesis submitted for the Degree of Master of Science (Hons)

at the University of Western Sydney, May 2005.

DEDICATION

To my lovely wife Treve who patiently entered every (well almost) keystroke in this

Thesis as I clumsily dictated the content. Her willingness to help, and the many late

nights at the keyboard are very much appreciated.

i

ACKNOWLEDGEMENTS

I would like to thank all those concerned in making this Thesis possible. In particular I

would like to thank Dr. Graeme White who invited me to be involved in the UWS

Telescope project and gave me great support and assistance during the project. Thanks

also go to my co supervisor Dr Paul Jones and to my supervisor in the latter stages of the

project Dr Ragbir Bhathal. I thank UWS Nepean for providing a HECS exemption

scholarship and other resources to enable me to complete this Thesis. Finally, I thank

my wife for enduring the upheavals and changes household routine which an

undertaking such as this inevitably inflicts.

ii

STATEMENT OF AUTHENTICATION

I declare that to the best of my knowledge, the work described in this Thesis is original,

except as acknowledged in the text, and that the material has not been submitted, either

in whole or in part, for a Degree at UWS or any other University.

FRANK W BIRD

April 2005

iii

TABLE OF CONTENTS

Page

CHAPTER 1. - Introduction

1.1 Purpose of this Thesis 1

1.2 A brief history of Astronomical Telescopes

1.2.1 Early instrumentation 2

1.2.2 Scientific use of Telescopes and the effects of

aberrations 4

1.2.3 Use of mirrors 6

1.2.4 Limitations and developments 8

1.2.5 The UWS Telescope 9

1.2.6 Telescope mountings 10

1.2.7 Equatorial mounts 13

1.2.8 Alt-Azimuth mount 14

1.2.9 Adding a layer of complication to a simple problem

of telescope mounting 15

1.2.10 Computer control 18

CHAPTER 2. - Mechanical Resonant Frequencies

2.1 Resonant frequencies 20

2.2 Method used 20

CHAPTER 3. - Aligning the Equatorial Head

3.1 Criterion for long exposure 22

3.2 Alignment method 22

3.3 Altitude adjustment 24

3.4 Azimuth adjustment 26

iv

CHAPTER 4. - Initial Tracking and Slewing Control System

4.1 Tracking and slewing system 28

CHAPTER 5. - The Video System at the UWS Observatory

5.1 Tasks 31

5.2 Onsite education 31

5.3 Remote viewing 37

5.4 Remote science 38

5.5 Research 39

5.6 Public viewing 40

5.7 A note on Gamma correction 44

5.8 Star-trak 47

5.9 Precautionary note 48

CHAPTER 6. - Engineering Approaches to Telescope Automation

6.1 Go-to 50

6.2 Stepper motor benefits 52

6.3 Stepper motor drawbacks 53

6.4 Brush servo benefits 53

6.5 Brush servo drawbacks 54

6.6 Brushless servo benefits 54

6.7 Brushless servo drawbacks 55

CHAPTER 7. - The Control System at UWS

7.1 Chosen system 56

7.2 Making things easy 58

7.3 Safety 59

v

CHAPTER 8. - A Pointing Model

8.1 Options 62

8.2 Observation data 63

8.3 Assessment of pointing model scatter plots 95

CHAPTER 9. – Conclusions and future work

9.1 Current performance 96

9.2 Future work 96

9.2.1 Video System 96

9.2.2 Robotics 97

REFERENCES 98

APPENDIX A - EXTRACTS FROM ACE MANUAL 99

vi

LIST OF TABLES

page

Table 1. Spread sheet layout of HA prime unit and correction 87

Table 2. Spread sheet layout of DEC prime unit and correction 94

vii

LIST OF FIGURES AND ILLUSTRATIONS

page

1. The first known use of instruments in astronomy 2

2. A wood cut of Hans Lippershey taken from Pierre Borel’s 3

De Vero Telescope Inventore, 1655.

3. Galilao demonstrating his first telescope 4

4. Spherical aberrations 5

5. Longitudinal chromatic aberration 5

6. Lateral chromatic aberration 6

7. George Dollond (1774 – 1852) 7

8. The main components of the Great Paris Refractor 8

9. The f10 UWS observatory 9

10. Altitude azimuth and equatorial mounts 11

11. The Great Dorpat Refractor 12

12. Schneider’s Helioscope 13

13. Relative amplitudes of the telescopes resonant frequencies 21

14. Eliminating non-linear scan error using an electronic pattern

generator 23

15. Elevation adjustments and resulting error 25

15.1 Increments in Azimuth and the resulting error 26

16. VFO Circuit diagram 29

16.1 Original system hand paddle 30

17. Video patch panel 32

18. Moon Cam mounted on the side of the main frame 35

19. Rear view of the UHF modulators 36

20. YH438C Q video switcher (ACE smart dome control unit below) 39

21. Video system schematic 43

22. Gamma correction curves 45

22.1 1/3 inch CCD camera with adjustable gamma 46

viii

23. Outer-rotor construction of the Dinaserve motors 56

24. Output torque versus speed of the DM/DR series motors 57

25. U-matic idler wheel coupled to encoder below 59

26. Control desk with CCTV monitor 61

27. Scatter plot of HA prime unit versus correction 88

28. Scatter plot of DEC prime unit versus correction 94

ix

ABSTRACT

Obtaining a very high level of precision and sophistication in automated computer

control is now available inexpensively from a variety of hardware and software sources.

Applying this automated technology to an astronomical telescope broadens the scope of

applications of the instrument, particularly in areas such as photo electrics, CCD

imaging and remote control.

The ultimate design goal of the UWS telescope was that of full roboticism, giving

access of the facility to off campus clients both in Australia and overseas. The first

phase toward full robotic control is automation of the required optical and mechanical

parameters, providing precision targeting and object tracking.

This Thesis describes the mechanical aspects of the UWS Telescope and the procedures

and equipment involved in its automation, including the drive system, electro

mechanical design and associated computer hardware and software. Sample

performance test data shows that using a high percentage of inexpensive proprietary

robotics components, a very sophisticated and accurate measuring device can be

produced.

x

1

CHAPTER 1 - INTRODUCTION

1.1 PURPOSE OF THESIS

This thesis describes and discusses the installation, testing and commissioning of the

control system and TV camera systems of the 24 inch, f/10 Ritchy-Chretien telescope of

the UWS Observatory at the University of Western Sydney. The intention at the

University of Western Sydney (UWS) was to firstly put the telescope under computer

control, secondly to have the telescope fitted with various cameras which could be used

for teaching and remote viewing (see video system chapter 6) and thirdly to have the

telescope controlled robotically over the internet by a distant observer.

The telescope at UWS was designed to carry out two principal roles for the centre of

astronomy. The first one was to provide a research tool for its undergraduate and early

level post graduate students. The second role was to act as a teaching observatory for

the University, and to allow the university to interact with the public and with the school

sector of Western Sydney. A principal design parameter of the facility was to put TV

images into various places around the building and hopefully eventually over the

internet.

As such, it is appropriate to start this thesis with a brief historical review of the

instruments used in astronomy, their mounting systems, their control systems, and how

this knowledge was applied to the instrumentation systems at the UWS Observatory.

2

1.2 A BRIEF HISTORY OF ASTRONOMICAL TELESCOPES.

1.2.1 Early instrumentation.

Historically, astronomy became a science possibly as early as 3000 years BC. The

earliest scientific instruments that are recorded, and that are in collections, consist of

plumb bob lines which were used for sighting from one observer to the other. These

were used for the practical application of astronomy, namely for navigation, and for

surveying for the determination of land etc. after flood. The earliest of these dates back

to Egyptian times

.

fig 1. The first known use of instruments in astronomy. (Reproduced from.King 1955).

The first of the instruments that attempted to measure the elevation of an object in the

sky came about in the Greek times and one particular instrument called Ptolemy’s Rule,

which used the combination of two axes of rotation, the vertical axis and the horizontal

axis. This instrument allowed the measurement of both the azimuth and the elevation of

the object . The telescope itself as we know it was invented in 1608 by a Dutch optician

named Hans Lippershey.

3

.

fig 2. A woodcut of Hans Lippershey. ( Pierre Borel’s De Vero Telescopii

Inventore,1655 .Reproduced from King 1955)

Lippershey patented the concept, although it is reputed that it was actually invented

sometime before that, in Holland, as being a mechanism for measuring the strength of an

army. In other words it was patented as a military device.

4

fig 3. Galileo demonstrating his first telescope (American Museum of Natural History.

Reproduced from King 1955)

1.2.2 Scientific use of telescopes and the effects of aberrations

The first scientific use of the telescope was by Galileo in 1610 and his observations are

well recorded as they are the basis of the dispute between the Catholic Church, the Pope

and Galileo which resulted in Galileo being immortalised.

The telescope used by Galileo was a very simple device consisting of a tube with 2

lenses attached, one being a convex lens which converged the light from a distant object

to an image and the second, being a negative lens which then translated that image back

to the retina of the eye. This optical configuration was by modern standards rather

unsatisfactory, although it can still be found in very cheap binoculars and plastic toy

binoculars found in Department Stores. The Galilean optical system is still used today

in instruments such as opera glasses. The Galilean telescope as it became known has

two fundamental limitations. The first one is to do with the eye piece lens which was

5

concave. This lens limited the magnification of the telescope, and also very severely

limited the field of view. (The two working in tandem, the greater the magnification, the

smaller the field of view). This was a very severe practical limitation. It did however

have one very great advantage and that was it left the image as seen through the

telescope erect i.e. Images pointing in the same direction as the object. This type of

telescope was ideally suited for terrestrial viewing but not necessarily for astronomical

viewing.

The eye piece was eventually replaced by a positive lens which eliminated the

difficulty of field of view and allowed magnifications to go much higher, but did in fact

turn the image upside down which is not a problem scientifically but meant that this

type of telescope was no longer suited for terrestrial viewing. The other difficulty with

the Galilean telescope was the simple convex objective lens. This lens suffered from the

standard lens aberrations, the principal one being spherical aberration and the other of

concern being chromatic aberration.

fig 4. Spherical aberration.

fig 5. Longitudinal chromatic aberration

6

fig 6. Lateral chromatic aberration

Those two are highlighted because they are in fact the most important. The way to

eliminate these is to increase the focal ratio, as all of these scale as the f number, indeed

some of them scale as the f number squared. Going to larger f numbers meant that the

telescope became rather unwieldy, very long and difficult to keep stable and point in the

right direction. Combining that with a very narrow field of view meant that trying to

acquire the object in the sky was very difficult indeed. The latter problem of spherical

and chromatic aberration was solved by George Dollond (McConnell 1992), who

discovered and eventually manufactured a lens that would violate the rule laid down by

no other than Isaac Newton.

1.2.3 Use of mirrors.

Newton’s idea was that dispersive power and refractive index of glass were the same

and they could not be separated, and therefore, if a lens was made of sharper curvature

the dispersive power of the lens would only be enhanced. This in fact is not true, and

Dollond showed that a combination of curvature and dispersive power and refractive

index could be put together in such a way that the dispersive power could be turned back

on itself by a second lens without eliminating the curvature, so the net result was that the

two lenses working together would create an image free from chromatic and spherical

aberration. This lens was called the achromatic lens and because there were two of them

it was called the achromatic doublet.

7

fig 7. George Dollond 1774-1852.(Reproduced from King 1955).

However, probably the greater step forward in optics in terms of astronomical

telescopes did in fact come from Isaac Newton who believed that the aberrations of a

lens could not be eliminated and so decided to remove lenses from the objective

component of the telescope. Newton’s contribution was to use a curved mirror, a

concave mirror, to bring light to a focus where it could be then magnified by a series of

smaller lenses. This was a key stroke in the development of astronomical telescopes.

The next step to follow from that was the placement of a second mirror into the system

which turned the light back, and put the eyepiece at the rear of the telescope, a more

acceptable place for it. Selecting the correct configuration even returns the orientation of

the image to normal. That configuration, called Gregorian, is no longer used in

astronomical telescopes but it was at one stage quite fashionable amongst small

terrestrial type telescopes.

The other key development in the telescope was the introduction of glass mirrors. This

came about towards the end of the 1800’s when it was discovered that mirrors could be

produced via the deposition of silver onto glass. Glass is a very hard substrate, it can be

worked and shaped with great precision and the thin layer of silver on the top surface

made a perfectly good reflecting device. This technology was invented in the 1860’s

and was adopted by most of the great telescopes of the first half of the last century

including the 60 inch telescope at Mount Wilson, the 100 inch telescope at Mount

8

Wilson and later the 200 inch telescope at Mount Palomar. In passing, it can be noted

that the technology for depositing silver onto glass was available at the time of the

purchase of the Great Melbourne Telescope. It is considered by many historians that the

failure of the Great Melbourne Telescope as a scientific instrument was partly due to the

lack of adventuresome engineering in the manufacture and design where the traditional

specula metal mirror was adopted in preference to the emerging silver on glass

technology. Subsequent attempts to clean and re-polish the specula metal mirror proved

to be unsuccessful and as a consequence the instrument was never as powerful as the

designers had hoped it would be.

1.2.4 LIMITATIONS AND DEVELOPMENTS

The refracting telescope also evolved but reached a practical limit in its size towards the

end of the 19th century. The largest refracting telescope ever built was a 50 inch lens

which was mounted in Paris for the Great Fair of 1900 and was subsequently dismantled

and placed into a box and never used.

fig 8. The main components of the Great Paris Refractor.(Reproduced from King 1955)

The second largest built was the 40 inch telescope at Yerkes observatory in Wisconson,

USA and the third largest built was the 36 inch refracting telescope built at Lick

Observatory on Mount Hamilton in California. These telescopes are nowadays still in

operation but are very much historic in their nature but still used in scientific work.

The reflecting telescope however has developed even further and modern instruments

such as the Keck 1 and 2 and the European Southern Observatory’s very large telescope

called VLT are continuations of the development of the technology. For these very

large telescopes the mirrors are segmented into smaller sub mirrors and aligned with

piezo electric adaptors. The entire telescope mirror is kept into place by laser

holography and the shape of the mirrors themselves are adjusted to allow for

9

atmospheric changes above the telescope using techniques known as adaptive optics.

(Max 2003).

fig 9. The UWS OBSERVATORY at the University of Western Sydney,Nepean

1.2.5 THE UWS TELECSOPE

The telescope of the Nepean Observatory at the University of Western Sydney is a much

smaller version and much lower technology than the ones just referred to. The telescope

at UWS is a 24 inch Cassegrain telescope built along the lines of the Ritchey-Chretien

optical system.

This design criteria were made by Dr Graeme White who developed the original concept

of the UWS Observatory and supervised the construction, as well as the design,

construction and installation of the telescope itself.

This particular optical design using hyperbolic mirrors eliminates many of the

aberrations in the focal plane which cause image distortion such as astigmatism and

spherical aberration, but leaves in the image some image distortion and a small amount

of curved field. Image distortion does not openly destroy the quality of the image as

does the other aberrations, so it is the preferred optical configuration.

10

1.2.6 TELESCOPE MOUNTINGS

Along with the development of the optical telescope comes the development of the

mounting for the telescope.

The fundamental underlying physics and engineering of telescope mountings is that the

telescope must be made to continue to point to the object in the sky with a precision

which is comparable with the ability of the telescope to resolve the object. In early days

the ability of an instrument to resolve an object was limited to the resolving power of the

human eye. It was necessary for instruments without optical aid to have a stability and

pointing accuracy of a few minutes of arc, a minute of arc being the limiting resolution

of the human eye. Early astronomical instruments did not require a high level of

engineering to make them stable for their intended use.

An additional problem for the mounting of astronomical telescopes is that the sky is

continually moving with respect to the telescope. The motion of an object across the

sky is a consequence of the rotation of the earth. This motion is both in altitude and

azimuth simultaneously, with the exception of two sets of places on the earth where the

motion can in fact be simplified to be one axis rotation. These places are the poles and

on the equator. For all other observing places the motion of an object across the sky is a

combination of azimuth and elevation change.

A first order mechanism to eliminate this difficulty is to tilt one of the axis of the

telescope to be parallel with the earth’s axis.

To eliminate the motion of one of these axis throughout the observing session, the

second axis, the one which is not rotating, is pointed towards the celestial pole. This is

the concept of equatorial mounting, where one axis is called the equatorial axis or the

polar axis and the other is called the declination axis.

11

fig 10. Note: Items a, b, and c are altitude azimuth designs and for which simultaneous

motion in both axes is necessary to track the object in the sky. Items d, e, f and g are

equatorial mounts requiring motion in only one axis (Ridpath 1991).

Possibly the most significant development in the equatorial mountings was the Dorpat

refractor built by Fraunhofer. This instrument had two axis but mutually perpendicular

and was also fitted with significant counter weighting to allow for flexure in the axis.

Of great significance was that this telescope, it is believed, was the first time that roller

bearings were ever used. Dorpat was instrumental in their development and used them in

the support mechanism of the polar axis of the refractor.

12

fig 11. The Great Dorpat Refractor (KING 1955)

13

1.2.7 EQUATORIAL MOUNTS

The first equatorially mounted telescope was by Scheiner in the early 1600’s. Tyco

also used equatorially mounted instruments, although they were not telescopes they

were non-optical sighting instruments for his observations. The first equatorial

instruments were by Tyco. The first equatorially mounted telescope was by Scheiner.

fig 12. Schneider’s Helioscope (King 1955)

The mounting on the Dorpat telescope is now known as the German Equatorial Mount.

There are other hybrids of equatorial mounts. Those hybrids being the English

Equatorial Mount, the Fork Equatorial Mount, such as at the twenty four inch telescope

at the UWS Observatory and the Yoke Equatorial Mount. A further system, called the

Horseshoe, is employed at the Anglo Australian Telescope at the Siding Spring

observatory near Coonabarrabran. The difference in these designs allows for different

14

shape telescopes and different latitudes. Some designs are more suited for different

latitudes than others e.g. the Fork telescope is very seldom used at the Equator or near

the Equator where the angle of the Fork is low to the horizon and vibrations are easily

introduced into the system.

1.2.8 ALT-AZIMUTH MOUNT

The simple azimuth telescope mounting used in the very earliest of instruments is still

used today in telescopes and underwent a resurgence of interest with the introduction of

radio telescopes and computers. A single dish radio telescope has a larger beam in the

sky, and as such, the pointing accuracy of these telescopes need not be as accurate as

that for optical telescopes thus relaxing some of the engineering design. In early days

this computing was done by analogue devices, such as the master equatorial on the

Parkes Radio Telescope.

The exception to this has been in the last 20 years during which there has been

resurgence in optical telescopes back to Alt Azimuth. The intrinsic advantage of the Alt

Azimuth is that the mechanical aspects of it are very stable. The weight in an Alt

Azimuth mount is carried on a vertical fork so the instrument can be very stable from

vibration. The disadvantage of the Alt Azimuth mount is that the telescope has to be

driven in both axes simultaneously and at a non-uniform rate. This is quite easily

obtained nowadays with the use of computer controlled systems but it is an additional

complication which is probably unwarranted in relatively small instruments such as the

UWS telescope. An additional complication in large Alt Azimuth telescopes is that the

field of view at the eye piece also rotates with the other two motions. This necessitates a

third mechanical electro system to drive the camera to rotate on the optical axis of the

telescope to compensate for the rotation of the field of view. This means there are 3

systems all of which have to be undertaken very carefully with high level precision

computer equipment.

The first of the big Alt Azimuth optical telescopes was actually the Russian telescope

called the BTA which was built in the Caucausus Mountains in the 1960’s. It was

15

absolutely a pioneering piece of engineering at the time although it seems historically

the telescope has never been a great success, for reasons which may or not have to do

with the Alt Azimuth mounting, but more to do with the optical system.

1.2.9 ADDING A LAYER OF COMPLICATION TO A SIMPLE PROBLEM OF

TELESCOPE MOUNTING.

The equatorial mount is designed to eliminate the rotation of one axis and to give a

uniform rotation on the polar axis as an object is tracked in the sky. This is a theoretical

model. There are additional layers of complication which must be taken into account.

The first of these is the mechanical construction of the instrument itself. The first and

most obvious correction that is necessary is to allow for mechanical flexure in the

telescope due to the influence of gravity. This occurs because the angle of the telescope

relative to the vertical changes as the telescope follows the object across the sky, which

in turn changes the forces due to gravity acting on different parts of the structure. In

practice this is corrected assuming the flexure scales as the cosine of the angle of the

telescope relative to the vertical. If both axes are not perpendicular then additional

corrections need to be built into the tracking system.

As stated above the precision with which the telescope must point at the sky and

maintain that pointing over the duration of the observation is determined by the

resolving power of the telescope. For all telescopes the resolving power (in Radians) is

given by :

Resolving power (Theta, in Radians) =1.22 Wave length (Lamda in Metres)/ Aperture

diameter (d in Metres). θ=λ/d.

For optical telescopes the Lambda can be approximated to 550 nm and this equation

gives - after transformation of units - an angular resolving power of one arc second for

16

a telescope of approximately 100 mm aperture. In practice larger instruments do not

improve the resolving power of the telescope (contrary to the above equation) as the

turbulence of the earth’s atmosphere limits the resolving power to approximately one arc

second. There is considerable debate in the literature about how to improve this

limitation, the simplest one being to take the telescope to a high, clear, stable

atmosphere or indeed, in the limit, place the instrument into space free from the earth’s

atmosphere, such as has been done with the Hubble Space Telescope.

The necessity to keep the optical telescope pointing at a one arc-second precision

necessitates that all mechanical axis be aligned to that precision i.e. the declination axis

needs to be perpendicular to the polar axis to one arc second. This is mechanically

difficult to do and a correction to the declination axis throughout the observation is often

necessary to eliminate the lack of perpendicularity of these two axes. In addition the

polar axis itself must be aligned to the rotation axis of the earth. This must also be done

to the same precision. There are standard techniques for doing this. (See chapter on

Equatorial Alignment)

An additional complication and one which is the major limiting parameter in the

operation of optical telescopes is the refraction of the earth’s atmosphere. The earth’s

atmosphere has a refractive index of approximately one (Allen 1973) but this is

dependant on humidity, temperature and pressure. The atmosphere does in fact refract

light that enters it, and the amount of refraction depends on the angle of incidence into

the atmosphere. Light coming directly from above at the zenith is not refractive,

whereas light coming from angles close to the horizon is refracted upwards by a small

amount. The amount of refraction is not just dependent on the angle to the horizon but

it is also dependent on the temperature and pressure and in particular the humidity and

gaseous content of the atmosphere.

The refraction is also wavelength dependent which means that different coloured

objects, stars with different dominant spectral features, are refracted by differing

amounts. This is a second order effect but still one which needs to be included. The

bottom line is that the refraction is something which works on both the polar axis and

the declination axis, and small adjustments are needed in both these axes as the

17

telescope moves towards the horizon. Also it should be remembered that the refraction

is dependent on atmospheric conditions, so one particular day to the next, or even hour

to hour, the refraction changes and this means the telescope does in fact need to have the

capacity to drive (albeit it small amounts), in declination and to have small changes in

drive speed in the right ascension to correct for these changing parameters.

As well as aligning the pole of the telescope to be parallel with the earth’s axis, the

correct procedure is to align the pole to be parallel to the refracted axis of the pole and

this is again a small correction needed to the mechanical alignment of the telescope .The

elevation of the refracted pole above the horizon depends upon the declination of the

stars being used at that time, so for a complicated and precision instrument, the pole axis

should be adjusted for the declination of the object being observed. This complication is

beyond the mechanical and technical ability of instruments of the size of the system at

the UWS Observatory and therefore corrections need to be made to both axes for the

declination dependence of the elevation of the polar axis. A case can be cited where the

mechanical elevation of the polar axis of the telescope is adjusted for the declination of

the object being observed. The 1.2 m U.K. Schmidt Telescope at Siding Spring

Observatory uses an adjustable pole elevation mechanism. The procedure outlined

earlier does result in polar alignment to the refracted pole.

Thus, in theory, the polar axis allows for one rotation to counteract the rotation of the

earth. In practice both axes need to be adjusted in small angles to allow for effects

which are usually beyond the mechanical construction of most instruments. This is why

the axes must be fitted with precision encoders and precision driving mechanisms to

allow for this change.

The pointing of the telescope is limited again to one arc-second and as it is desirable to

drive the telescope so that the image on the camera is not blurred, it is necessary to have

that precision maintained over the duration of the exposure at better than 1/10th of the

blur size on the image. In theory we do need to have the telescope maintain it pointing

to 1/10th of an arc-second over the duration of the exposure which could be minutes, or

considerably longer. This requires a positive feedback system. This accuracy cannot be

achieved without precision electro-mechanical engineering.

18

One mechanism of retaining this accuracy in telescope pointing is to adopt an automatic

guiding system (or auto-guider) to maintain the instrument in the exact position. The

consequence of using an autoguider is that the telescope no longer needs to track to the

earlier precision but it does need to exhibit smooth tracking with any jerks in its motion

no greater than 1/10 of an arc-second. With smooth guiding and computer controlled

adjustments for errors in the tracking, exposure times of up to one hour can be

maintained.

Some type of automatic guiding system or auto guider is required to maintain the

camera in the exact location. One consequence of this is that the telescope needs to not

only track with the precision of 1/10th of an arc second but it also needs to exhibit

smooth tracking with no jerks in the tracking larger than 1/10th of an arc second. This

brings us back to the step size on the stepping motor.

This stepping size is smaller than the seeing disk on the image – smaller than 1/10th of

an arc second. There is a momentum property in telescope where even though the

telescope is being driven along at 1/3rd arc second per step, the momentum in the

telescope will smooth much of that out.

The design parameters for the UWS telescope called for a stepper size at the motor of

1.8 deg (or 200 steps per turn). The gearbox ratio plus the 9.6: 1 polar disk roller ratio

resulted in a stepper size in the sky of 0.06 arcsec.

1.2.10 COMPUTER CONTROL.

The first serious attempt to automate an astronomical telescope was made in 1955 by

Bart J Bok (Bok, 1955). It was used for relatively uncomplicated photometry work in

the provision of standards for photographic plates (Reddish 1966) and the study of

variable stars (Maran 1967). The aim of this early device was to automate the

photometric process which collected light from a star, amplified it via a photomultiplier

tube and measured it. Several similar systems quickly followed the work of Reddish

and Maran and in the early 80’s Martin and Hartly extended the concept by remotely

controlling a computerised telescope from a remote computer over a telephone line

(Martin and Hartly 1985). The early 90’s saw the emergence of the first effective

19

robotic telescope at the University of Bradford UK (Baruch 1992). This facility was

funded by the UK Particle Physics and Astronomy Research Council and the principal

aim was to establish the validity of the observing requirements of robotic telescopes as

laid down by the UK professional astronomical community. The system was

inaugurated in December 1993.

The time of this facility coincided with the commercial availability of the cooled CCD

camera, and the marriage of these two technologies, coupled with the availability of low

cost, powerful PC’s, fostered a growth both in numbers of robotic telescopes and their

level of sophistication. The UWS telescope benefited from these developments.

20

CHAPTER 2. - MECHANICAL RESONANT FREQUENCIES

2.1 RESONANT FREQUENCIES Before commencement of the design of the stepper motor drives and the associated

gearing, consideration was given to the possible interaction between electronic drive

pulses and the mechanical resonant frequency of the various components in the

telescope support structure. Indeed, each separate mechanical component would have a

fundamental resonant frequency, with the probability of several harmonics. Given that

there are two major mechanical assemblies to the telescope, each comprising several sub

sections, a large number of resonant frequencies were predicted, each having its

associated harmonics. It was thus necessary to establish what these resonant frequencies

were and ensure that none of the standard tracking drive pulse rates was selected at

those resonant frequencies.

2.2 METHOD USED

A simple method was used to determine the relative amplitudes and position in the

spectrum of these frequencies. A vibration sensor was attached to the section of the

telescope selected to be under test. A calibrated impulse was applied to that section via

a small hammer mounted to act as a pendulum. The energy imparted to each test point

could be assumed to be relatively constant by releasing the pendulum from a fixed

height. This was achieved by using a small electric magnet at the holding point at the

top of the swing and to avoid a secondary “bounce “impulse, a second electro magnet

was positioned towards the end of the pendulum swing and timed to activate during the

return swing of the pendulum, thus catching and holding the hammer. The output of the

vibration sensor was fed to a MacLab console which recorded the peaks of resonant

frequency and harmonics.

21

This procedure was repeated on the main sections and sub-sections of the telescope and

the combined results are shown in the figure below.

fig 13.Relative amplitudes of the telescopes resonance frequencies.

It can be seen from the above plot that the resonant frequencies ranged from about 100

Hz to 2.1 KHz. More importantly, the spacing of these resonant frequencies was

approximately even across the band, and these ‘gaps’ allowed considerable freedom in

selecting suitable drive pulse frequencies.

The initial drive train used a reduction gear box with a ratio of 11050:1 and the stepper

motor had a 1.8 deg. step angle. The polar axis rotation time was 23 h 56 m 04.1 s.

Roller rotation therefore was 147.25 m/turn, input into the gear box was 0.79956 s/turn,

thus the stepper frequency was calculated to be 250.1 Hz. It can be seen from the above

plot that this drive frequency fits neatly between the first and second resonant

frequencies.

0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 (Khz)

Relative Amplitude

Frequency

22

CHAPTER 3. - ALIGNING THE EQUATORIAL HEAD

3.1 CRITERION FOR LONG EXPOSURE

A substantial quantity of the research work to be carried out at the UWS Telescope will

depend on the results of long exposure astro-photography or photo-electric and CCD

photometry. The essential criterion for long exposure techniques is that the image

remains stationary in the field of view of the measuring device for the duration of the

exposure.

Two variables determine the accuracy with which this criterion is maintained:

(a.) the tracking rate of the R.A. drive, and:

(b) equatorial alignment.

For equatorial alignment to be ideal, the polar axis of the telescope must be coincident

with the celestial axis, and the declination axis must be perpendicular to the polar axis.

An approximate alignment was attained during the telescope’s manufacture and

installation. During fabrication care was taken to ensure that the polar axis was angled

as close to 33.75 degrees to the horizontal as was possible. The latitude of the UWS

Observatory site is 33 degrees 45.725 minutes South. The UWS telescope mounting is a

tripod configuration with one mounting foot at the Northern end and two adjustable

mounting feet at the southern end, one to the East and one to the West. Vertical

adjusting screws are fitted to each foot to allow fine adjustment of the height of each

mounting point individually. Furthermore, east-west movement of the Southern end of

the telescope is accommodated by horizontal adjusting screws in the east/west direction.

The permanent retaining bolts are fitted into slots which when tightened hold the

telescope in permanent position once the alignment is complete.

3.2 ALIGNMENT METHOD

The Astronomy Department of UWS had purchased some black and white CCTV

equipment primarily for use in demonstrations of the facility to the general public,

23

school groups, etc. It was decided to use part of the TV equipment in the alignment

process. The apparatus consisted of;

a) a 17” monochrome TV monitor

b) a monochrome 1/3 inch CCD TV camera

c) a Tektronix TV pattern generator type TSG 95.

To eliminate errors in the TV system due to scan non-linearity and scan rotation in the

TV monitor, a cross hatch pattern from the TSG 95 pattern generator was displayed on

the 17” monitor and a copy of this pattern was traced on to the front glass of the picture

tube using a thin felt tipped pen.

fig 14. Eliminating non linear scan error using an electronic pattern generator

As well as eliminating any scan errors in the monitor, the traced graticule provided an

accurate scale to measure drift because the electronically generated video lines were

24

separated by the exact number of TV scan lines. The vertical scan circuitry of the

monitor was modified to increase the vertical scan by approximately 50% to further

increase the scale and therefore the reading accuracy of the graticule. The CCD camera

was attached to the telescope eye piece and its output fed to the 17” monitor.

Note: It became clear during the subsequent alignment procedure that

significant parallax errors could be introduced into the measurements

because of the thickness of the front glass of the CRT i.e. the image

created on the phosphor of the tube was displaced approximately 10 mm

behind the cross hatch trace on the front of the glass. This could have

been eliminated if the pattern generator had been genlocked to the CCD

camera, and the two video sources mixed or keyed up stream of the

monitor. As a genlock facility was not available on the Tektronix

TSG 95 particular care had to be taken to avoid these parallax errors.

Using a spirit level and the east/west height adjusting screws, the southern end of the

telescope was made to be approximately horizontal as a basic starting point.

3.3 ALTITUDE ADJUSTMENT

To align the CCD camera’s rotational position a bright star at the zenith was positioned

in the vertical centre of the picture and the sidereal drive turned off. As the star tracked

across the field of view the camera was rotated until the trajectory of the star was

parallel to the horizontal graticule on the monitor. Monitoring the movement of the star

relative to the fixed graticule became the basis of measurement. The geometry of the

alignment of a telescope is as follows.

A star is selected in the east and another in the west. Both stars should be at least 5

hours from the meridian and at a declination of about 45 degrees south. Positioning

each star in turn on the centre of the monitor graticule and with the sidereal drive turned

on, a movement due to misalignment will be noted in a north/south direction. If the east

star drifts north and the west star drifts south the elevation of the south end of the

telescope is too small. Conversely, if the east star drifts south and the west star drifts

north the elevation of the south end of the telescope is too great.

25

The table below shows the adjustment increments made and the resultant alignment

error.

Meas. No Duration

Mins

Star Error Direction Adj Dir Adj Size

1 6 E 45 N S down 4.7 mm

2 6 W 22 S S down 1.2 mm

3 6 E 18 N S down 2.6 mm

4 6 W 5 N S up 0.6 mm

5 10 E 2 S S up 0.8 mm

6 10 W 2 S S down 0.2 mm

7 10 E 1 N S down 0.1 mm

8 10 W 0.5 N S up --

9 10 E 0.5 S S down --

10 15 E < 0.5 -- --

fig 15. Elevation adjustments and resulting error

Note – Error units are numbers of pairs of TV scan lines.

Adjustment magnitude units are based on degrees of rotation and thread pitch of

the adjusting bolt.

26

3.4 AZIMUTH ADJUSTMENT.

The technique used for azimuth adjustment was similar to that used for altitude

alignment. A star was chosen near the Meridian and close to the celestial equator. The

applying geometry states that if the star drifts north then the azimuth error is towards the

NW-SE direction. i.e. the southern end of the polar axis is pointing east of south. The

following table shows the increments of azimuth adjustment and the resulting error.

Meas No Duration

Error

Direction

Adj Dir

Adj size

1 5 37 North West 10 mm

2 5 22 North West 6.5 mm

3 5 12 North West 5.5 mm

4 5 4 South East 5 mm

5 10 2 North West 2 mm

6 10 1 South East 1 mm

7 10 1 North West 0.7 mm

8 10 1 South East 0.3 mm

9 20 1 South -- 0.1

10 20 < 0.5

fig. 15.1. Increments in azimuth and the resulting error.

27

At the completion of this alignment procedure, zero drift could be measured over

a 20 minute viewing session with the resolution of the equipment used. A non-

interlaced or a 100Hz frame rate TV system may have improved this resolution.

28

CHAPTER 4. - INITIAL TRACKING AND SLEWING CONTROL SYSTEM

4.1 TRACKING AND SLEWING SYSTEM

To allow students and the viewing public an opportunity to make use of the UWS

Telescope during the construction period of the computer controlled robotic system an

interim tracking and slewing drive system was installed. It proved to be an economical

and reliable solution and its tracking accuracy was sufficient for general applications,

however, not sufficiently accurate for long exposure measurements.

It consisted of a variable frequency oscillator driving a proprietary stepper motor

controller (RCC type SMD-1) which in turn drove a Vextra 1.8 degree per step motor

through a 11,050:1 gearbox on to the 9.6:1 Polar disc drive. The 1.8 degree per step

motor through the above gear reductions produced a step size in the sky of 0.06 arc

sec. Further, a stepping frequency of 250.1 Hz was calculated to produce the correct

tracking rate. A stepping frequency of around 6 KHz would give a workable slew rate.

The same variable frequency oscillator and stepper drive was used for the focus stepper

motor on the secondary mirror mount. A bank of relays switched the drive outputs from

the stepper driver to each motor. The following diagram shows the circuit of the

variable frequency oscillator.

29

fig 16. VFO Circuit Diagram

A potentiometer was mounted on the hand paddle to provide a variable voltage input to

the variable frequency oscillator (VFO) which enabled varying stepper rates for both

HA and DEC. The potentiometer was of the type fitted with a push-pull switch action

on the shaft and this switch was used to change the VFO input from the hand paddle

potentiometer to an internally mounted multi turn trim potentiometer which was

adjusted to provide optimum tracking pulse rate. A small hole in the side of the hand

paddle gave access for screw driver adjustment of this potentiometer as would possibly

be required from time to time.

Switches were mounted on the top edge of the hand paddle to switch the output of the

stepper motor controller to any one of the three stepper motors in the system. Pointing

to a star that therefore required sequential and repetitive actions in both HA and DEC.

30

Once the target was centred, the focus motor could be individually activated. However,

because the tracking motor could not operate simultaneously with the focus drive motor,

any focus adjustments needed to be done quickly as the star moved across the field of

view. Considerable operator practice was needed before the technique could be

mastered. The operating sequence was:

a. Move HA axis to the approximate pointing position

b. Move DEC axis to the approximate pointing position

c. Fine tune HA axis for object centre

d. Fine tune DEC axis for object centre

e. Check/adjust focus

f. Repeat c and d

g. Push control knob to invoke VFO tracking rate

h. View

The figure below shows the original hand paddle.

fig 16.1 Original system hand paddle

31

CHAPTER 5. - THE VIDEO SYSTEM AT THE UWS

OBSERVATORY

5.1 TASKS

The video system at UWS was required to perform several tasks covering research, on

site education, public viewing, and remote viewing through the Hands on Universe

program.

5.2 ON SITE EDUCATION.

The UWS Nepean Observatory has a small lecture theatre attached to the main

telescope building. Several courses are offered by the astronomy group ranging

from Undergraduate Degree courses to advanced Masters and Doctorate degrees.

In conjunction with the formal courses offered by the University, school groups

are invited to attend lectures and demonstrations as an aid to their high school

science courses as well as fostering a greater interest in science, and astronomy

in particular. It was clear that most, if not all, of the imaging devices needed to

be displayed on all the large screen colour TV receivers as well as the large

screen TV projector mounted in the Observatory’s lecture theatre. A system of

U.H.F. distribution was selected over base band video to reduce cabling and

installation costs and to free the lecturer to select any required channel from any

position in the lecture hall via a standard infra red remote control. Base band

video distribution would have increased the cost of the installation due to the

need for a quantity of video distribution amplifiers and extra cabling, but would

also have made it necessary for the lecturer to be at a fixed point in the lecture

theatre i.e. at a switching panel, to select the required video source to be

displayed. An added advantage of R.F. distribution was that the multi-channel

signal could be sent to other buildings on campus either by coax cable or via

microwave link.

The initial video system included 10 video sources, and as it was highly

probable that other sources would be added in the future, the system design

32

needed to allow for easy integration of additional video facilities. A multi input

electronic routing switcher would have provided an ideal heart for an expandable

system, but as budgetary constraints prohibited this approach, a passive video

patch panel was constructed.(See later comments on the desired router, page 42).

fig 17. Video patch panel.

33

Initial sources were as follows:

a) 1/3 inch monochrome high resolution CCD camera mounted on the

instrument

turret.

b) 1/3 inch monochrome CCD camera mounted on the C8 telescope.

c) 1/3 inch colour CCD camera designated “Moon cam”.

d) 1/3 inch monochrome CCD camera floating.

e) ST 6 video capture.

f) ST 8 video capture.

g) 1/3 inch monochrome CCD camera showing a wide angle view of the inside

of the dome.

h) Cuseeme colour camera mounted at the operators’ desk for internet display.

i) 1/3 inch colour CCD camera mounted outside the dome designated “Cloud

cam”.

j) VHS video recorder.

The principal camera for the telescope is a Santa Barbara Instruments Group (SBIG)

ST8 integrating CCD camera. This camera is based on a Kodak 1600 chip which has

1.5k pixels x 1k pixels, each pixel being 9 microns in size. In addition to the principal

chip inside the camera there are smaller chips which are designed to pick up the off axis

star images, and to centre these images at very fast frame rates and to feed back to the

telescope drive to ensure the telescope is in fact tracking the stars as they go. This

eliminates many of the problems referred to above in terms of refraction and polar

alignment. Experience with this camera has shown that the images of stars as faint as

19th or 20th magnitude can be obtained in exposures of 5 to 10 minutes which makes the

camera and this telescope combination a very competitive tool in terms of many areas of

science, principally astrometry and photometry. The images captured by this camera are

analysed on a dedicated computer which is called the “camera computer” using the

software which is supplied with the camera (called CCDOPS), or alternatively the

maxim DL software which was purchased after the installation of the camera. The

image from this camera and from this computer monitor can then be distributed either to

34

the internet or alternatively other parts of the building, in particular to the TV monitor

and data projector in the lecture theatre. The other cameras on the telescope are

designed to piggyback on the main camera and on the main instrument. In particular

there is an 8” Celestron telescope mounted parallel to the main instrument with a black

and white video frame rate surveillance type camera inserted into the eye piece. This

instrument is particularly sensitive to Luna features and gives a very satisfactory view of

the moon in less detail than the main camera but gives a frame rate so atmospheric

change and tracking changes of the telescope etc can be seen. In addition there is a

colour wide angle lens arrangement on the side of the telescope designed to give a full

view of the moon. The field of view is approximately 45 arc minutes in the vertical and

this gives a full view of the moon and is ideally suited for the entertainment and

education of younger people who identify very clearly with the moon as part of their

studies. This camera when fitted with a solar filter also gives a full frame view of the

sun and has been used for web broadcasts of partial solar eclipses seen over Penrith.

We refer to this camera as the “moon camera” and it consists of a 1/3 inch CCD

surveillance style colour camera fitted with a 300mm telephoto lens. This combination

gives an ideal field of view of about 1 degree x 45 arc minutes.

It was the intention to fit 2 other cameras to the main telescope, one of these was to be

an ST6 integrating, cooled CCD camera (of less power than the principal ST8) which

was to carry a wide angle camera lens for viewing of wide angles of the sky. This

camera was to be mounted at the top of the telescope.

In addition there was also to be a frame rate video camera of high sensitivity mounted

at the top as a “constellation camera”. As well as cameras on the telescope there is a

small CCD surveillance camera mounted inside the dome which shows images of the

telescope and people in the dome.

35

fig 18. Moon cam mounted on the side of the main frame

36

Irrespective of the number of video pictures being generated within the

university, consultation with the lecturers indicated that no more than five

different sources would be required during any one lecture period. With this in

mind, a five channel U.H.F. TV modulator system was installed utilising

channels 43, 45, 47, 49 and 51. The channels chosen were somewhat at random

whilst having regard for potential interference from high power U.H.F.

transmitters already operating in the Sydney basin, mostly commercial and

community access TV channels.

While restricting the total of U.H.F. channels to five, provision was made

to quickly change any of the U.H.F. modulator inputs via the video patch panel

so that any of the modulators could be connected to any of the video sources at

any time. See the video schematic diagram for further detail.

fig 19. Rear view of the UHF modulators

37

5.3 REMOTE VIEWING

Two avenues for remote viewing were considered.

i) The Web Page:

Within a week of completing the video switching and distribution

system, UWS had an opportunity to display the images of a solar eclipse

on the UWS home page on Tuesday 16th February, 1999. In preparation

for the eclipse a 1/3 inch colour CCD camera was mounted on the side of

the main telescope and was fitted with a 500 mm lens with an ND solar

filter.

The camera utilised a 1/3” colour CCD with 512 horizontal x 582 vertical

pixels (9.6 micro m horizontal pitch). During the eclipse the images were

recorded on a VHS tape recorder and were displayed on colour monitors

throughout the Observatory. To facilitate remote viewers the image was

displayed on the university web page using the following technology. A

video capture device (Video Blaster I.E. 500) was used in conjunction

with the software package “Image Pals Image Editor” and saved in jpeg

format. This was uploaded to Web server-bacall.nepean.uws.edu.au

using wsftp.exe. This process was to be fully automated but due to

software conflict between SNAP+send and Video Blaster drivers, the

capture and upload sequence was performed manually every 45 seconds.

This software conflict has since been rectified and real time images are

now available to the net. Feedback on the educational value and the

extraordinary interest shown in this home page imaging is discussed later

in this document.

ii). The results of a questionnaire distributed to lecturers and potential remote

users, was evident that whichever video source was currently being

displayed on the web page, should be that which is being displayed on

the Cuseeme overlay on the main telescope display screen.

38

The video sources available to the remote viewer were more numerous

than those likely to be used in any one lecture session or indeed in a

lecture room environment. For example, apart from the normal

instrument mounted cameras, images needed by remote viewer could

include:

• CLOUD-CAM. The outdoor colour CCD camera mounted on a

remotely controlled pan and tilt unit to allow remote users to

check during late afternoon the likelihood of evening cloud.

• The Cuseeme CCD colour camera to enable real time, face to face

conferencing.

• The view of the main telescope from inside the dome to show

telescope type, mechanical features, movement etc.

5.4 REMOTE SCIENCE

This area of remote viewing was required to fulfil the needs of a range of users

with vastly different levels of astronomical knowledge and scientific

requirements. In spite of this, it seemed probable that any of the available video

sources could be called upon at some time by any of the potential users. In most

cases the required image would be needed to be displayed as an overlay on the

control panel screen, and in applications requiring better definition, stored and

dispatched via email at a later time. The latter approach would be more

appropriate for instance following a long duration data gathering exercise using

the ST8.

These images, plus other sources commonly used in house needed to be remotely

selected by the remote viewer/operator as well as being selected locally. To

achieve this dual role, an inexpensive remotely controlled 10 input vision

switcher was purchased (M.C. Corporation model YH438C). This vision

switcher not only enabled switching of individual inputs to a selected output but

also provided 2 quad images as outputs. The first quad selection combined

cameras 1 through 4 in a quad format, and the second gave cameras 5 through 8

39

in quad. In total any one of 10 outputs could be selected being cameras 1

through 8, quad A, quad B. The remote control of the YH438C is via a high

density 15 pin D connector requiring 6 logic control lines (see the video

schematic diagram for details page X), and was driven by the ACE control

system.

fig 20. YH438C Quad video switcher ( smart dome control unit below)

5.5 RESEARCH.

The principal video research tools available to UWS were a large format ST8 CCD

integrating camera (by Santa Barbara Instrument Group) and two ST6 integrating

cameras. The images from these cameras were required to be available at several

destinations being:

i) the UWS Observatory image library

ii) remote users via the Internet

40

iii) public viewing monitors within the Observatory

iv) on site lecture theatre monitors and large screen projectors.

Video capture cards were used in the camera PC so that both digital and

composite video signals were available for distribution.

5.6 PUBLIC VIEWING

Due to the limited size of UWS observatory facility, public viewing times needed to be

scheduled outside of formal lecture periods. This physical restriction freed the lecture

theatre UHF distribution system for public viewing use. However, further public

viewing facilities needed to be added to the upper level of the observatory adjacent to

the main telescope. Two TV monitors were placed adjacent to the telescope, and input

selection of any of the sources was made available to these monitors by passive rotary

switch banks. Two monitors were chosen to enable the image from the main telescope

to be displayed along side a wider view from the three inch or C8 telescopes.

The video system as described above is probably as flexible a system as could be

managed under the given budget constraints. Unfortunately it became clear that because

of the system complexity, appropriate training had to be given to those faculty members

who were likely to have specific and different demands on the system. A common

question being “How do I configure the system to get it to do what I want ?” Instruction

was given to each operator on how to change the system from its standard/default

configuration to the required configuration for his/her session. After some weeks of

multiple usage it became clear that more work was necessary to simplify the operational

controls and to simplify the method of setting the system to a varied number of standard

configurations. The main problems were introduced through operators not returning the

configuration to the default condition after use. This meant that the next operator would

input his requirements assuming he was starting from a default setting, and finding that

the end result was not as expected and certainly not as required. Two solutions were

considered.

41

a. A colour coded default finder.

The original method of setting the system to its default configuration was

to refer to the system block diagram mounted on the equipment rack in

the computer room. Reading this block diagram and initiating the

required changes proved to be a more difficult task for most operators

than had been expected. To overcome the need to refer to the block

diagram, a colour code system was introduced whereby mating

connectors on the patch panel, switch positions etc. were colour coded to

a standard format e.g. connecting the red patch cable to the red patch

connector and/or switching to blue along the chain quickly attained

default conditions. From here, each operator could then modify the setup

to provide his/her standard configuration for the next session.

Reference to the block diagram would still need to be made where a

non standard configuration was required or if any changes needed to

be made to an existing standard. These changes proved to be a regular

occurrence, but the colour code system again was a great help in

returning the system to default.

b. The need for a microprocessor controlled video routing system.

Most of the problems, queries and out time that occurred in operating the video

system were through operator error. This was due to either unfamiliarisation

with the system or requesting the system to perform a task that it was not

designed to do. Removing the human element from the back ground operations

of system setup seemed appropriate and a microprocessor controlled video

routing switcher seemed the best solution. Several commercially available

systems were investigated, all being of matrix configuration made up of 16

inputs and into 16 outputs .Parameters such as frequency response, video path

cross talk, distortion, control panel configurations, power consumption and ease

of maintenance were compared. A most important operational feature in the

considerations was the ability of the system to perform what are known as “salvo

takes”. This feature permits a number of standard matrix configurations to be

42

stored in memory and activated at will by one or two key strokes. This feature

seemed mandatory for UWS facility in that each operator could be allocated a

dedicated matrix configuration number which would be entered at the start of

that operator’s sessions. If a public viewing session is taken as an example the

optimum system configuration could be manually entered into the processor and

allocated salvo take “one”. The salvo take facility then allowed all public view

sessions in the future to be configured by one or two key strokes from the

supervisor. Once this was established any modifications to the standard matrix

configuration could be carried out by direct switch action into the matrix. After

considering the requirements a short list of two quite different systems resulted.

These were;

i) A matrix fully self contained in a 19” rack mount cabinet with both local

and remote controls, and redundant power supplies manufactured in Australia by

Talia Video. The Talia systems are aimed at the broadcast and semi professional

video production market. As such, the video performance specifications met or

exceeded the requirements of the UWS facility. Moreover, provision could be

made for easy system expansion if required some time in the future.

ii) A matrix system manufactured in the USA by Javalin Inc. The Javalin

system is supplied in kit form for assembly into a desktop personal computer.

Neither local nor remote switch operated control panels are available as all

matrix configurations are done via the PC screen. Performance specifications of

the Javalin system were not as rigid as the Talia device but were considered

adequate for the UWS facility. The major limitation with the Javalin system was

the inability to provide individual local or remote switch panels. At the time of

writing, budgeting considerations prohibited the purchase of either of the above

video routing systems and as a result, the colour coded manual system is

currently in use. See chapter headed “Future work to be carried out” in chapter 9

for further details.

The next page shows the video schematic diagram of the UWS TV system.

43

fig 21. Video schematic diagram

44

5.7 A NOTE ON GAMMA CORRECTION

If the early days of television development had started with the technology of liquid

crystal or plasma displays, the concept of gamma correction would never have been an

engineering issue. Alas, cathode ray tubes (CRT) were the first display devices and as

such the TV industry is burdened with a forced, built in distortion of the television

image which needs to be corrected later in the processing chain.

The cathode ray tube was invented by Karl Ferdinand Braun in 1897. It is constructed

of an evacuated glass envelope with a Phosphor-coated screen at one end which emits

light when hit by electrons generated by a heated cathode. These electrons are focused

into a beam and forced to scan the phosphor screen by a process of magnetic deflection.

The intensity of the electrons hitting the screen, and therefore the intensity of the light

output is varied by modulating it with a control grid in the electron gun.

It was soon discovered that the intensity of the light output of the CRT screen was not

proportional to the intensity of the electrons being emitted by the electron gun. More

specifically, the light intensity in the dark (grey) areas of the picture was less than the

proportional amount of electrons would be expected to create. i.e. the dark areas were

being crushed into the black.

This distortion clearly needed to be corrected and extra gain was needed to be added to

the grey, and more so in the dark grey, areas of the picture. Extra gain equates to extra

noise in the video signal and unfortunately the human eye is more sensitive to noise in

the dark areas of a picture than in the brighter areas. The electronic circuits to produce

this extra, non-linear gain therefore needed to be designed with optimum performance

and greater complexity.

It seemed obvious at this stage that the number of television cameras in use at any one

time would be vastly outnumbered by the number of television monitors and receivers,

so a decision was made on economic grounds (by the engineering fraternity) to include

this extra non-linear gain in all cameras, rather than in each CRT display device. A

45

“pre-correction” if you will. The commonly accepted value of gamma in today’s TV

cameras is 0.5 i.e. the voltage output of the video signal is raised to the power of 0.5.

The diagram below shows the relative curves and the resultant linear output.

fig 22. Gamma Correction curves.

LCD and plasma displays show a linear transfer characteristic (i.e. voltage input is

directly proportional to light output). However, because all cameras still need to

accommodate CRT displays, and thus the signal is gamma pre-corrected, a “de-gamma”

circuit must be incorporated in the LCD type displays. It is assumed that CRT devices

will eventually be phased out but it is difficult to imagine how and when a removal of

gamma correction could take place because the overlaps in technology will demand that

correction or de-correction is necessary to cater for all existing devices.

The relevance of gamma in TV astronomy is that most of the viewing of celestial

objects displays scenes of a black background, with white objects in the foreground. i.e.

very few or no grey areas. Moreover, if grey areas are present they are often unwanted

aberrations. The exception to this rule would be in viewing craters of the moon where

grey areas exist and in most cases are required to be replicated in the viewed image.

46

Consequently using conventional gamma corrected cameras in TV astronomy introduces

an unnecessary “black stretch” in the video path and the noise in black that it, by

definition, enhances. An added desirable feature therefore, when selecting a television

camera for astronomy use is an external gamma control, at its simplest “gamma

ON/OFF”. Using such a feature can minimise thermal noise in the black areas of the

picture thus enhancing the effect of the overall image. Due to budgetary constraints, the

only camera fitted with adjustable gamma was the one mounted on the instrument turret.

fig 22.1 1/3” CCD camera with adjustable gamma

47

5.8 STAR-TRAK

In the earlier chapter covering mechanical alignment of the telescope, a description is

given of the closed circuit television operation to aid in the measurement of system drift.

During this alignment procedure it became clear that errors due to parallax could

readily be introduced, or at the very best, that extra time and care had to be spent in

making sure that parallax errors were minimised. With this in mind a software

application called Star-Trak was developed. As the design goals of Star-Trak were

prepared, its application to other areas of astronomy became clear and a far more useful

research tool resulted.

To avoid parallax errors when using a cathode ray tube for measurements, the image

being viewed by the CCD camera must be mixed electronically with the reference

graticule prior to display. The technically correct method to perform such a mix is to

KEY the foreground video (i.e. the graticule) into the background video (i.e. the star

scene being viewed). To perform a key function, a “hole” is cut into the background

video in the size and shape of the required foreground. This hole is then filled with

another video source, in our case 100% peak white. This key method allows for a

variable grey scale to be used as the fill signal which, while not defined at the time of

development, was seen to be a possible use in the future. The alternative to key

technology was an additive mix approach which although electronically easier to

implement has the disadvantage that the live video sources are added over the entire

frame resulting in loss of grey scale integrity.

To achieve a stable keyed picture, the scan rates of the two video sources need to be

synchronised and locked horizontally and vertically, or “genlocked”. Several

proprietary PCB’s were commercially available which provided most of the required

genlock and key functions. The one chosen by UWS was the system manufactured by

Cueword Pty Ltd in Sydney. The Cueword system was developed for use by TV

stations for teleprompting scripts and open captions for on-air presentation. The benefit

of the Cueword system was that it provided an onboard genlock and key function which

were intended to output onscreen captions for the hearing impaired. So, the celestial

image could replace the “talent” image and the graticule would replace the captions. All

that was needed now was a software package which would generate a suitable graticule.

48

Clearly a rigid, non moveable graticule was required as a reference for measuring image

drift, and a suitable solution was a cross hair in the centre of the television raster. With

a view to future experimental work, a second mouse-moveable cross hair was provided

which could be moved to any part of the TV raster. The reason for the development of

the moveable cross hair was that it could be used for the following task.

a. An auto “go to” function.

Operationally the auto go to function required the moveable cross hair to be

moved to the stellar object under study. A click on the mouse would then instruct the

software to determine how many pixels both horizontally and vertically the moveable

cross hair was displaced from the fixed cross hair at the centre of the raster. A new

reference could then be calculated either by Star Trak, and the telescope would move to

that new position automatically.

b. Measuring angular distance between stars.

By placing the fixed cross hair on one star, and placing the moveable cross hair

on another star, the known angular separation between the two stars could be

used to perform an auto calibrate function. From then on, a digital readout on

the CRT would give the angular separation between the centre cross hair and any

other position within the raster that the moveable cross hair was placed.

c. As a teaching aid.

The moveable cross hair could be used as an electronic pointer during lectures,

tutorials and public viewing.

5.9 PRECAUTIONARY NOTE.

Many CCD cameras of the type used in astronomy are chosen for reasons of high

sensitivity, low noise, adjustable gamma and stability of gain and scan frequency.

Under normal circumstances the tolerance of scan frequency stability is of little

consequence because the average TV display monitor is designed to accept a broad

range of scan frequencies to accommodate multiple standards, noisy sources and poor

synchronizing pulse trains from video cassette recorders. Horizontal scan frequency and

49

stability are of increased importance when dealing with genlockable equipment. Not

only should the nominal horizontal centre frequency be within 2 Hz of the specified

standard, but drift, mainly due to temperature changes, should be less than a further 1

Hz. This is because the sync pulse detector and separation circuitry of the average

genlock system is far less forgiving than a standard TV monitor.

50

CHAPTER 6. - ENGINEERING APPROACHES TO

TELESCOPE AUTOMATION

6.1 GO-TO

The basic requirement of a telescope automation system is to have the device ‘Go-To’ a

specified target and accurately track that target as it moves across the sky.

Several levels of engineering can be employed in achieving the above goal. Cost

is the most common factor in determining the level of sophistication of the control

mechanism. The more sophisticated and thus more expensive levels giving greater

accuracy compared to the less expensive, more basic models. Furthermore there are two

fundamentally different engineering concepts on which to build a Go-To control system.

Firstly, an open loop system of electronic control where a drive system responds

to instructions given by an operator from a keyboard or hand paddle. In an open loop

system, no positive feedback is given to the drive system control to give confirmation

that the required action has taken place with accuracy, or indeed if the action has taken

place at all. Furthermore, if the telescope is moved manually (e.g. n degrees in DEC)

the drive system has no means of recording this change and so believes that the

telescope is still pointing to its pre manually moved position. The end result of this is

that when a new Go-To instruction is given, the system uses an invalid starting point and

drives the telescope to a new position which will be ‘n’ degrees in DEC off the required

target.

To overcome this problem, many telescopes using open loop systems eliminate

the possibility of performing a manual move so that the electronic drive system becomes

the only means of movement and therefore can maintain constant position surveillance

51

integrity. This of course leads to rendering the instrument useless if a failure of power

supply or a fault in the drive system occurs. The first drive system at UWS, described

earlier, was an open loop system, however manual override was maintained.

Secondly, the much preferred closed loop system may be used where

components (usually optical encoders or precision potentiometers) are mounted on the

telescope drive train to provide a constant feedback to the control electronics of any

movements whether manual or automated. Consequently if the telescope is moved the

control system will know where the device has been moved to and thus does not lose its

orientation.

The precision with which these devices can deliver the feedback information to

the control electronics is paramount in determining the accuracy with which the

telescope will ultimately point and track. The key parameters in attaining this precision

are:

The resolution of the encoder

Minimising backlash in coupling devices

Slippage between friction drive rollers

Ability to accommodate slight off-axis mounting.

Optical encoders, or shaft encoders, monitor the direction of rotation and the

distance travelled. Two encoders are usually employed on an astronomical telescope,

one for feedback of movement in the Declination and the other in Right Ascension. The

direction information is usually supplied via one pair of conductors and the step counts,

or ‘TICS’ via another pair. Careful consideration needs to be given to proper earthing

and shielding techniques during installation because stray TICS entering the feedback

loop via external noise or power supply spikes will corrupt the final count at the

processor end of the chain. An alternative to the optical encoder feedback system is a

d.c. servo controlled system. The feedback device in this application is usually a

precision multi-turn linear curve potentiometer. The position of the moving arm of the

52

potentiometer, and thus the resistance or voltage output is a direct reflection of the

position of the telescope.

The gearing used to couple the multi-turn potentiometer to the telescope must be

carefully chosen so that the maximum angular movement of the axis concerned does not

exceed the end-stop to end-stop length of the potentiometer’s conductive track. This

usually calls for a high gear ratio, using a chain of gears, which is in turn conducive to

the introduction of increased backlash. The limiting linearity of the track of even the

best potentiometers, plus the mechanical problems introduced via a complex gear train

usually relegate the d.c. servo system to a less expensive telescope drive system. The

slight extra cost of a servo motor verses a stepper motor is more than offset by the lesser

cost of the feedback sensor. A summary of the benefits and drawbacks of stepper and

servo motors is given below.

6.2 STEPPER MOTOR BENEFITS

• Rugged and reliable. Steppers are mechanically very simple and apart from the

bearings no wearing components exist.

• Lowest cost solution.

• No maintenance. There are no brushes or other wearing parts requiring regular

checking or replacement.

• Industry-standard ranges (Nema or metric). Steppers are produced to standard

flange and shaft sizes so finding alternate sources is not a problem.

• Inherently failsafe. There are no conceivable faults within the drive to cause the

motor to run away. Since current must be continually switched for continuous

rotation most faults cause the motor to stop rotating. A brush motor is

internally-commutated and can run away if continuous current is applied. A

brushless servo relies on the feedback signal. If the feedback signal is damaged

or absent the motor can run away.

• Not easily demagnetised by excessive current. Owing to the perpendicular

planes of the permanent magnet and alternating flux paths, stepper motors will

53

more often melt the windings before demagnetising the permanent magnet as

would happen in a brushed motor.

• Inherently stable at standstill. With DC flowing in the winding, the rotor will

remain stationary. There is no tendency to jitter around an encoder position.

This is useful in applications using vision systems.

• Can be stalled indefinitely without damage. There is no increase in motor

current as a result of a stall as in a servo system. There is no risk of overdriving

a stepper system due to large loads.

• High continuous torque in relation to size. Compared with brushed servos of the

same size, a stepper can produce greater continuous torque at low speeds.

6.3 STEPPER MOTOR DRAWBACKS

• Ringing resonance and poor low speed smoothness. These are criticisms

generally levelled at full-step drives. These problems may be almost wholly

overcome by the use of a high resolution drive.

• Uses full current at standstill. Since current is needed to produce holding torque,

this increases motor heating at standstill.

• Noisy at high speeds. The 50 pole rotor has a magnetic frequency of 2.5 kHz at

3000 rpm. Magneto-striction causes a correspondingly high pitched sound.

• Excessive iron losses at high speed. Again due to the high pole current,

hysteresis and eddy current losses are higher than in a servo. A stepper is

therefore not recommended for continuous operation at speeds above 2000 rpm.

6.4 BRUSH SERVO BENEFITS

• Low cost. Brush servo motors are well developed and are inexpensive to

produce.

• Smooth rotation at low speeds. Brush motors are available which are specially

designed for low speed smoothness with a large number of commutator

54

segments. Brushed motors are the smoothest of the three discussed motor

technologies.

• Low cost electric drive. A dc brush drive can be made very economically since

only a single bridge circuit is required.

• No power used at standstill. With no static loads on the motor no current is

required to hold position.

• High peak torque availability. In intermittent duty applications, particularly

when positioning mainly inertial loads, the motor can be overdriven beyond its

stated continuous rating.

• Flat speed/torque curve. This provides optimum performance with easily

generated linear acceleration ramps.

• High speed attainability. Brush servos are typically good for speeds up to 5000

rpm.

6.5 BRUSH SERVO DRAWBACKS

• Brush maintenance. This is not necessarily a problem if the motor is easily

accessible, but a nuisance if the motor is not. Brushes also create dust as they

wear, thus limiting their use in environments where brush dust is not acceptable.

• Commutator limitations. Arduous duty cycles promote wear, and the mechanical

commutation limits top speed. Very short repetitive moves less than 1

revolution of the motor may wear part of the commutator.

• Poor thermal performance. All the heat is generator in the rotor, from which the

thermal path to the outer casing is very inefficient.

• Can be demagnetised. Excessive current can result in demagnetisation of the

motor.

6.6 BRUSHLESS SERVO BENEFITS

• Virtually maintenance free. The lack of a commutator and brush system

eliminates the need for periodic maintenance.

55

• Good thermal performance. All the heat is generated in the stator where it can

be efficiently coupled to the outside casing.

• Very high speeds possible. There is no mechanical commutator to impose a

speed limit, small motors are typically rated at up to 12000 rpm.

6.7 BRUSHLESS SERVO DRAWBACKS.

• Higher motor cost. This is largely due to the use of rare earth magnets.

• Electric drive more complex and costly. Six state or trapezoidal drives, are not

much more expensive than d.c. brush drives, but the higher performance sign

wave drive can cost several times that of the d.c. brush drive.

The following chapter (chapter 7) describes the motors and drivers chosen for the UWS

system.

56

CHAPTER 7. - THE CONTROL SYSTEM AT UWS

7.1 CHOSEN SYSTEM

The system chosen for automated control of the UWS Observatory Telescope

was that offered by Astronomical Consultants and Equipment, Inc (A.C.E.) of Tucson,

Arizona, USA. It comprises all the necessary hardware and software to automate an

equatorial mount telescope. It consists of a PC running Windows NT4 and a proprietary

ACE telescope control crate. The system controls the movement of the telescope, the

observatory dome rotation and the shutter. It uses an Oregon Micro System PC58-4E

digital IO card which is responsible for running the motors, reading the encoders and

other external inputs such an end stops, hand paddle, shutter condition etc. It is capable

of controlling up to 4 motor/encoder pairs.

The system drives DM/DR series Dynaserve servo motors and reads Dual

Quadrature Rotary encoders for the Declination and Hour Angle axes, and stepper

motors for the secondary mirror focus adjustment and also for the instrument selector

turret. These servo motors are of the brushless variety described in chapter 6 and are

able to provide resolutions up to 1,024,000 steps per revolution. They are direct drive

devices, using an outer-rotor design, allowing them to be coupled directly to the load

without the need for large reduction gearboxes which invariably introduce unwanted

backlash.

fig 26 . Outer-rotor construction of the Dynaserv motors

(Reproduced from the Dynaserv installation manuall)

57

A second advantage of the outer-rotor construction is the extra torque available. Torque

is proportional to the square of the sum of the magnetic flux of the permanent magnets,

and the magnetic flux of the stator windings. The outer-rotor design allows the

tangential forces of the rotor and the stator to work at a greater distance, thus increasing

the output torque. The diagram below shows output torque versus speed.

fig 27. Output torque versus speed of the DM/DR series motors.

(Reproduced from the Dynaserv installation manual)

In addition to overseeing the movement of the telescope and dome, the PC

monitors inputs from the weather station mounted on the Observatory’s roof and sends

drive instructions to the quad video switcher, assigning the required video source to the

input of the internet connection.

The interconnections of the ACE system at the UWS Observatory, plus the

relevant colour codings are given in the attached extracts from the ACE system

handbook given in appendix A.

58

7.2 MAKING THINGS EASY

When mounting the feedback encoders and couplers to the Hour Angle and

Declination axes of the telescope, standard proprietary hardware was used wherever

possible. However, because of the structure of the base of the rotating dome, a UWS

specific device needed to be constructed to mount the encoder which supplied feedback

of the dome position to the controlling PC. This was elegantly achieved by using parts

from a discarded semi-professional video tape recorder, in this case a Panasonic U-

matic. The capstan drive idler wheel, complete with its accompanying frame, bearings

etc, proved to be ideal. The idler wheel is a 10 cm diameter cast alloy wheel with a hard

rubber tyre fused around the circumference. This hard rubber tyre was designed for use

over many hundreds of hours of tape replay so, although thin in profile, the tyre proved

to be an excellent, high friction, minimum slip coupler between the metal dome base and

the encoder. The eccentricities of the dome’s base were compensated for by mounting

the base plate to a vertical pin hinge, and using spring tension to hold the idler wheel

against the dome base. If any slippage was to occur, a micro switch and cam system

was used as a method of recalibrating the encoder position each time the dome passed

its home site. Because of the heavy duty nature of the tyre and the roller bearings on the

idler shaft (part of the original U-matic recorder) this device has been operating

successfully for over 3 years.

59

fig.28 U-Matic idler wheel coupled to encoder below

7.3 SAFETY

Occupational Health and Safety issues mandated that many personal safety aspects to be

considered during the design and construction of the UWS Telescope and Observatory.

Safety aspects associated with building codes are outside the scope of this document,

however some aspects of personal safety considerations around the telescope are

mentioned here.

Because the UWS facility was to be open to school age groups, ranging in age

from 10 to 18, consideration needed to be given to ‘small hands in tight places’ in a

darkened, often blacked out environment in which a multi tonne device was slewing and

tilting at sometimes very high rates. To this end, mechanical aspects such as all sharp

edges and any small spaces between adjacent parts of the moving assembly needed to be

addressed first. In most instances the sharp edge issue was addressed merely by

60

rounding off all exposed edges of the assembly and the small space issue by fitting

cover plates to all openings that were a threat to personal safety.

A further consideration was the electric cabling associated with both the drive

motors/encoders, and the TV cameras and other turret mounted instruments. Because

the cabling requirements needed to be changed when using different measuring

instruments, some cabling needed to be free of the restrictions of hard clamped conduit

covering. Conduit, or spiral spring wrap, was used where possible but to cater for ‘one

off use’ cables, a series of strategically placed cable clips were mounted on the telescope

frame enabling the non standard cables to be locked safely into position.

In the event that any of the above precautions failed, a large ‘master stop’ switch

was mounted in a prominent position on the front plate of the telescope base. It was an

industrial grade, large, red, mechanically latching press to stop switch, wired into the

end stop circuitry of the telescope drive, so that if ever the switch was activated the

drive system would immediately shut down and remain so until the master stop switch

was reset to normal operating condition. As an additional safety aid, the dome camera

(mentioned earlier under ‘the video system’ p 33 item g) was fitted with four high

intensity infra red LEDS so that the operator in the control room below could see a clear

picture of attendees inside the dome on his 12” video monitor even during periods when

the area was blacked out.

61

fig 26. Control desk with CCTV monitor

62

CHAPTER 8. - A POINTING MODEL

8.1 OPTIONS

Two common methods exist for generating a pointing model. Firstly, the mechanical

and optical parameters of the telescope are modelled and the correction factors

calculated and introduced into the system. Secondly, a grid map can be used as a

foundation of the model where a library of corrections is accumulated in real time for

random pointing positions in the sky. This library of corrections can be added to (with

every observation if required) culminating in a very extensive set of correction data

enabling high pointing accuracy and repeatability anywhere in the sky. A spacing of

around 5 degrees between grid points around the sky yields optimal results.

The ACE system uses the grid map concept in its pointing model. In addition to the

above mentioned advantages, the grid map system is independent of the telescope’s

style of mechanics and optics, and is thus suitable for any telescope in which the ACE

system is deployed. Corrections are stored for each grid point and the model

compensates for mechanical flexure, bearing errors, polar misalignment errors and

refraction as a function of temperature and atmospheric pressure. Provided sufficient

correction points exist for neighbouring stars, up to 5 neighbouring grid points are used

in the model.

63

8.2 OBSERVATION DATA

The following is a sample set of observation data using the ACE grid map model. To

clarify the layout of the following listing, an explanation of the first line is given below.

20050404 is the UT date

032101 is the UT time to a second

2.9305704 is the HA in hours (+ = W, - = E)

-2.43…is the Declination

127.777 is the correction in ARCSECONDS for HA

-205.255…is the correction in ARCSECONDS in DEC

237.53 is azimuth in degrees

34.72…is altitude in degrees

-62.7 is the correction in ARCSECONDS for AZ

-236 is the correction in ARCSECONDS for ALT

10.0 is the temperature in degrees Celsius

1000 is the pressure in mb

FB was the observer

1788 is the bright star catalogue number and 28Eta Ori is the common name

20050404-032101 2.9305704 -2.4326253 127.7771427 -205.2557429

237.5384808 34.7206851 -62.7135958 -236.1635733 E 10.0 1000.0 FB 1788

28Eta Ori

20050404-032720 3.0251155 6.3035181 125.5909418 -230.4756303

246.7690042 39.6590271 -123.7449545 -244.1994319 E 10.0 1000.0 FB 1790

24Gam Ori

20050404-032929 2.5597752 7.3797017 87.3960669 -142.9729409

241.6100928 45.5598374 -65.2321762 -160.8361352 E 10.0 1000.0 FB 2061

58Alp Ori

64

20050404-033952 1.8981179 12.8199297 95.3869227 -283.7775123

237.0835690 56.3762604 -246.4487400 -265.6883847 E 10.0 1000.0 FB 2484

31Xi Gem

20050404-034603 1.9580830 2.3799053 47.2073136 -138.9923045

226.9718484 47.9053740 -69.1655202 -139.2670983 E 10.0 1000.0 FB 2506 18

Mon

20050404-035033 2.4352842 4.5725447 84.1371636 -107.2552027

236.9175996 44.9164251 -19.7832319 -135.4301528 E 10.0 1000.0 FB 2298

8Eps Mon

20050404-035238 1.2101709 5.1894419 -34.7412788 -116.2396296

214.0140026 56.3130696 -152.5155527 -86.9318369 E 10.0 1000.0 FB 2943

10Alp CMi

20050404-035402 0.0807889 5.7942575 -25.5492894 -120.2127261

182.5184720 61.3904426 -62.2627838 -119.2025719 E 10.0 1000.0 FB 3492

13Rho Hya

20050404-035724 -0.9524950 5.9198336 -126.7231896 -82.4253346

151.8729254 58.6211595 -161.0173677 -125.1356466 E 10.0 1000.0 FB 3915

20050404-040227 -2.0577760 7.2872586 -230.6574206 -107.1600411

126.4679405 50.7424051 -155.5729343 -232.6973369 E 10.0 1000.0 FB 4310

63Chi Leo

20050404-040555 -1.9765225 -0.0400892 -230.9422846 -82.5468702

134.8073834 45.7951699 -199.3907641 -202.0918934 E 10.0 1000.0 FB 4306

62 Leo

65

20050404-041023 -1.3453735 -0.6840786 -153.2776995 -114.1346283

147.4222168 50.1594645 -135.2763945 -170.3353822 E 10.0 1000.0 FB 4119

30Bet Sex

20050404-041207 -0.9431285 -0.4179158 -105.1128564 -114.2736212

156.1789402 52.7614582 -100.9100500 -142.7627071 E 10.0 1000.0 FB 3981

15Alp Sex

20050404-041402 -0.4424744 -1.1862000 -58.5309236 -111.3096296

168.6920921 53.8908302 -67.4711035 -119.3083134 E 10.0 1000.0 FB 3845

35Iot Hya

20050404-041620 -1.9782710 15.3420692 -149.3139911 -234.7262422

118.0892983 57.2370805 153.3712256 -262.5808310 E 10.0 1000.0 FB 4359

70The Leo

20050404-041800 -1.4861274 14.1042475 -103.1636278 -249.8563218

129.7191994 61.4265047 184.2465910 -254.3381097 E 10.0 1000.0 FB 4209

52 Leo

20050404-041903 -0.9721450 13.6370897 -44.7001145 -258.4121554

143.9811680 65.4132661 220.3098995 -245.5255568 E 10.0 1000.0 FB 4035

37 Leo

20050404-042038 -0.3956787 13.9684203 8.1131201 -129.4547968

163.8205213 68.8926294 106.5898092 -123.8927898 E 10.0 1000.0 FB 3866

16Psi Leo

20050404-042232 0.0110661 15.3093022 38.7491853 -165.8733713

180.4899511 70.9268835 110.8888945 -166.1340744 E 10.0 1000.0 FB 3711

66

20050404-042434 0.5493818 15.2701283 60.2408348 -244.2088131

203.2532945 69.4982381 -79.6331665 -249.4769171 E 10.0 1000.0 FB 3510 54

Cnc

20050404-042908 0.5522187 5.9044569 17.9637630 -109.5179452

196.9241667 60.5099939 -18.5302409 -110.5907513 E 10.0 1000.0 FB 3547

16Zet Hya

20050404-043151 -1.0274757 9.2569364 -75.6482290 -109.9221530

147.0417177 61.1745559 -34.2189418 -131.8525130 E 10.0 1000.0 FB 4133

47Rho Leo

20050404-043951 2.5251706 7.3985564 116.0746014 -273.1190917

241.1259570 45.9487147 -173.1575794 -270.8614895 E 10.0 1000.0 FB 2682

20050404-044205 3.0174732 6.2885075 120.0580475 -330.0526884

246.6583421 39.7362194 -227.0630262 -304.5026681 E 10.0 1000.0 FB 2454

20050404-044316 3.4299161 6.9930883 134.3856879 -262.0910312

252.2258159 35.3985664 -154.7974274 -265.6566311 E 10.0 1000.0 FB 2248

20050404-044449 4.1047305 7.4869722 148.7518005 -273.2927509

259.6644983 27.5891991 -157.1306166 -277.5894300 E 10.0 1000.0 FB 1920

20050404-044637 4.5225047 5.0883953 151.2528145 -352.8030935

261.4316536 21.1116382 -217.4096147 -325.6597958 E 10.0 1000.0 FB 1709

20050404-045301 4.5160852 -0.4728325 151.1106048 -331.5002239

256.5862792 17.9352114 -185.1178979 -318.9389861 E 1.0 1000.0 FB 1764

67

20050404-045456 3.9948517 0.9420039 120.5808994 -178.2128939

252.7051348 25.0138473 -73.1222607 -204.7109963 E 1.0 1000.0 FB 2057

20050404-045705 3.4907004 -0.3587889 207.9481606 -354.8908481

246.1532034 30.0299620 -152.0538028 -389.7150644 E 1.0 1000.0 FB 2335

20050404-045849 3.0671180 -1.1907764 189.3947187 -268.2255319

240.3581528 34.1503920 -73.2143767 -322.6972708 E 1.0 1000.0 FB 2572

20050404-050050 4.5542236 15.1853736 273.5719283 -344.4506450

270.9448651 26.2470497 -176.0060452 -404.2593745 E 1.0 1000.0 FB 1809

20050404-050506 5.0955229 14.4875658 289.5623762 -321.5708648

274.7498726 19.1909418 -132.8074309 -407.7423550 E 1.0 1000.0 FB 1600

20050404-050728 3.9933110 14.7108936 291.7423501 -258.2987666

265.6026381 32.9380439 -85.3374770 -375.7573088 E 1.0 1000.0 FB 2159

67Nu Ori

20050404-050946 3.5977301 14.0685517 273.1798592 -345.2515262

261.1867928 37.4594304 -185.3571213 -409.5990186 E 1.0 1000.0 FB 2391

20050404-051108 3.0414396 15.8463872 272.0407194 -312.3067873

257.3287903 45.1915903 -168.1813915 -389.8371905 E 1.0 1000.0 FB 2684 45

Gem

20050404-051317 2.5156941 14.1124850 250.8447381 -336.2283220

248.6602523 50.4141246 -186.0343475 -397.7269198 E 1.0 1000.0 FB 2967

20050404-051519 2.0656630 14.5406519 133.3542989 -295.4828312

242.3191459 55.7553267 -246.6253683 -291.1108436 E 1.0 1000.0 FB 3198

68

20050404-052216 1.5168314 15.2587789 244.7078663 -288.0690765

232.6062920 61.9893631 -48.4943685 -371.7255961 E 1.0 1000.0 FB 3510 54

Cnc

20050404-052353 1.0392266 15.2994172 206.4739090 -203.3431913

220.1844198 66.3150855 134.1734868 -279.4727040 E 1.0 1000.0 FB 3711

20050404-052754 0.6098482 12.9729642 184.9409629 -272.8379631

203.3990072 67.0390494 200.4152065 -317.5212793 E 1.0 1000.0 FB 3896 23

Leo

20050404-052951 0.1287340 14.8860778 161.2952011 -249.3100766

185.5782830 70.4266337 403.2045540 -261.2767473 E 1.0 1000.0 FB 4070 42

Leo

20050404-053143 -0.9721328 15.3391403 90.4527297 -182.6196706

141.8172412 66.8733180 434.9399699 -108.6765586 E 1.0 1000.0 FB 4426 85

Leo

20050404-053450 -2.0425891 17.0084239 -13.0855731 -205.8046533

114.6089493 57.5868307 287.0995856 -137.3112269 E 1.0 1000.0 FB 4801 25

Com

20050404-053622 -2.6900500 13.5818069 -105.7018142 -262.6908381

109.6333975 48.0711306 222.3728472 -239.8107465 E 1.0 1000.0 FB 5013

20050404-053810 -3.6652519 15.2075233 -236.7545870 -144.2347586

96.9432307 37.2406999 2.2295136 -270.1598685 E 1.0 1000.0 FB 5352

69

20050404-054013 -3.5113042 24.9973344 -140.1222403 -264.7928951

86.9512877 43.8058952 260.7410137 -225.5249099 E 1.0 1000.0 FB 5304 12

Boo

20050404-054155 -2.9248722 24.5072947 -58.1262093 -296.9348937

92.5485799 50.8577054 391.2142310 -173.3286096 E 1.0 1000.0 FB 5123

20050404-054415 -2.0811066 24.7665014 20.1590048 -171.0704657

101.1541954 61.3364068 335.4748877 -60.9928160 E 1.0 1000.0 FB 4864

20050404-054550 -0.9768527 25.1371889 167.8706249 -196.6532697

122.1663327 74.3043003 918.2731748 -7.3287068 E 1.0 1000.0 FB 4512

20050404-054800 0.0802264 26.2252711 241.1372443 -272.9022050

187.5698691 81.7777585 1281.8756949 -296.5871423 E 1.0 1000.0 FB 4189

40 LMi

20050404-055032 1.0756898 23.6851922 270.4077590 -250.6288562

237.0055796 72.3359572 -90.9339034 -351.2059535 E 1.0 1000.0 FB 3873

17Eps Leo

20050404-055351 1.8498427 24.3747625 306.5864284 -227.4100917

254.8754091 63.9410342 -145.4886267 -354.3889043 E 1.0 1000.0 FB 3595

69Nu Cnc

20050404-055744 3.0688543 26.6620417 340.0695434 -353.2290668

271.7785947 49.9454202 -326.0847591 -416.0825787 E 1.0 1000.0 FB 3067

83Phi Gem

20050404-055920 4.0652225 25.2818028 347.2695879 -356.6670786

277.5457472 37.0995995 -237.6181762 -435.7413740 E 1.0 1000.0 FB 2569 37

Gem

70

20050404-060059 5.0652836 24.1662622 364.8760221 -373.9973571

283.5322642 24.4315389 -187.6783888 -470.5720742 E 1.0 1000.0 FB 2074

20050404-060300 5.5594937 25.1084492 385.0009588 -260.8141062

287.9479342 19.0028327 -55.7599304 -432.1004982 E 1.0 1000.0 FB 1821118

Tau

20050404-060443 5.5160606 34.6536981 411.8026800 -343.6185185

296.7093561 24.0091061 -173.1661493 -455.7365491 E 1.0 1000.0 FB 1854

20050404-060636 4.8473479 36.1174103 387.7663179 -154.1776446

294.4617872 32.0731410 -33.5673254 -347.8928531 E 1.0 1000.0 FB 2217

20050404-060858 4.0447288 34.3783825 366.3729396 -348.9528725

288.2821371 40.7304597 -312.8595398 -396.2068193 E 1.0 1000.0 FB 2660

20050404-062019 3.3059754 35.3566314 373.0214753 -174.6565418

286.0803937 49.7386414 -153.4132873 -336.4373194 E 1.0 1000.0 FB 3130

20050404-062233 2.0683408 35.2376453 352.3100656 -388.8446953

280.8806895 64.6162434 -820.0191439 -332.7811173 E 1.0 1000.0 FB 3686

20050404-062547 0.9657010 36.5732186 352.2235356 -389.9062983

284.6876586 78.0142305 -2026.0999863 -236.3250924 E 1.0 1000.0 FB 4100

31Bet LMi

20050404-062725 0.1486531 32.9633631 276.7540692 -370.7971624

233.2283798 87.6643928 -3854.1760509 -409.7280804 E 1.0 1000.0 FB 4377

54Nu UMa

71

20050404-063005 -1.0622515 33.2648556 218.1758237 -325.4156514

90.3376094 76.7295793 1522.9975958 128.8293050 E 1.0 1000.0 FB 4784

20050404-063313 -2.0721192 36.1955750 124.8520547 -255.2196609

76.8835806 64.6728436 614.8393819 77.7509485 E 1.0 1000.0 FB 5127 25

CVn

20050404-063503 -2.8889225 36.0811653 55.8521545 -326.5767564

74.4739188 54.8569747 572.2738151 -13.6209650 E 1.0 1000.0 FB 5416

20050404-063644 -3.3240358 32.1954450 -38.1884418 -301.5397777

78.4963549 48.6856378 422.3749008 -119.4355490 E 1.0 1000.0 FB 5569

20050404-063847 -3.1810686 48.6010669 138.8680102 -333.7347351

53.0635240 52.2595793 533.0044945 115.2593091 E 1.0 1000.0 FB 5538 39

Boo

20050404-064034 -2.9708731 44.2921222 140.9827319 -307.9001211

60.1420231 54.6100276 529.3603911 104.4857912 E 1.0 1000.0 FB 5468 33

Boo

20050404-064241 -1.8744205 44.0698928 248.7118952 -345.4751375

57.4455477 66.3144994 719.5851661 259.6796434 E 1.0 1000.0 FB 5116

20050404-064513 -0.9948887 45.3165011 401.9846527 -327.7147415

41.7235006 74.2109656 291.5701864 425.2432128 E 1.0 1000.0 FB 4846

20050404-064758 0.0364510 47.6367303 481.9376924 -396.6100685

358.3937091 76.7387767 -1459.6598219 386.6924639 E 1.0 1000.0 FB 4518

63Chi UMa

72

20050404-065700 0.3085924 44.9670481 422.2186730 -395.9953985

342.8480526 78.8363752 -2135.7242425 271.5801718 E 1.0 1000.0 FB 4486

20050404-065830 0.9746028 45.3871606 452.7378615 -393.4540598

318.9761697 74.3324083 -1872.1390056 8.0123413 E 1.0 1000.0 FB 4280

20050404-070007 2.0392999 45.2776933 468.8864072 -404.7530531

304.3058587 64.3102519 -1095.8007708 -217.5204322 E 1.0 1000.0 FB 3929

20050404-070208 3.0911822 45.5070619 477.6389466 -389.3805496

301.8916327 53.3143153 -663.3386548 -326.7059079 E 1.0 1000.0 FB 3545

20050404-070406 3.6110462 45.5341542 494.4470120 -382.5556651

302.1842816 47.8558842 -531.0330712 -373.3237191 E 1.0 1000.0 FB 3309

20050404-070613 4.1349331 43.8681656 486.5098467 -370.0155842

300.8932630 42.1017519 -402.7074946 -413.0438659 E 1.0 1000.0 FB 3094

20050404-070747 5.1715063 45.0195850 499.0229373 -290.6468314

305.8002665 31.6673155 -190.9398101 -427.0255341 E 1.0 1000.0 FB 2585 16

Lyn

20050404-071056 5.4663791 44.4321597 513.7143228 -369.7999401

306.4142200 28.5152156 -238.9724616 -476.4917879 E 1.0 1000.0 FB 2459

55Psi4Aur

20050404-071625 6.2765672 45.9101503 523.4777161 -184.7545716

311.8328385 21.3496672 7.1897928 -408.2020558 E 1.0 1000.0 FB 2091

35Pi Aur

73

20050404-071806 6.5289486 56.0944461 624.4969995 -161.7885531

322.8215166 23.8995367 11.8590025 -383.7594668 E 1.0 1000.0 FB 1969 26

Cam

20050404-072004 7.2307986 54.3499267 648.2525075 -348.0332872

324.4931391 17.8515320 -75.9017217 -508.2577781 E 1.0 1000.0 FB 1630

20050404-072132 5.7861600 55.3106022 606.8441385 -191.8432237

319.2990695 29.3806829 -79.9864013 -388.6801759 E 1.0 1000.0 FB 2376 7

Lyn

20050404-072628 5.1508780 52.0194464 520.7061301 -407.0635056

313.7140411 33.8545022 -381.4253526 -409.7823084 E 1.0 1000.0 FB 2737

20050404-072835 4.1757372 54.0112739 548.9717189 -436.9896761

314.6338631 42.8304061 -581.9822216 -335.9030512 E 1.0 1000.0 FB 3246

20050404-073011 3.0113348 55.5985486 545.9210851 -448.3528640

318.6949309 52.6239147 -847.9590073 -176.5891893 E 1.0 1000.0 FB 3747

20050404-073139 2.0231103 55.8281003 560.8878082 -442.7677073

325.2516413 60.1403423 -1090.2493547 -19.6093599 E 1.0 1000.0 FB 4112

36 UMa

20050404-073531 1.0959024 54.1998211 579.4369320 -462.0787035

334.8472431 67.0787283 -1403.6283173 169.1844785 E 1.0 1000.0 FB 4427

20050404-073948 0.2127267 55.5535169 596.8587470 -444.2698527

355.0245426 68.7137955 -1069.2891649 399.4519467 E 1.0 1000.0 FB 4745

73 UMa

74

20050404-074150 -0.9732088 54.5311517 485.1816786 -416.3668090

22.3873163 67.4191261 -26.6324258 502.2862665 E 1.0 1000.0 FB 5154 83

UMa

20050404-074356 -1.8974699 53.8770942 392.5491085 -412.9935857

36.9165935 62.1120667 473.9217921 417.9023340 E 1.0 1000.0 FB 5467

20050404-074641 -3.0081801 55.2553194 302.3869244 -346.4696235

41.8398478 52.7397571 478.6877186 256.0067420 E 1.0 1000.0 FB 5887

20050404-074849 -1.4476099 51.2211411 411.1681763 -410.2970536

36.3577861 66.9909041 407.9375124 457.0979574 E 1.0 1000.0 FB 5350

21Iot Boo

20050404-075156 -0.7007006 48.8624703 446.2459413 -432.9590994

25.0912946 73.5612008 -61.4220195 522.6142784 E 1.0 1000.0 FB 5112 24

CVn

20050404-075351 -0.7218057 36.1602453 284.7071587 -378.4114760

75.5254546 80.9885035 2163.8033646 283.0208093 E 1.0 1000.0 FB 5127 25

CVn

20050404-075653 -2.3788041 51.8204650 342.1761162 -398.4838583

44.6314302 59.1227414 584.4762203 336.4488320 E 1.0 1000.0 FB 5715

20050404-082051 -2.8381773 67.0135269 825.7180893 -372.0612756

23.8580943 49.2184592 231.9606324 467.9188036 E -2.0 1000.0 FB 6069

20050404-082244 -2.1197586 64.0710919 673.9204710 -383.2515196

23.4019516 54.5446792 160.4084306 474.0227359 E -2.0 1000.0 FB 5785

75

20050404-082447 -0.6439637 64.2219297 748.7172559 -418.4956198

8.2858048 59.5790978 -388.0401414 491.8845308 E -2.0 1000.0 FB 5291

11Alp Dra

20050404-082740 0.0256661 64.5711997 781.9035952 -451.6993453

359.6712673 59.8097218 -671.9326989 449.0361028 E -2.0 1000.0 FB 5074

20050404-082924 1.0850441 63.6407283 756.6506058 -446.1713361

345.9925898 59.0632460 -970.0584464 249.4742741 E -2.0 1000.0 FB 4727

20050404-083037 1.1068707 63.6387147 835.4139836 -453.4789163

345.7390843 58.9990587 -1039.1896372 235.8224890 E -2.0 1000.0 FB 4727

20050404-083312 2.1854096 64.1794608 809.8133383 -418.6911345

336.2563352 54.1487512 -933.8834458 4.1058178 E -2.0 1000.0 FB 4391

20050404-083938 0.0859124 -0.6571694 122.0691645 -158.8434551

182.2436470 54.9401730 203.6753018 -162.6568861 E -2.0 1000.0 FB 5107

79Zet Vir

20050404-084214 0.2872060 -11.2165461 115.3976302 -155.3251525

185.9011843 44.2184769 138.7324160 -164.5065428 E -2.0 1000.0 FB 5056

67Alp Vir

20050404-084436 -0.9723651 -5.7137131 40.0806582 -160.6901821

158.1835522 47.6043839 129.8320754 -140.5513566 E -2.0 1000.0 FB

5487107Mu Vir

20050404-084716 -1.7811959 -10.1079617 -45.1316181 -148.9840015

145.3920703 38.8017052 40.9024960 -152.1680911 E -2.0 1000.0 FB 5777 37

Lib

76

20050404-092004 0.0445458 35.3784150 350.8457346 -370.9677565

331.3784885 88.8626252 -20642.8311679 207.5646677 E -2.0 1000.0 FB 5361

20050404-092252 0.6788373 34.8594525 358.8457115 -361.0259302

276.1513964 81.6104677 -2511.8920284 -289.6579812 E -2.0 1000.0 FB 5161

20050404-092437 1.2213838 27.7420694 269.3554763 -394.9315545

252.0188474 72.9929224 -826.8650196 -393.2157363 E -2.0 1000.0 FB 4983

43Bet Com

20050404-092754 -0.5565473 40.2489742 345.8150093 -412.9132790

46.0597855 81.1472715 1000.8908836 464.7312228 E -2.0 1000.0 FB 5602

42Bet Boo

20050404-092900 0.7812572 34.8561575 356.0808619 -372.8258599

276.1426562 80.3498318 -2227.3783408 -293.2998986 E -2.0 1000.0 FB 5161

20050404-093111 0.4663308 64.2069192 821.9365785 -472.2422419

353.9405333 59.8684261 -880.4393452 392.8579448 E -2.0 1000.0 FB 5291

11Alp Dra

20050404-093327 1.1252246 64.5593011 840.0217547 -496.1917157

346.3383551 58.1248402 -1030.5424566 281.0022721 E -2.0 1000.0 FB 5074

20050404-093838 2.1061247 69.6081564 1015.2870740 -507.9735402

343.2362039 50.7382968 -953.9769130 132.5618773 E -2.0 1000.0 FB 4787

5Kap Dra

20050404-094318 3.0315473 66.5714478 928.6874382 -500.3085663

334.7049772 48.4394743 -926.0287931 -93.1300693 E -2.0 1000.0 FB 4504 3

Dra

77

20050404-094538 3.7126468 61.5861128 740.2701018 -487.1536772

325.6180289 45.8924832 -788.9525420 -244.3263798 E -2.0 1000.0 FB 4301

50Alp UMa

20050404-094759 5.2867042 62.9266286 791.1152859 -432.9672160

326.9424490 34.9291618 -459.4187283 -418.2114566 E -2.0 1000.0 FB 3757

23 UMa

20050404-095053 6.2084952 64.9618403 929.7736555 -200.4592240

330.9489401 29.5104369 -74.0084458 -436.5327085 E -2.0 1000.0 FB 3391

3Pi 1UMa

20050404-095351 7.1324383 65.4183808 933.2173518 -176.9222946

334.0946113 24.4077680 43.1017190 -424.4822784 E -2.0 1000.0 FB 2975 51

Cam

20050404-095549 7.4863224 66.2772775 974.7100684 -259.1901448

336.1441106 23.0185152 2.7767931 -469.5785176 E -2.0 1000.0 FB 2809

20050404-100930 7.1725210 73.8327125 1358.2167894 -329.2459670

342.4675400 28.2250356 -142.8249567 -484.5852409 E -2.0 1000.0 FB 3075

20050404-101208 5.7574492 74.9696706 1409.9820202 -410.2225564

341.8128910 33.9844112 -442.8309355 -407.8518400 E -2.0 1000.0 FB 3719

20050404-101415 4.6750340 75.5561806 1459.8083030 -467.3902378

342.6608299 38.0856355 -664.0361346 -277.4696770 E -2.0 1000.0 FB 4126

20050404-101607 2.9821716 74.9711350 1446.3769532 -542.4769865

345.2471378 44.2201683 -918.3775846 18.5351499 E -2.0 1000.0 FB 4687

78

20050404-101923 1.2412906 74.4031136 1483.6887765 -536.9332527

352.4882672 48.9548035 -878.5602223 335.4096482 E -2.0 1000.0 FB 5305 3

UMi

20050404-102308 -0.2982477 77.6115283 2065.8752751 -521.8391473

1.3988453 46.7251968 -562.8567982 563.1920768 E -2.0 1000.0 FB 5903

16Zet UMi

20050404-102516 -1.5637494 75.1256339 1554.4785158 -515.9168027

8.7397923 47.7424055 -136.5849628 644.5413986 E -2.0 1000.0 FB 6379

20050404-102826 4.4277639 61.5921536 -458846.6273993 -99802.2866462

324.8150902 40.8280082 1168623.4652658 25600.8211440 E -2.0 1000.0 FB

424 1Alp UMi

20050404-103051 2.9245054 59.3045083 668.0641120 -533.8624864

324.8191694 52.1213686 -1012.5780056 -120.6929127 E -2.0 1000.0 FB 4800

20050404-103325 2.1021629 59.7672728 731.9033297 -514.6290603

330.7750866 57.3611068 -1172.2579397 16.8020153 E -2.0 1000.0 FB 5085

20050404-103459 0.1405461 60.4972983 712.0577891 -508.2801761

357.6442745 63.8487503 -865.6553997 484.2686879 E -2.0 1000.0 FB 5755

20050404-103657 -1.7906358 59.8961439 589.0160637 -479.4183262

26.1626758 59.0727359 282.0089627 543.7577448 E -2.0 1000.0 FB 6511

20050404-103908 2.1974295 59.7700186 725.7132718 -505.2342067

330.0030564 56.7767081 -1137.1261474 -6.9009435 E -2.0 1000.0 FB 5085

79

20050405-031146 1.4990522 -16.7550750 137.5706165 -191.9971015

206.4062509 34.5678665 58.4735265 -227.8242667 E -2.0 1000.0 FB 2491

9Alp CMa

20050405-031845 2.1208836 -6.3253017 218.8270520 -236.1702115

222.6958717 39.4069928 60.6361232 -317.6384221 E -2.0 1000.0 FB 2227

5Gam Mon

20050405-032229 2.6351228 -9.7138431 239.9483361 -238.9572494

227.8119060 32.1516520 44.0965704 -334.1486526 E -2.0 1000.0 FB 2004

53Kap Ori

20050405-032407 2.8679641 -5.9542481 256.7025276 -240.1886494

233.8210668 32.7895578 34.2403154 -349.3678801 E -2.0 1000.0 FB 1899

44Iot Ori

20050405-032541 3.2421097 -8.2464697 264.0664210 -265.0013498

236.7079248 27.3095399 3.0563349 -372.1928923 E -2.0 1000.0 FB 1713

19Bet Ori

20050405-032651 3.1774003 -13.2047125 248.7607705 -216.5203391

232.1700581 24.3402706 38.4224927 -322.9918286 E -2.0 1000.0 FB 1756

6Lam Lep

20050405-032952 3.9171686 -14.3647356 274.0814967 -394.4397331

239.4688339 15.9360764 -113.3735427 -462.8575869 E -2.0 1000.0 FB 1481

53 Eri

20050405-033144 3.8504294 -8.5587625 273.5671864 -338.1930177

243.2945614 20.5708103 -76.7430184 -427.1013611 E -2.0 1000.0 FB 1508 56

Eri

80

20050405-034025 4.5320424 -6.9011944 316.4651143 -424.3233889

251.4211596 13.8466012 -145.1665342 -508.8465168 E -2.0 1000.0 FB 1298

38Omi1Eri

20050405-034326 4.8748604 -3.0156572 331.4589132 -435.3458064

257.7698338 12.0964724 -160.0631634 -524.0393187 E -2.0 1000.0 FB 1212

32 Eri

20050405-034844 4.2318382 -14.3414875 281.8970058 -342.6928450

242.6318217 12.5428811 -82.5255253 -430.7830167 E -2.0 1000.0 FB 1481 53

Eri

20050405-035645 3.4573675 -17.8568864 243.0639551 -267.8952566

231.9937747 18.1778318 -14.7260095 -353.7223136 E -2.0 1000.0 FB 1865

11Alp Lep

20050405-035838 3.0943737 -14.1948600 221.6023080 -198.3359887

230.4549688 24.4013260 35.0817196 -290.6595041 E -2.0 1000.0 FB 2085

16Eta Lep

20050405-040108 2.1728883 -12.0794700 176.8554937 -196.2801519

219.5461448 34.1769804 48.8912066 -258.4674834 E -2.0 1000.0 FB 2574

14The CMa

20050405-040437 0.9832478 -19.2878317 125.7551415 -179.9069804

196.9573720 34.5255730 83.7233693 -204.2181828 E -2.0 1000.0 FB 3192 16

Pup

81

20050405-041909 0.0462210 -12.0291297 72.3911150 -175.8272748

180.9361431 43.5843628 94.4827118 -176.7734528 E -2.0 1000.0 FB 3706 26

Hya

20050405-042211 -0.7511646 -12.4089700 -5.1775033 -166.0268805

165.1209437 41.9998625 41.8638220 -163.1664691 E -2.0 1000.0 FB 3994

41Lam Hya

20050405-042531 -1.5235322 -14.1348178 -75.7474236 -153.6051942

151.9282020 36.8399583 -7.2550529 -170.1686687 E -2.0 1000.0 FB 4289

20050405-042832 -1.6648364 -22.8594286 -133.2053091 -117.1279125

153.8488254 28.0346923 -75.4535907 -156.0599998 E -2.0 1000.0 FB 4343

11Bet Crt

20050405-045812 -1.5283622 -16.3258097 -95.1198360 -133.6248515

152.9190021 34.8003350 -38.6278271 -158.6961769 E -2.0 1000.0 FB 4451

20050405-050214 -1.5570852 -24.7507586 -101.0864640 -106.8362623

156.2010259 26.8488769 -51.8551529 -133.0546705 E -2.0 1000.0 FB 4489

20050405-054525 -0.8343624 -24.7549689 -19.5789021 -114.7114313

166.9083402 29.6817010 7.1504295 -115.9151982 E -2.0 1000.0 FB 4489

20050405-054815 0.2981377 -23.7769031 89.4922658 -109.2044195

184.8101571 31.6863123 86.3147078 -115.0712066 E -2.0 1000.0 FB 4145 44

Hya

20050405-055018 1.2908131 -24.7344667 154.6611275 -132.3593233

199.9583341 28.0928782 104.9431264 -169.3813323 E -2.0 1000.0 FB 3828

82

20050405-055258 2.3940155 -24.6336031 221.9870673 -153.5023673

215.0586837 21.8528920 99.3808024 -236.1982071 E 5.0 1000.0 FB 3381

20050405-055442 3.1524801 -24.8779822 257.0961670 -174.5965172

223.8167451 15.6823351 74.0896892 -282.5234802 E 5.0 1000.0 FB 3045

7Xi Pup

20050405-055624 3.4491993 -24.7223850 269.2383063 -180.5674885

227.0984103 13.1825972 64.1838278 -297.5481753 E 5.0 1000.0 FB 2900

20050405-055823 3.7983024 -10.0109422 272.1880341 -302.1566853

241.5937426 20.1683400 -44.2843882 -401.7934194 E 5.0 1000.0 FB 2732

20050405-060000 2.7561900 -12.6782447 244.3433124 -184.3702420

227.2966187 28.7219041 82.3615425 -292.6067788 E 5.0 1000.0 FB 3259

20050405-060153 0.5764297 -13.6484392 108.3795209 -181.8200818

191.2082150 41.2711386 98.3837890 -196.6971047 E 5.0 1000.0 FB 4123

20050405-060350 2.8203247 -12.6815397 227.6301977 -202.7902519

228.1267197 28.1319924 50.8411276 -297.3961281 E 5.0 1000.0 FB 3259

20050405-060711 -0.4640442 -13.2634733 49.7046009 -177.8183323

170.8819602 41.8973213 96.5894500 -169.6913909 E 5.0 1000.0 FB 4488

24Iot Crt

20050405-061536 -0.3561340 21.2271222 188.5246858 -359.6671423

158.9332303 76.0289420 1170.2009156 -284.3321321 E 5.0 1000.0 FB 4495 92

Leo

83

20050405-061924 -1.5023048 21.1236958 101.7802350 -344.0571140

117.8798597 66.1445193 812.7745626 -139.6342246 E 5.0 1000.0 FB 4894 35

Com

20050405-061944 -1.4966066 21.1236958 101.9360683 -344.0379291

118.0029805 66.2068358 814.4757941 -139.9760709 E 5.0 1000.0 FB 4894 35

Com

20050405-062332 -0.1835512 33.5409033 336.0113588 -201.3047480

109.4431988 87.5665957 6644.2557339 193.8378337 E 5.0 1000.0 FB 4482

20050405-070158 -1.3949816 47.0493050 370.4762652 -406.6751797

44.8446552 69.8134214 623.8936029 427.0356068 E 5.0 1000.0 FB

To observe any trends associated with the above data, a scatter plot of correction vectors

against their prime value (i.e. DEC –v- DEC correction) is shown below.

HA HA Corr Azimuth Alt Az Corr Alt Corr

-3.6653 -236.755 246.769 39.65903 -123.745 -244.199

-1.9765 -230.942 241.6101 45.55984 -65.2322 -160.836

-2.0578 -230.657 237.0836 56.37626 -246.449 -265.688

-1.3454 -153.278 226.9718 47.90537 -69.1655 -139.267

-1.9783 -149.314 236.9176 44.91643 -19.7832 -135.43

-3.5113 -140.122 214.014 56.31307 -15.5156 -86.9318

-1.6648 -133.205 182.5185 61.39044 -62.2628 -119.203

84

-0.9525 -126.723 151.8729 58.62116 -161.017 -125.136

-2.6901 -105.702 126.4679 50.74241 -155.573 -232.697

-0.9431 -105.113 134.8074 45.79517 -199.391 -202.092

-1.4861 -103.164 147.4222 50.15946 -135.276 -170.335

-1.5571 -101.086 156.1789 52.76146 -100.91 -142.763

-1.5284 -95.1198 168.6921 53.89083 -67.4711 -119.308

-1.5235 -75.7474 118.0893 57.23708 153.3712 -262.581

-1.0275 -75.6482 129.7192 61.4265 184.2466 -254.338

-0.4425 -58.5309 143.9812 65.41327 220.3099 -245.526

-2.9249 -58.1262 163.8205 68.89263 106.5898 -123.893

-1.7812 -45.1316 180.49 70.92688 110.8889 -166.134

-0.9721 -44.7001 203.2533 69.49824 -79.6332 -249.477

-3.324 -38.1884 196.9242 60.50999 -18.5302 -110.591

1.21017 -34.7413 147.0417 61.17456 -34.2189 -131.853

0.08079 -25.5493 241.126 45.94871 -173.158 -270.861

-0.8344 -19.5789 246.6583 39.73622 -227.063 -304.503

-2.0426 -13.0856 252.2258 35.39857 -154.797 -265.657

-0.7512 -5.1775 259.6645 27.5892 -157.131 -277.589

-0.3957 8.11312 261.4317 21.11164 -217.41 -325.66

0.55222 17.96376 256.5863 17.93521 -185.118 -318.939

-2.0811 20.159 252.7051 25.01385 -73.1223 -204.711

0.01107 38.74919 246.1532 30.02996 -152.054 -389.715

-0.9724 40.08066 240.3582 34.15039 -73.2144 -322.697

1.95808 47.20731 270.9449 26.24705 -176.006 -404.259

-0.464 49.7046 274.7499 19.19094 -132.807 -407.742

-2.8889 55.85215 265.6026 32.93804 -85.3375 -375.757

0.54938 60.24083 261.1868 37.45943 -185.357 -409.599

0.04622 72.39112 257.3288 45.19159 -168.181 -389.837

2.43528 84.13716 248.6603 50.41412 -186.034 -397.727

2.55978 87.39607 242.3191 55.75533 -246.625 -291.111

0.29814 89.49227 232.6063 61.98936 -48.4944 -371.726

-0.9721 90.45273 220.1844 66.31509 134.1735 -279.473

1.89812 95.38692 203.399 67.03905 200.4152 -317.521

-1.5023 101.7802 185.5783 70.42663 403.2046 -261.277

-1.4966 101.9361 141.8172 66.87332 434.94 -108.677

0.57643 108.3795 114.6089 57.58683 287.0996 -137.311

0.28721 115.3976 109.6334 48.07113 222.3728 -239.811

2.52517 116.0746 96.94323 37.2407 2.229514 -270.16

3.01747 120.058 86.95129 43.8059 260.741 -225.525

3.99485 120.5809 92.54858 50.85771 391.2142 -173.329

0.08591 122.0692 101.1542 61.33641 335.4749 -60.9928

85

-2.0721 124.8521 122.1663 74.3043 918.2732 -7.32871

3.02512 125.5909 187.5699 81.77776 1281.876 -296.587

0.98325 125.7551 237.0056 72.33596 -90.9339 -351.206 2.93057 127.7771 271.7786 49.94542 -326.085 -416.083

2.06566 133.3543 277.5457 37.0996 -237.618 -435.741

3.42992 134.3857 283.5323 24.43154 -187.678 -470.572

1.49905 137.5706 287.9479 19.00283 -55.7599 -432.1

-3.1811 138.868 296.7094 24.00911 -173.166 -455.737

-2.9709 140.9827 294.4618 32.07314 -33.5673 -347.893

4.10473 148.7518 288.2821 40.73046 -312.86 -396.207

4.51609 151.1106 286.0804 49.73864 -153.413 -336.437

4.5225 151.2528 280.8807 64.61624 -820.019 -332.781

1.29081 154.6611 284.6877 78.01423 -2026.1 -236.325

0.12873 161.2952 233.2284 87.66439 -3854.18 -409.728

-0.9769 167.8706 90.33761 76.72958 1522.998 128.8293

2.17289 176.8555 76.88358 64.67284 614.8394 77.75095

0.60985 184.941 74.47392 54.85697 572.2738 -13.621

-0.3561 188.5247 78.49635 48.68564 422.3749 -119.436

3.06712 189.3947 53.06352 52.25958 533.0045 115.2593

1.03923 206.4739 60.14202 54.61003 529.3604 104.4858

3.4907 207.9482 57.44555 66.3145 719.5852 259.6796

-1.0623 218.1758 41.7235 74.21097 291.5702 425.2432

2.12088 218.8271 358.3937 76.73878 -1459.66 386.6925

3.09437 221.6023 342.8481 78.83638 -2135.72 271.5802

2.39402 221.9871 318.9762 74.33241 -1872.14 8.012341

2.82032 227.6302 304.3059 64.31025 -1095.8 -217.52

2.63512 239.9483 301.8916 53.31432 -663.339 -326.706

0.08023 241.1372 302.1843 47.85588 -531.033 -373

3.45737 243.064 300.8933 42.10175 -402.707 -413.044

2.75619 244.3433 305.8003 31.66732 -190.94 -427.026

1.51683 244.7079 306.4142 28.51522 -238.972 -476.492

-1.8744 248.7119 311.8328 21.34967 7.189793 -408.202

3.1774 248.7608 322.8215 23.89954 11.859 -383.759

2.51569 250.8447 324.4931 17.85153 -75.9017 -508.258

2.86796 256.7025 319.2991 29.38068 -79.9864 -388.68

3.15248 257.0962 313.714 33.8545 -381.425 -409.782

3.24211 264.0664 314.6339 42.83041 -581.982 -335.903

3.4492 269.2383 325.2516 60.14034 -1090.25 -19.6094

1.22138 269.3555 334.8472 67.07873 -1403.63 169.1845

1.07569 270.4078 355.0245 68.7138 -1069.29 399.4519

3.04144 272.0407 22.38732 67.41913 -26.6324 502.2863

86

3.7983 272.188 36.91659 62.11207 473.9218 417.9023

3.59773 273.1799 41.83985 52.73976 478.6877 256.0067

3.85043 273.5672 36.35779 66.9909 407.9375 457.098

4.55422 273.5719 25.09129 73.5612 -61.422 522.6143

3.91717 274.0815 75.52545 80.9885 2163.803 283.0208

0.14865 276.7541 44.63143 59.12274 584.4762 336.4488

4.23184 281.897 23.85809 49.21846 231.9606 467.9188

-0.7218 284.7072 23.40195 54.54468 160.4084 474.0227

5.09552 289.5624 8.285805 59.5791 -388.04 491.8845

3.99331 291.7424 359.6713 59.80972 -671.933 449.0361

-3.0082 302.3869 345.9926 59.06325 -970.058 249.4743

4.53204 316.4651 345.7391 58.99906 -1039.19 235.8225

4.87486 331.4589 336.2563 54.14875 -933.883 4.105818

-0.1836 336.0114 182.2436 54.94017 203.6753 -162.657

3.06885 340.0695 185.9012 44.21848 138.7324 -164.507

-2.3788 342.1761 158.1836 47.60438 129.8321 -140.551

-0.5565 345.815 145.3921 38.80171 40.9025 -152.168

4.06522 347.2696 331.3785 88.86263 -20642.8 207.5647

0.04455 350.8457 276.1514 81.61047 -2511.89 -289.658

0.9657 352.2235 252.0188 72.99292 -826.865 -393.216

2.06834 352.3101 46.05979 81.14727 1000.891 464.7312

0.78126 356.0809 276.1427 80.34983 -2227.38 -293.3

0.67884 358.8457 353.9405 59.86843 -880.439 392.8579

5.06528 364.876 346.3384 58.12484 -1030.54 281.0023

4.04473 366.3729 343.2362 50.7383 -953.977 132.5619

-1.395 370.4763 334.705 48.43947 -926.029 -93.1301

3.30598 373.0215 325.618 45.89248 -788.953 -244.326

5.55949 385.001 326.9424 34.92916 -459.419 -418.211

4.84735 387.7663 330.9489 29.51044 -74.0084 -436.533

-1.8975 392.5491 334.0946 24.40777 43.10172 -424.482

-0.9949 401.9847 336.1441 23.01852 2.776793 -469.579

-1.4476 411.1682 342.4675 28.22504 -142.825 -484.585

5.51606 411.8027 341.8129 33.98441 -442.831 -407.852

0.30859 422.2187 342.6608 38.08564 -664.036 -277.47

-0.7007 446.2459 345.2471 44.22017 -918.378 18.53515

0.9746 452.7379 352.4883 48.9548 -878.56 335.4096

2.0393 468.8864 1.398845 46.7252 -562.857 563.1921

3.09118 477.6389 8.739792 47.74241 -136.585 644.5414

0.03645 481.9377 324.8151 40.82801 1168623 25600.82

-0.9732 485.1817 324.8192 52.12137 -1012.58 -120.693

4.13493 486.5098 330.7751 57.36111 -1172.26 16.80202

87

3.61105 494.447 357.6443 63.84875 -865.655 484.2687

5.17151 499.0229 26.16268 59.07274 282.009 543.7577

5.46638 513.7143 330.0031 56.77671 -1137.13 -6.90094

5.15088 520.7061 206.4063 34.56787 58.47353 -227.824

6.27657 523.4777 222.6959 39.40699 60.63612 -317.638

4.17574 548.9717 227.8119 32.15165 44.09657 -334.149

2.02311 560.8878 233.8211 32.78956 34.24032 -349.368

1.0959 579.4369 236.7079 27.30954 3.056335 -372.193

-1.7906 589.0161 232.1701 24.34027 38.42249 -322.992

0.21273 596.8587 239.4688 15.93608 -113.374 -462.858

5.78616 606.8441 243.2946 20.57081 -76.743 -427.101

6.52895 624.497 251.4212 13.8466 -145.167 -508.847

7.2308 648.2525 257.7698 12.09647 -160.063 -524.039

2.92451 668.0641 242.6318 12.54288 -82.5255 -430.783

-2.1198 673.9205 231.9938 18.17783 -14.726 -353.722

0.14055 712.0578 230.455 24.40133 35.08172 -290.66

2.19743 725.7133 219.5461 34.17698 48.89121 -258.467

2.10216 731.9033 196.9574 34.52557 83.72337 -204.218

3.71265 740.2701 180.9361 43.58436 94.48271 -176.773

-0.644 748.7173 165.1209 41.99986 41.86382 -163.166

1.08504 756.6506 151.9282 36.83996 -7.25505 -170.169

0.02567 781.9036 153.8488 28.03469 -75.4536 -156.06

5.2867 791.1153 152.919 34.80034 -38.6278 -158.696

2.18541 809.8133 156.201 26.84888 -51.8552 -133.055

0.46633 821.9366 166.9083 29.6817 7.15043 -115.915

-2.8382 825.7181 184.8102 31.68631 86.31471 -115.071

1.10687 835.414 199.9583 28.09288 104.9431 -169.381

1.12522 840.0218 215.0587 21.85289 99.3808 -236.198

3.03155 928.6874 223.8167 15.68234 74.08969 -282.523

6.2085 929.7737 227.0984 13.1826 64.18383 -297.548

7.13244 933.2174 241.5937 20.16834 -44.2844 -401.793

7.48632 974.7101 227.2966 28.7219 82.36154 -292.607

2.10612 1015.287 191.2082 41.27114 98.38379 -196.697

7.17252 1358.217 228.1267 28.13199 50.84113 -297.396

5.75745 1409.982 170.882 41.89732 96.58945 -169.691

2.98217 1446.377 158.9332 76.02894 1170.201 -284.332

4.67503 1459.808 117.8799 66.14452 812.7746 -139.634

1.24129 1483.689 118.003 66.20684 814.4758 -139.976

-1.5637 1554.479 109.4432 87.5666 6644.256 193.8378

Table 1...Spread sheet layout of HA prime unit and correction

88

HA vs HA Corr

-500

0

500

1000

1500

2000

2500

-6 -4 -2 0 2 4 6 8 10

HA

HA

Co

rr

HA Corr

Arcseconds

fig 27. Scatter plot of HA prime unit v correction

Dec Dec Corr

74.97114 -

542.477

74.40311 -

536.933

59.30451 -

533.862

77.61153 -

521.839

75.12563 -

515.917

59.76727 -

514.629 60.4973 -508.28

69.60816 -

507.974

59.77002 -

505.234

66.57145 -

500.309

64.5593 -

496.192

61.58611 -

487.154 59.89614 -

89

479.418

64.20692 -

472.242 75.55618 -467.39

54.19982 -

462.079

63.63871 -

453.479

64.5712 -

451.699

63.64073 -

446.171 55.55352 -444.27

55.8281 -

442.768 54.01127 -436.99

-3.01566 -

435.346

62.92663 -

432.967

48.86247 -

432.959

-6.90119 -

424.323

64.17946 -

418.691

64.22193 -

418.496

54.53115 -

416.367

53.87709 -

412.994

40.24897 -

412.913

51.22114 -

410.297

74.96967 -

410.223

52.01945 -

407.064

47.04931 -

406.675

45.27769 -

404.753

51.82047 -

398.484 47.63673 -396.61

44.96705 -

395.995

27.74207 -

394.932 -14.3647 -394.44

45.38716 -

393.454 36.57322 -

90

389.906

45.50706 -

389.381

35.23765 -

388.845

64.07109 -

383.252

45.53415 -

382.556

36.16025 -

378.411

24.16626 -

373.997

34.85616 -

372.826

67.01353 -

372.061

35.37842 -

370.968

32.96336 -

370.797

43.86817 -

370.016 44.43216 -369.8

34.85945 -

361.026

21.22712 -

359.667

25.2818 -

356.667

-0.35879 -

354.891

26.66204 -

353.229

5.088395 -

352.803

34.37838 -

348.953

54.34993 -

348.033 55.25532 -346.47

44.06989 -

345.475

14.06855 -

345.252

15.18537 -

344.451

21.1237 -

344.057

21.1237 -

344.038

34.6537 -

343.619

-14.3415 -

342.693

91

-8.55876 -

338.193

14.11249 -

336.228

48.60107 -

333.735 -0.47283 -331.5

6.288508 -

330.053

73.83271 -

329.246

45.3165 -

327.715

36.08117 -

326.577

33.26486 -

325.416

14.48757 -

321.571

15.84639 -

312.307 44.29212 -307.9

-10.0109 -

302.157 32.19545 -301.54

24.50729 -

296.935

14.54065 -

295.483

45.01959 -

290.647

15.25878 -

288.069

12.81993 -

283.778

7.486972 -

273.293

7.398556 -

273.119

26.22527 -

272.902

12.97296 -

272.838

-1.19078 -

268.226

-17.8569 -

267.895

-8.24647 -

265.001

24.99733 -

264.793

13.58181 -

262.691

6.993088 -

262.091

92

25.10845 -

260.814 66.27728 -259.19

13.63709 -

258.412

14.71089 -

258.299 36.19558 -255.22

23.68519 -

250.629

14.10425 -

249.856 14.88608 -249.31

15.27013 -

244.209

-5.95425 -

240.189

-9.71384 -

238.957 -6.3253 -236.17

15.34207 -

234.726

6.303518 -

230.476 -13.2047 -216.52

17.00842 -

205.805

-2.43263 -

205.256

15.29942 -

203.343 -12.6815 -202.79

33.5409 -

201.305

64.96184 -

200.459

-14.1949 -

198.336

25.13719 -

196.653 -12.0795 -196.28

-16.7551 -

191.997

55.3106 -

191.843

45.91015 -

184.755 -12.6782 -184.37 15.33914 -182.62 -13.6484 -181.82

-24.7224 -

180.567

-19.2878 -

179.907 0.942004 -

93

178.213

-13.2635 -

177.818

65.41838 -

176.922

-12.0291 -

175.827

35.35663 -

174.657

-24.878 -

174.597 24.7665 -171.07

-12.409 -

166.027

15.3093 -

165.873

56.09445 -

161.789 -5.71371 -160.69

-0.65717 -

158.843

-11.2165 -

155.325

36.11741 -

154.178

-14.1348 -

153.605

-24.6336 -

153.502

-10.108 -

148.984

15.20752 -

144.235

7.379702 -

142.973

2.379905 -

138.992

-16.3258 -

133.625

-24.7345 -

132.359

13.96842 -

129.455

5.794258 -

120.213

-22.8594 -

117.128 5.189442 -116.24

-24.755 -

114.711

-0.41792 -

114.274

-0.68408 -

114.135 -1.1862 -111.31

94

9.256936 -

109.922

5.904457 -

109.518

-23.7769 -

109.204

4.572545 -

107.255 7.287259 -107.16

-24.7508 -

106.836

-0.04009 -

82.5469

5.919834 -

82.4253

Table 2.. Spread sheet layout of DEC prime unit and correction

Dec vs Dec Corr

-600

-500

-400

-300

-200

-100

0

-40 -20 0 20 40 60 80 100

Dec

Dec

Co

rr

Dec Corr

Arcseconds

fig 28. Scatter plot of DEC prime unit v correction

95

8.3 ASSESSMENT OF POINTING MODEL SCATTER PLOTS

There is an obvious trend in both HA and Dec. The fact that this is not a clean straight

line suggests that there is misalignment on the Polar axis of the Telescope.

If the HA line was non-zero but horizontal, it would suggest an encoder offset or a clock

error. However, as it is sloped, it indicates an alignment problem. A constant but

horizontal Dec error would suggest an encoder offset. The slope indicates an altitude

error in the Polar axis.

Combining the above observations, a correct re-alignment of the axis should improve

the long duration exposure performance of the instrument.

96

CHAPTER 9 - CONCLUSIONS AND FUTURE WORK

9.1 CURRENT PERFORMANCE

At the time of writing, the UWS 24 inch telescope was functioning as a versatile

automated research and educational tool. The majority of the original design goals and

performance parameters have been either met or exceeded. One exception to this relates

to its roboticism. As part of the introduction to this Thesis (page 1) it was stated that one

of the final design goals was to have the telescope robotically controlled over the

internet by a distant observer. Certain policy changes at UWS meant that this final stage

was not completed, in a permanent sense, at the time of writing. However, some robotic

experiments have been made and some internet remote delivery of images has been

undertaken.

9.2 FUTURE WORK

9.2.1 The video system.

The manual video assignment system has proven to be troublesome due to the large

number of sources and destinations available within the observatory. The colour code

system worked satisfactorily for those who were familiar with the system and well

practiced with using it, but seemed unmanageable by infrequent users, particularly those

with limited technical experience. To overcome this problem a microprocessor

controlled video routing matrix needs to be installed. Preferably it would be of the type

where each destination has a control panel from which the desired video source can be

selected e.g. a row of ten push button switches marked CAM 1, CAM 2, MOON CAM

etc. Using this type of system, if a lecturer needs to display moon cam through the

video projector in the lecture theatre he would go to the selector panel adjacent to the

projector and hit ‘moon cam’. This type of system also obviates the need for operators

to return the system to a default condition.

97

A further enhancement would be the inclusion of a ‘salvo take’ function whereby a

frequent user could set up the complete matrix to his standard configuration with one or

two key strokes.

9.2.2. Robotics.

The UWS telescope is currently able to be remotely controlled over the net by a distant

observer. Processes such as image download, viewing session scheduling and

prioritising, automated billing for viewing sessions, and automated logging still need to

be addressed to lift the facility to its fullest potential as both a viable entity and scientific

tool.

98

REFERENCES

Allen, C.J., 1973 Astrophysical Quantities, University of London, Althone Press.

Bok, B.J.,1955 Size and Type of the Telescope for a Photoelectric Observatory, the

Astronomical Journal, 5:27

Baruch, J.E.F.,1992 Robots in Astronomy, Vistas in Astronomy 35.

Boyce, J.S.,1998 Servo Statistics, R.S. Data Library, RS Components Ltd, Northants

UK.

di Cicco, D., 1992 The ST-6 CCD Imaging Camera, Sky and Telescope, October , p395.

Dynaserve Corp.,2003 Dynaserv Installation Manual, California, USA.

Elliott, K.H., and Eyles, C.J.,1987 The University Telescope and Observatory, Journal

of the British Interplanetary Society, v.40, p195-200.

Genet, Russell M., Hayes Donald S., et all,1998. Robotic Observatories:a Handbook of

Remote Access, Personal Computer Astronomy. Autoscope Corp., Mesa, Arizona.

King, H.C.,1955 The History of the Telescope, Sky Publishing Corporation, Cambridge,

Massachusetts.

Levy, V., James, G., Halim, Z., & Baruch, J.E.F.,1993 The Development of Inspiration

in the Classroom, In Press.

Maran, S.P.,1967 Telescopes and Automation, Science 158, p867-871.

Martin, R., and Hartley, K.,1985 Remote Observation of Telescopes from the United

Kingdom, Vistas in Astronomy 28, p555-560.

Max, Claire,2003 Adaptive Optics for Extremely Large Telescopes, UC Santa Cruz.

McConnell, Anita,1992 Instrument Makers of the World, Troughton and Simms, York.

Mitchell, E.W.J.,1989 A Plan for Research in Astronomy and Planetary Science by

Ground Based Techniques, Serc Swindon I.S.B.N. 1-870669-10-X.

Reddish, V.C.,1966 Sky and Telescope 32: 27

Ridpath, I. (Ed.) 1991 Norton’s 2000.0 (18th edition) Bath Press.

Trueblood, Mark and Gennett, Russell, 1985 Microcomputer Control of Telescopes,

Willman-Bell, Richmond, Virginia.

99

APPENDIX “A”. ACE CONTROL SYSTEM EXTRACTS

System Overview.

The control system utilizes two computers, one called TELSECOPE and one called

CAMERA. The camera can either be operated in stand-alone mode or, preferably,

through the telescope computer.

This manual described the ACE Control System software which controls the telescope,

observatory, and cameras.

The computers should be left powered up so that remote access is available to the

system at all times.

Remote access is available through vnc (Virtual Networked Computers) and a free

version can be downloaded to your computer (www.realvnc.com). Your remote

computer can be a Windows®, Linux or SunOS® workstation.

.

Logging onto ACE.

A user name and password are required to log onto ACE.

There are three levels of User access.

User Level Typical User Comment

1 Minimal Access Suitable for student / public access

2 Standard Unable to build a new pointing model and other

100

Observer engineering functions. This should be the

normal observing level.

3 System Engineer Full access to engineering system functions.

This level restricted to a few fully trained staff.

The Observatory Manager will issue users with a Logon

name and password. When you have finished using the

telescope please log out (using the menu User->Logout).

Please note that this is a dedicated telescope control

computer. Users are not expected to play computer

games, download music, etc., which can slow down the

computer and interfere with the telescope controller.

Please use your own computer for such activities!

101

The ACE main window.

The background of the main window is split into three logical areas.

The left side of the screen shows the current status of the DOME and TELESCOPE .

Many of the fields are color coded according to a standard traffic light where:

RED = STOP Something is stopped, closed, or not ready.

YELLOW =

CHANGE

Something is about to change or at a home position

GREEN = GO Ready. All boxes should be green (or yellow) when

observing

Therefore, one can tell at a glance that the dome and the telescope tracking are not ready

in the window below:

102

The right side of the screen shows the position of the telescope and various clocks. All

this information is written to the image FITS headers together with a host of observatory

and instrument settings.

103

Object Acquisition

The center part of the screen deals with object acquisition.

To open a catalog right-click the mouse anywhere on the screen to access a pop-up

menu:

Select Open database and chose either a standard or custom catalog. ACE_BSC5.cat is

a modified copy of the Yale Bright Star Catalog version 5.

104

Scroll through the database then select the desired object by double-clicking on the

object name.

This will load the object into the green entry boxes denoting a (RA, DEC) coordinate

system.

The database fields can be sorted (in ascending or descending order) by clicking on the

desired header.

The bright star catalog defaults to being sorted by magnitude. If, for some reason, you

wanted to have a catalog default to being listed in ascending order of declination simply

sort the file that way and save it. The next time it is loaded it will list in that sort order.

Database Filtering

105

To filter a catalog right-click the mouse anywhere on the screen to access a pop-up

menu:

In the example below all objects greater than RA 22h30m and less than RA 06h00 will

be selected.

If the database is saved with the filter applied then only those objects that pass through

the filter will be saved. This is a convenient way to make sub-catalogs. Save the

database using the pop-up menu.

106

NOTES

107

Objects can also be entered manually using the keyboard. Click on the 0 button to clear

the fields. This will place the cursor in the Name box. If the name box is left empty the

control system will assign the name (RA, DEC) with values according to those fields.

Data can also be sent to ACE from any ASCOM enabled application, such as Megastar,

TheSky, Computer Aided Astrometry (for NEO searches) and similar commercial

software packages. ACE offers a Robot Extension which permits pre-scripted

observations with automated observatory open / close procedures.

Data can be entered as RA(HH MM SS.s or HH MM.m) and DEC (DD MM SS.s or DD

MM.m).

However, upon pressing the GoTo button the system will check data entry and convert

to the standard format for saving in the catalog. The ACE system automatically checks

data entry as it is typed, to prevent incorrect input.

108

Three different Style Tabs are available, R.A., Offset and H.A.

The R.A. tab has green colored entry boxes and is the default setting.

109

The Offset tab has yellow colored entry boxes with red text.

Offsets can be in arc_seconds or in (seconds of time, arcseconds).

The H.A. tab has orange colored entry boxes. Moves in this mode park the telescope at

the desired position and turn the drives off.

One the data has been successfully entered click on the GoTo to move the telescope. A

confirmation dialog is issued, the appearance and color coding changing depending on

the style tab.

110

111

When the telescope starts to slew to the object the GoTo button is replaced by a

CANCEL MOVE button and a pair of progress bars (denoting H.A., DEC) that report

how far the telescope has left to move.

Finally, there is a series of up to three “Most Recently Observed” buttons for each tab

field. In the example above there is only one button as this was the first move of the

night.

Simply double-click on the button to re-send the telescope back to that object.

112

113

MENUS

The menus and the associated toolbars give access to a host of other services. The

menus vary depending upon factors such as the User Level, the equipment installed, and

the type of telescope.

The User menu

Allows user LogOn and LogOff and exit of the application. At the end of an observing

session the user should LogOff. Alternatively, LogOff and exit ACE. Either of these

operations will turn power off to all the motors and leave the system in a safe storage

condition.

The Setup Menu is primarily used by the SystemEngineer and is discussed in Appendix

A.

The Observatory Menu

If a weather station is installed the current data can be displayed using this menu.

The Dome Menu

114

The dome looks after itself if AutoDome is selected. The status boxes on the main

screen turn green.

To manually control the dome the following functions are available:

DomeöHome

To moving the dome past the home sensor will reset the

encoder azimuth. To go past home and reset use HOME

AZIMUTH. To place the dome at the sensor use PRECISE

SEEK ON DOME SENSOR which will taken longer to

complete.

DomeöAzimuth

To manually move the dome to a specified

azimuth enter the value in this dialog.

115

DomeöReset Encoder

This dialog should not have to be used. If

there is a problem with the azimuth

encoding simply pass home. The system

remembers all data even during a power

loss.

Please note that if the dome is on the home sensor this dialog will have no effect

because the dome azimuth is reset to home when at home.

DomeöOpen Shutter

DomeöClose Shutter

The Open and Close functions permit one or both

doors to be operated.

When opening the main shutter must be fully

opened before the lower shutter can be operated.

When closing the lower door must be fully closed before the main shutter can be

operated.

116

DomeöSmartDome

When used in conjunction with an ACE SmartDome™ the software constantly polls the

status of the SmartDome™. In the event of a prolonged communications failure the

some will automatically close. It will also automatically close if the rain-snow sensors

are enabled and activated.

117

The Telescope Menu

Access these functions from the Menu or from the Toolbar.

TelescopeöSoftPaddle…

Displays the ACE SoftPad™ which is a screen-based hand

paddle. The physical hand paddle reads the software paddle

settings.

There are three fundamental settings in the hand paddle, called

Guide, Set, and slew. For safety reasons slew is only available

118

with the physical hand paddle, located in the dome, or by using the GoTo button in the

main ACE software window.

The settings are adjustable by the System Engineer, and are typically 1 to 25

arc_seconds/second for guide and 50 to 1000 arc_seconds/seconds for guide. Use the

slide bars to select the desired guide and set speeds. If you always want to use the same

settings the Lock button will simplify the dialog.

The four black buttons represent the cardinal directions N, S, E, W. It is also possible to

select two-axis moves, NW, NE, SE, SW. Simply press and hold down the left mouse

button over the desired button. Moving the mouse over a different button will

automatically change to that direction. The current direction is shown in the box located

at the center of the black buttons.

The telescope focus has similar settings, called fine, coarse and slew. The focus value is

displayed in several locations including at the bottom of the hand paddle.

Finally, the slider bar at the top of the dialog is used to adjust the slew speed of the

physical hand paddle. Most observers cannot react as quickly as the computer and so

the slew speed of the telescope can be changed from 20% to 100% of the computer slew

speed, with 80-% being the default.

119

TelescopeöZenith Park

TelescopeöStow Telescope

TelescopeöDomeFlatPark

The park utilities all have the same properties, namely moving the telescope to a fixed

(HA,DEC) and turning off the drives.

Zenith Park is used before closing the mirror petals on the Pomona Telescope because

this telescope has a special condition that the petals can only be opened or closed when

within 5 degrees of the zenith.

Stow Telescope is used to park at some other pre-determined position. This might be

required for filling a dewar, etc.

DomeFlatPark is used to align the telescope so it is pointing at the flat field screen,

positions the dome at the correct azimuth, and opens the mirror petals.

TelescopeöOpenMirrorCover

TelescopeöCloseMirrorCover

Special case for Pomona Telescope where the telescope must be at an altitude > 85° for

the covers to open. All other telescopes can open without restriction. Typical open /

close time < 15 seconds.

TelescopeöResetEncoders

For use on telescopes with incremental encoders.

120

Software limits resetting to (RA, DEC) when tracking or (HA, DEC) when not tracking.

If the encoders are reset by more than 1 degree then a warning is issued before resetting.

The coordinates are picked up from the last GoTo move but can be edited if necessary.

Under normal circumstances you should not have to reset the encoders. Check the

pointing model is turned on and that there are sufficient grid points in the model. If not

add the current knbown position to the model.

121

TelescopeöFocus

The telescope focus tool is another floating dialog

that can be used to move the focus ram to pre-

selected positions.

The current focus is read out at the top of the box.

Pressing the Go To Focus button will move the

ram to the absolute value shown in the green edit

box.

For telescopes with multiple instruments up to

four pre-determined values can be stored, and

named, using the Setup function. In this example

there are four instruments called S2KB, Moasaic, Eyepiece, and Port 4. Pressing on one

of these buttons will load the preset value into the green edit box.

AutoFocus is for cameras connected to the ACE Control system and permits automated

focus adjustments.

Incremental manual focus adjustments can be made using Jog+ and Jog- buttons which

moves the ram by the number of counts entered in the yellow box.

Drive to Zero moves the ram all the way out (maximum distance between mirrors) and

resets the encoder to zero. Drive to Max moves all the way to the maximum focus limit.

STOP can be used to quit motion when the telescope is almost in focus. The Backlash

button is used to remove lead-screw backlash. Servo is used to keep the focus ram at

the same counts as the telescope moves. It is currently only used at a retrofit telescope

at Kitt Peak National Observatory.

122

Change With Filters allows the focus ram to be automatically moved as the filters are

changed. Once a given filter has been focused use the Bias button to set the filter zero-

point. Then use the Filter Offset button to establish offsets for the other filters when

they are in focus. This procedure only needs to be performed each time new filters are

installed.

TelescopeöTrackEnable

Toggles the tracking on/off.

A warning is issued.

123

TelescopeöTrackRates

The telescope track rates can be changed using

this dialog.

Nominal values are 15.0000 ±3.0000

arc_seconds/sidereal second but larger values can

be entered if so desired.

In declination the nominal rate is 0.0000 ±3.0000

arc_s/s.

Again the rate can be increased by the System

Engineer (it is set at this nominal rate to prevent large data entry errors).

Custom rates can be saved for later retrieval.

Finally, it is possible to superimpose Solar System rates. Enter the rates of the NEO or

other object and these will be added to the base tracking rates.

The Track Enable button will change the tracking state if it is currently different to the

requested value.

TelescopeöCenter CCD

124

Used in conjunction with the

CCD Camera Interface. The

user clicks the mouse on the

desired object to be centered.

That (X, Y) value is entered into the edit box. Pressing

Center Star will move the telescope to place that object at

the center of the CCD.

The Setup button expands the dialog for changing the basic

scaling parameters . Up to two different CCD’s can be

stored.

125

The Instruments Menu will vary depending on the current equipment installed.

InstrumentsöFilterWheel

The ACE Dual wheel has two stacked wheels so in most circumstances, to observe

through just one filter, the un-used wheel is set to the empty position. Up to four wheels

are currently accommodated.

126

The Video Cameras permits up to eight cameras to be switched and either a single

camera, the first four cameras, or the last four cameras to be displayed. It addition it is

possible to turn on low-wattage camera lights.

ObservationsöSetup; ObservationsöSimple; ObservationsöSequence

Use the setup menu to put in the

observer names and any

temporary notes like “non-

photometric”.

Then select the directory and

name structure for the images.

The image numbers are

automatically incremented.

127

Take single exposures using the

Simple dialog

Real-time feedback is available.

The report box changes color

where yellow is idle, green is

exposing and the image will be

saved, and red is exposing and the

image is not saved.

128

When the system is not in auto-

save mode the SAVE button

becomes available. You can save

an image at any time.

129

Finally, for sequences it is possible to have multiple filter observations. Sequences can

be saved or recalled. Variable or fixed binning permits a complex set of observations to

be taken.

The observatory can be closed after the observations are completed.

For more complex observations requiring multiple objects through multiple filters the

ACE Robotic Control extensions are used. The ACE telescope has a robotic library

which is ASCOM compatible.

130

Appendix A: System Engineer and the Setup Menu

The System Engineer is able to change the fundamental operating parameters of the

telescope. Access to these functions are password protected and only fully trained

persons should attempt to alter parameters. If there is a problem with the setup

parameters please contact ACE for assistance before making changes.

The number of menus that appear depends on the User Level. The appearance for a

normal observer is shown below.

131

SetupöEngineering Services…

Prevents a remote user from operating the system when the telescope is being serviced.

It is also possible to set the hand paddle

velocities to a fractional custom level so the

operator can limit the maximum slew rate

while operating overhead cranes, etc, during

instrument changes or top-end secondary

changes.

Press Exit Engineering Services to exit the dialog.

SetupöSystem Parameters…

This menu gives access to a complex series of tabbed dialogs to set fundamental

parameters of the telescope, such as longitude, latitude, encoder ratios, and other

features which the regular user cannot change.

The menu is password protected and brings up the following dialog:

132

The contents of the setup dialogs are shown here for reference only. Complete details

are in the Technical Reference Manual. Some information is taken from these files and

written to the image FITS headers.

133

134

The values in the ACE SoftPad™ are also read by the physical hand paddle.

135

Mirror Cover Park was designed for telescopes without automated covers. For

telescopes with fully automated covers the option does not appear in the telescope park

136

menu. Flat Field Park is for aligning the telescope and dome with a calibration screen.

Stow Telescope is for a standard home position.

137

The software handles an offset-axis telescope and the telescope being offset from the

dome center.

138

If the DAYLIGHT SAVINGS field is left empty the system will always report standard

time.

This dialog controls access to the setup menus and enables or disables the User Logon

feature.

139

This dialog is used with telescopes having incremental on-axis encoders. It is not used

for absolute encoders systems.

140

SetupöEquipment Installed…

Another password-protected series of tabbed dialogs that with auxiliary instrumentation.

Only those dialogs relevant to your system are shown here.

141

142

SetupöControlCardöVersion

Reports the revision number of the telescope motion control card.

SetupöControlCardöControl Card Diagnostics

The first dialog, AXES PARAMETERS, reports low-level motor and encoders counters

registers, limit switches, home sensors, current velocity, direction and other card

parameters. Used by the System Engineer as a diagnostic tool.

The second dialog, Control InOut, reports the low-level status of the digital i/o bits. The

Names button permits customization to suit the hardware installed.

143

144

SetupöControlCardöAbsolute Encoders

This is another diagnostic tool. It shows the absolute encoder

counts. The encoders have 8192 pulses per revolution and up

to 4096 revolutions. Image capture shows the H.A worm at

5300 pulses on rotation number 12. Telescope is therefore in

the west (positive rotation) at 95412 total counts and

declination is North by 174811 counts. The H.A. worm is

5300/8192 of the way through its rotation. This can be used

to map out periodic errors.

The zeropoints should be at 0. If not, press ResetZeropoints.

When the telescope is tracking the HourAngle encoder should be constantly increasing.

This tool is a easy way to check encoder functionality.

The ACEFlex™ Pointing Model.

The ACE Control System uses a grid map to determine the pointing corrections. This

has distinct advantages to alternative methods based on mechanical and optical

modeling of the telescope. First, he grid point method is independent of the telescope

and hence the same technique can be used for all telescopes. Second, the grid point

model is able to learn in real time and as more points are added the system is capable of

extremely high accuracy.

145

The ACEFlex™ pointing model uses a series of grid points, fixed in (HA, DEC) or (AZ,

ALT), which are randomly scattered around the sky. Although the positions of the grid

points is random, a spacing of about 5 degrees on average, around the whole sky, will

yield optimal results. Corrections are stored for each grid point and the model takes into

account mechanical mount flexure, tube flexure, bearing errors, polar misalignment

errors and refraction as a function of temperature and atmospheric pressure.

Depending on the grid density and the position of the target a 1, 2, 3 or 4 neighboring

grid points will be used in the model. Under normal circumstances 5 neighbors are

used.

How to apply a Pointing Model.

You must have a sufficient User Level privileges to apply a model. Otherwise the menu

option will not be available.

SetupöACEFlex Pointing ModelöApply Model displays the following dialog:

146

Under normal circumstances the

user does not need to enter this

dialog. It is possible to select

different models depending on

the instrumentation installed.

Also, as more points are added to

the grid it becomes more

efficient to decrease the search

radius around the target star. A

distance-weighted solution will

bias the correction to apply more

weight to the closer grid points.

The temperature and pressure are

stored for each grid point. The

current temperature can either be

read by the weather station (if

installed) or manually entered

(which is the main reason an

observer might want to use this dialog). Finally, the number of elements in the

ephemeris is used to calculate the position of the telescope as a function of time. If an

auto-guider is used the ephemeris is ignored, otherwise the telescope positions are

corrected to match the ephemeris.

147

How to create a Pointing Model.

You must have a sufficient User Level privileges to create a model. Otherwise the menu

option will not be available.

SetupöACEFlex Pointing ModelöApply Model displays the following tabbed

dialogs:

The Grid Point Selector is used to find suitable grid-point stars. To use this dialog first

open a catalog using the Pointing Map Star Catalog button. The catalog ACE_BSC5

should be used. This is a formatted copy of the Yale Bright Star Catalog #5. The name

of the catalog appears in the green edit box.

Next select a candidate grid point in terms of (HA, DEC) or (Az, Alt). For an

equatorial telescope we suggest using (HA, DEC) and when building the model to make

rasters in HA at different declination bands, typically, 0, 10, 20, 30, etc and then come

back and fill in at band 5, 15, 25, etc.

The screen capture shows a selection at (HA=4, DEC=30) using all stars down to 8th

magnitude within a radius of 5 degrees of the grid point. A total of 19 stars were found.

The stars are then listed in magnitude order. To select by distance from the grid point

148

select the Angle header. Double-click on the desired star name and the selection will

appear at the right side. Warning: Clicking on the GoTo button will move the telescope

without further prompting. As you have System Engineer status we assume that you

know what you are doing and have removed “annoying” reminder dialogs.

Once the telescope has arrived at the destination take an image, then use

TelescopeöCenterCCD to calculate the residual correction. Once the telescope has

been centered it is time to save the grid point.

Click on the ACEFlexDatabase tab to select the other tabbed dialog. If a flex map is

not open click on Open FlexMap to open an existing file or create a new one. The

name of the catalog appears in the green edit box. Then use the Star Centered? Click

to ADD button to add the new grid point. Grid points have a unique ID based on the

U.T. Date and the UT Time. To remove a grid point highlight that point and click on

the Delete button. The total number of grid points is also shown.

The database also keeps track of the current observer so that points can be removed

based on date, observer and other parameters.

A screen capture showing the construction of a pointing model.

149

150