The cold is not a problem for the Fluke 189 DMM, seen here with the Antarctic Fibre-OpticSpectrometer.

Fluke DMMS inAntarctica

Astronomers from the Universityof New South Wales (UNSW) inAustralia have been working inAntarctica’s interior since 1996.In collaboration with astronomersfrom France, Italy and the UnitedStates, they’re seeking the perfectlocation for the next generation ofdeep-space telescopes.

Most established Antarctic sci-ence bases lie on or near thecoast. Few are located in theinterior, given how high, feature-less and difficult it is to reach.During the sunless winter, tem-peratures in the interior fall downto minus 80 Celsius or lower.

For the purposes of astronomi-cal “seeing”, however, theAntarctic interior is ideal. In fact,Australian astronomers have suc-cessfully demonstrated that theirsite 1000 km from the Antarcticcoast has seeing conditionsnearly as good as the orbitingHubble Telescope. The site lies at75 degrees south latitude and3260 meters above sea level. Acollection of odd-shaped build-ings there house the new era interrestrial astronomy.

Multimeters for installa-tion and maintenanceBecause the astronomers canonly get to the Antarctic interiorduring summer, their automatedtelescope equipment must oper-ate unattended the rest of theyear, reliably producing accuratemeasurements. The equipment isa custom mixture of analog anddigital electronics developed towithstand the extreme and vari-able winter temperatures.

A key part of the tool kit usedto install and maintain theseelectronics have been the Fluke189 and 179 digital multimeters(DMM).

During their brief summer trip,the astronomers rely on the FlukeDMMs to update their instrumentsand repair any faults thatoccurred during the winter. Then,they leave several Fluke DMMson site to monitor operations intheir absence.

Using the Fluke 179 DMM to test an instrument on the observatory roof.

Technology at Work

2 Fluke Corporation Fluke DMMs in Antarctica

Complex equipment andoperationsTo evaluate the site’s long-termpotential, the south pole teamhas installed two robotic tele-scopes weighing 70 kg each. Thetelescope engines use jet fuel togenerate electric power, and thesystem is run by a microprocessorcontroller. Overall, the electronicsuse only 20 watts of electricity.With no heating, the systemswork at ambient temperaturesdown to minus 80 Celsius

Designed at UNSW, theAntarctic Fibre-OpticSpectrometer points at brightstars, planets and the moon andsends the light down two bun-dles of optical fibers. Thespectrometer’s signal, measuredwith a CCD camera, indicates thetransparency of the Earth’satmosphere from ultravioletwavelengths to the visible red.

The Antarctic DifferentialImage Motion Monitor is a tele-scope based on 14-inch optics,used to measure the astronomicalseeing in the visible spectrum, ie.how much atmospheric turbu-lence affects the quality of theimages. This was developed bythe Australian National Universityin the national capital ofCanberra.

In the future, the site couldhost major new astronomical tel-escopes, from 2 to 100 meters indiameter. Building a large terres-trial telescope in Antarctica costsa lot less than the Hubble’sUS$3.5 billion outlay.

Testing proceduresDuring trips to Antarctica eachsummer, the researchers use theirDMMs to test and set up theastronomical instruments andsupporting electronic and electri-cal systems. Typically, thisincludes voltage, resistance andtemperature measurements. TheDMM is used successfully in out-door ambient temperaturesgenerally between minus 30 tominus 40 Celsius; indoors, about10 degrees.

As UNSW astronomer MichaelAshley explains it, the teamchose the Fluke 189 DMM basedon its features and facilities,including basic accuracy, the dualdisplay, wide range of measure-ments and stand-alone logging.The astronomers regularly usethe data logging and averagingfeatures. The ability to setup theinstrument and leave it operatingunattended, gathering data forseveral hours, is a big advantagefor Ashley.

The team keeps a 189 DMM atthe south pole site year round.Even after withstanding minus80 degrees Celsius, “it works finewhen we come back each sum-mer,” says Ashley.

The team also used two 189DMMs to log the performance ofgel cell batteries during the origi-nal equipment development.“One DMM logged battery chargeand discharge current, while theother logged battery voltage. Wethen made a series of measure-ments over several weeks while

maintaining the batteries at vari-ous temperatures from 20 tominus 60 Celsius. The datalogged by the 189s were down-loaded to a PC for plotting andanalysis,” explains Ashley.

“From experience, we’ve foundcheap multimeters are susceptibleto radiofrequency interference,when used near switchmodepower supplies for example. Andtheir accuracy suffers as theirbatteries decline, as well as hav-ing other display accuracyproblems.”

“We need instruments thatwork, from which we can guar-antee results. We’ve never had aproblem with Fluke instruments,”says Ashley.

The site is cold and dry, with little wind or seismic activity and fewcloudy days. Little wind means steady telescopes. High altitudemeans there’s less distorting atmosphere to look through, and lowmoisture levels means less radiation from the universe is absorbed.Low temperatures make for darker skies in the infrared range. TheUNSW experiment is in the green and gold structure in the fore-ground (photo: E. Aristidi).

According to the DMM it’s minus 32.5 Celsius in the telescope mount!

Fluke CorporationPO Box 9090, Everett, WA USA 98206

Fluke Europe B.V.PO Box 1186, 5602 BD Eindhoven, The Netherlands

For more information call:In the U.S.A. (800) 443-5853 or Fax (425) 446-5116In Europe/M-East/Africa (31 40) 2 675 200 or Fax (31 40) 2 675 222In Canada (800) 36-FLUKE or Fax (905) 890-6866From other countries +1 (425) 446-5500 or Fax +1 (425) 446-5116Web access: http://www.fluke.com

©2005 Fluke Corporation. All rights reserved.Printed in U.S.A. 1/2005 241817 Pub-ID 10901-eng

Fluke.Keeping your worldup and running.