Astrology Notes 12

8/2/2019 Astrology Notes 12

1/23

vernal equinoxn.1. The point at which the ecliptic intersects the celestial equator, the sun having a northerly motion.2. The moment at which the sun passes through the vernal equinox, about March 21, marking thebeginning of spring in the Northern Hemisphere.

vernal equinoxn1. (Earth Sciences / Physical Geography) the time at which the sun crosses the plane of the equatortowards the relevant hemisphere, making day and night of equal length. It occurs about March 21 inthe N hemisphere (Sept. 23 in the S hemisphere)2.a. (Astronomy) Astronomythe point, lying in the constellation Pisces, at which the sun's eclipticintersects the celestial equatorb. (Astronomy) the time at which this occurs as the sun travels south to north (March 21)

celestial equatorn.A great circle on the celestial sphere in the same plane as the earth's equator. Alsocalled equinoctial, equinoctial circle

(Astronomy) the great circle lying on the celestial sphere the plane of which is perpendicular to theline joining the north and south celestial poles Also called equinoctialequinoctial circle


2/23


3/23


4/23


5/23

Equinox

An equinox occurs twice a year, when thetiltof theEarth's axis is inclined neither away from nor towards

theSun, the center of the Sun being in the same plane as the Earth's equator. The term equinoxcan also

be used in a broader sense, meaning the date when such a passage happens. The name "equinox" is

derived from the Latin aequus(equal) and nox(night), because around the equinox, the night and day have

approximately equal length.

At an equinox, the Sun is at one of two opposite points on the celestial spherewhere thecelestial

equator(i.e. declination 0) and intersect. These points of intersection are called equinoctial points:

classically, the vernal point and the autumnal point. By extension, the term equinoxmay denote an

equinoctial point.

An equinox happens each year at two specific moments in time (rather than two whole days), when there is

a location (thesubsolar point) on the Earth's equator, where the center of the Sun can be observed to be

vertically overhead, occurring around March 20 and September 22 each year.

Although the word equinoxis often understood to mean "equal [day and] night", this is not strictly true. For

most locations on earth, there are two distinct identifiable days per year when the length of day and night

are closest to being equal; those days are referred to as the "equiluxes" to distinguish them from the

equinoxes. Equinoxes are points in time, but equiluxes are days. By convention, equiluxes are the days

where sunrise and sunset are closest to being exactly 12 hours apart.[2][3]

Date

WhenJulius Caesarestablishedhis calendarin 45 BC, he fixed the Spring equinox on March 25. The

reasons of the actual shift toMarch 21are linked to the goal followed byPope Gregory XIIIto create

his modernGregorian calendar. In fact, the Pope was not moved by the desire to honor theRoman

emperor, but to restore the edicts about thedate of Easterof theCouncil of Nicaeaof AD 325.

Incidentally, the date ofEasteritself is fixed by an approximation of lunar cycles used in the Hebraiccalendar, but according to the historianBedethe name comes from a pagan celebration by the

Germanic tribes of the vernal (spring) equinox. So, the shift in the date of the equinox that occurred

between the 4th and the 16th centuries was annulled with the Gregorian calendar, but nothing was

done for the first four centuries of the Julian calendar. The days of February 29 of the years AD 100,

AD 200, AD 300, and the day created by the irregular application ofleap yearsbetween

theassassinationof Caesar and the decree ofAugustusre-arranging the calendar in AD 8, remained

in effect, and moved the equinox four days earlier than in Caesar's time.

[edit]Names

Vernal equinox and autumnal equinox: these classical names are direct derivatives of Latin

(ver= springand autumnus= autumn).
http://en.wikipedia.org/wiki/Axial_tilthttp://en.wikipedia.org/wiki/Axial_tilthttp://en.wikipedia.org/wiki/Axial_tilthttp://en.wikipedia.org/wiki/Earthhttp://en.wikipedia.org/wiki/Earthhttp://en.wikipedia.org/wiki/Earthhttp://en.wikipedia.org/wiki/Sunhttp://en.wikipedia.org/wiki/Sunhttp://en.wikipedia.org/wiki/Sunhttp://en.wikipedia.org/wiki/Equatorhttp://en.wikipedia.org/wiki/Equatorhttp://en.wikipedia.org/wiki/Equatorhttp://en.wikipedia.org/wiki/Celestial_spherehttp://en.wikipedia.org/wiki/Celestial_spherehttp://en.wikipedia.org/wiki/Celestial_spherehttp://en.wikipedia.org/wiki/Celestial_equatorhttp://en.wikipedia.org/wiki/Celestial_equatorhttp://en.wikipedia.org/wiki/Celestial_equatorhttp://en.wikipedia.org/wiki/Celestial_equatorhttp://en.wikipedia.org/wiki/Subsolar_pointhttp://en.wikipedia.org/wiki/Subsolar_pointhttp://en.wikipedia.org/wiki/Subsolar_pointhttp://en.wikipedia.org/wiki/Equinox#cite_note-1http://en.wikipedia.org/wiki/Equinox#cite_note-1http://en.wikipedia.org/wiki/Equinox#cite_note-1http://en.wikipedia.org/wiki/Julius_Caesarhttp://en.wikipedia.org/wiki/Julius_Caesarhttp://en.wikipedia.org/wiki/Julius_Caesarhttp://en.wikipedia.org/wiki/Julian_calendarhttp://en.wikipedia.org/wiki/Julian_calendarhttp://en.wikipedia.org/wiki/Julian_calendarhttp://en.wikipedia.org/wiki/March_21http://en.wikipedia.org/wiki/March_21http://en.wikipedia.org/wiki/March_21http://en.wikipedia.org/wiki/Pope_Gregory_XIIIhttp://en.wikipedia.org/wiki/Pope_Gregory_XIIIhttp://en.wikipedia.org/wiki/Pope_Gregory_XIIIhttp://en.wikipedia.org/wiki/Gregorian_calendarhttp://en.wikipedia.org/wiki/Gregorian_calendarhttp://en.wikipedia.org/wiki/Gregorian_calendarhttp://en.wikipedia.org/wiki/Roman_emperorhttp://en.wikipedia.org/wiki/Roman_emperorhttp://en.wikipedia.org/wiki/Roman_emperorhttp://en.wikipedia.org/wiki/Roman_emperorhttp://en.wikipedia.org/wiki/Date_of_Easterhttp://en.wikipedia.org/wiki/Date_of_Easterhttp://en.wikipedia.org/wiki/Date_of_Easterhttp://en.wikipedia.org/wiki/First_Council_of_Nicaeahttp://en.wikipedia.org/wiki/First_Council_of_Nicaeahttp://en.wikipedia.org/wiki/First_Council_of_Nicaeahttp://en.wikipedia.org/wiki/Easterhttp://en.wikipedia.org/wiki/Easterhttp://en.wikipedia.org/wiki/Easterhttp://en.wikipedia.org/wiki/Bedehttp://en.wikipedia.org/wiki/Bedehttp://en.wikipedia.org/wiki/Bedehttp://en.wikipedia.org/wiki/Leap_yearhttp://en.wikipedia.org/wiki/Leap_yearhttp://en.wikipedia.org/wiki/Leap_yearhttp://en.wikipedia.org/wiki/Assassinationhttp://en.wikipedia.org/wiki/Assassinationhttp://en.wikipedia.org/wiki/Assassinationhttp://en.wikipedia.org/wiki/Augustushttp://en.wikipedia.org/wiki/Augustushttp://en.wikipedia.org/wiki/Augustushttp://en.wikipedia.org/w/index.php?title=Equinox&action=edit&section=2http://en.wikipedia.org/w/index.php?title=Equinox&action=edit&section=2http://en.wikipedia.org/w/index.php?title=Equinox&action=edit&section=2http://en.wikipedia.org/w/index.php?title=Equinox&action=edit&section=2http://en.wikipedia.org/wiki/Augustushttp://en.wikipedia.org/wiki/Assassinationhttp://en.wikipedia.org/wiki/Leap_yearhttp://en.wikipedia.org/wiki/Bedehttp://en.wikipedia.org/wiki/Easterhttp://en.wikipedia.org/wiki/First_Council_of_Nicaeahttp://en.wikipedia.org/wiki/Date_of_Easterhttp://en.wikipedia.org/wiki/Roman_emperorhttp://en.wikipedia.org/wiki/Roman_emperorhttp://en.wikipedia.org/wiki/Gregorian_calendarhttp://en.wikipedia.org/wiki/Pope_Gregory_XIIIhttp://en.wikipedia.org/wiki/March_21http://en.wikipedia.org/wiki/Julian_calendarhttp://en.wikipedia.org/wiki/Julius_Caesarhttp://en.wikipedia.org/wiki/Equinox#cite_note-1http://en.wikipedia.org/wiki/Equinox#cite_note-1http://en.wikipedia.org/wiki/Subsolar_pointhttp://en.wikipedia.org/wiki/Celestial_equatorhttp://en.wikipedia.org/wiki/Celestial_equatorhttp://en.wikipedia.org/wiki/Celestial_spherehttp://en.wikipedia.org/wiki/Equatorhttp://en.wikipedia.org/wiki/Sunhttp://en.wikipedia.org/wiki/Earthhttp://en.wikipedia.org/wiki/Axial_tilt


6/23

March equinox and September equinox: a usage becoming the preferred standard by technical

writers choosing to avoidNorthern Hemispherebias (implied by assuming that March is in the

springtime and September is autumnaltrue for those in the Northern Hemisphere but exactly

opposite in theSouthern Hemisphere).

Northward equinox and southward equinox: names referring to the apparent motion of the Sun

at the times of the equinox.

Vernal point and autumnal point are the points on the celestial sphere where the Sun is located

on the vernal equinoxand autumnal equinoxrespectively (again, the seasonal attribution is that

of the Northern Hemisphere).

First point (or cusp) ofAriesand first point ofLibraare names used by navigators

andastrologers.Navigational ephemeris tablesrecord the geographic position of the First Point

of Aries as the reference for position of navigational stars. Due to theprecession of the

equinoxes, theastrological signsof the tropical zodiac where these equinoxes are located no

longer correspond with the actualconstellationsonce ascribed to them. The equinoxes are

currently in the constellations ofPiscesandVirgo. Insidereal astrology(notablyHindu astrology),

by contrast, the first point of Aries remains aligned withRas Hammel"the head of the ram", i.e.theAries constellation.

[edit]Length of equinoctial day and night

On a day of the equinox, the center of the Sun spends a roughly equal amount of time above and

below the horizon at every location on the Earth, night and day being of roughly the same length. The

word equinoxderives from the Latin words aequus(equal) and nox(night); in reality, the day is longer

than the night at an equinox. Commonly, thedayis defined as the period when sunlight reaches the

ground in the absence of local obstacles. From the Earth, the Sun appears as a disc rather than a

single point of light, so when the center of the Sun is below the horizon, its upper edge is visible.

Furthermore, the atmosphere refracts light, so even when the upper limb of the Sun is below the

horizon, its rays reach over the horizon to the ground. Insunrise/sunsettables, the assumed

semidiameter (apparentradius) of the Sun is 16minutes of arcand theatmospheric refractionis

assumed to be 34 minutes of arc. Their combination means that when the upper limb of Sun is on the

visible horizon, its center is 50 minutes of arc below the geometric horizon, which is the intersection

with the celestial sphere of a horizontal plane through the eye of the observer. These cumulative

effects make the day about 14 minutes longer than the night at the Equator and longer still towards

the Poles. The real equality of day and night only happens in places far enough from the Equator to

have a seasonal difference in day length of at least 7 minutes, actually occurring a few days towards

the winter side of each equinox.

The date at which sunset and sunrise becomes exactly 12 hours apart is known as the equilux.

Because sunset and sunrise times vary with an observer's geographic location (longitude and

latitude), the equilux likewise depends on location and does not exist for locations sufficiently close to

the Equator. The equinox, however, is a precise moment in time which is common to all observers on

Earth.
http://en.wikipedia.org/wiki/Northern_Hemispherehttp://en.wikipedia.org/wiki/Northern_Hemispherehttp://en.wikipedia.org/wiki/Northern_Hemispherehttp://en.wikipedia.org/wiki/Southern_Hemispherehttp://en.wikipedia.org/wiki/Southern_Hemispherehttp://en.wikipedia.org/wiki/Southern_Hemispherehttp://en.wikipedia.org/wiki/Aries_(astrology)http://en.wikipedia.org/wiki/Aries_(astrology)http://en.wikipedia.org/wiki/Aries_(astrology)http://en.wikipedia.org/wiki/Libra_(astrology)http://en.wikipedia.org/wiki/Libra_(astrology)http://en.wikipedia.org/wiki/Libra_(astrology)http://en.wikipedia.org/wiki/Astrologerhttp://en.wikipedia.org/wiki/Astrologerhttp://en.wikipedia.org/wiki/Astrologerhttp://en.wikipedia.org/wiki/Nautical_almanachttp://en.wikipedia.org/wiki/Nautical_almanachttp://en.wikipedia.org/wiki/Nautical_almanachttp://en.wikipedia.org/wiki/Precession_(astronomy)http://en.wikipedia.org/wiki/Precession_(astronomy)http://en.wikipedia.org/wiki/Precession_(astronomy)http://en.wikipedia.org/wiki/Precession_(astronomy)http://en.wikipedia.org/wiki/Astrological_signshttp://en.wikipedia.org/wiki/Astrological_signshttp://en.wikipedia.org/wiki/Astrological_signshttp://en.wikipedia.org/wiki/Constellationhttp://en.wikipedia.org/wiki/Constellationhttp://en.wikipedia.org/wiki/Constellationhttp://en.wikipedia.org/wiki/Pisces_(constellation)http://en.wikipedia.org/wiki/Pisces_(constellation)http://en.wikipedia.org/wiki/Pisces_(constellation)http://en.wikipedia.org/wiki/Virgo_(constellation)http://en.wikipedia.org/wiki/Virgo_(constellation)http://en.wikipedia.org/wiki/Virgo_(constellation)http://en.wikipedia.org/wiki/Sidereal_astrologyhttp://en.wikipedia.org/wiki/Sidereal_astrologyhttp://en.wikipedia.org/wiki/Sidereal_astrologyhttp://en.wikipedia.org/wiki/Hindu_astrologyhttp://en.wikipedia.org/wiki/Hindu_astrologyhttp://en.wikipedia.org/wiki/Hindu_astrologyhttp://en.wikipedia.org/wiki/Ras_Hammelhttp://en.wikipedia.org/wiki/Ras_Hammelhttp://en.wikipedia.org/wiki/Ras_Hammelhttp://en.wikipedia.org/wiki/Aries_(constellation)http://en.wikipedia.org/wiki/Aries_(constellation)http://en.wikipedia.org/wiki/Aries_(constellation)http://en.wikipedia.org/w/index.php?title=Equinox&action=edit&section=3http://en.wikipedia.org/w/index.php?title=Equinox&action=edit&section=3http://en.wikipedia.org/w/index.php?title=Equinox&action=edit&section=3http://en.wikipedia.org/wiki/Dayhttp://en.wikipedia.org/wiki/Dayhttp://en.wikipedia.org/wiki/Dayhttp://en.wikipedia.org/wiki/Sunrisehttp://en.wikipedia.org/wiki/Sunrisehttp://en.wikipedia.org/wiki/Sunsethttp://en.wikipedia.org/wiki/Sunsethttp://en.wikipedia.org/wiki/Sunsethttp://en.wikipedia.org/wiki/Radiushttp://en.wikipedia.org/wiki/Radiushttp://en.wikipedia.org/wiki/Radiushttp://en.wikipedia.org/wiki/Minute_of_archttp://en.wikipedia.org/wiki/Minute_of_archttp://en.wikipedia.org/wiki/Minute_of_archttp://en.wikipedia.org/wiki/Atmospheric_refractionhttp://en.wikipedia.org/wiki/Atmospheric_refractionhttp://en.wikipedia.org/wiki/Atmospheric_refractionhttp://en.wikipedia.org/wiki/Atmospheric_refractionhttp://en.wikipedia.org/wiki/Minute_of_archttp://en.wikipedia.org/wiki/Radiushttp://en.wikipedia.org/wiki/Sunsethttp://en.wikipedia.org/wiki/Sunrisehttp://en.wikipedia.org/wiki/Dayhttp://en.wikipedia.org/w/index.php?title=Equinox&action=edit&section=3http://en.wikipedia.org/wiki/Aries_(constellation)http://en.wikipedia.org/wiki/Ras_Hammelhttp://en.wikipedia.org/wiki/Hindu_astrologyhttp://en.wikipedia.org/wiki/Sidereal_astrologyhttp://en.wikipedia.org/wiki/Virgo_(constellation)http://en.wikipedia.org/wiki/Pisces_(constellation)http://en.wikipedia.org/wiki/Constellationhttp://en.wikipedia.org/wiki/Astrological_signshttp://en.wikipedia.org/wiki/Precession_(astronomy)http://en.wikipedia.org/wiki/Precession_(astronomy)http://en.wikipedia.org/wiki/Nautical_almanachttp://en.wikipedia.org/wiki/Astrologerhttp://en.wikipedia.org/wiki/Libra_(astrology)http://en.wikipedia.org/wiki/Aries_(astrology)http://en.wikipedia.org/wiki/Southern_Hemispherehttp://en.wikipedia.org/wiki/Northern_Hemisphere


7/23

[edit]Geocentric view of the astronomical seasons

In the half year centered on the June solstice, the Sun rises and sets towards the north, which means

longer days with shorter nights for the Northern Hemisphere and shorter days with longer nights for

the Southern Hemisphere. In the half year centered on the December solstice, the Sun rises and sets

towards the south and the durations of day and night are reversed.

Also on the day of an equinox, the Sun rises everywhere on Earth (except the Poles) at 06:00 in the

morning and sets at 18:00 in the evening (local time). These times are not exact for several reasons,

one being that the Sun is much larger in diameter than the Earth, so that more than half of the Earth

could be in sunlight at any one time (due to unparallel rays creating tangent points beyond an equal-

day-night line); other reasons are as follows:

Most places on Earth use atime zonewhich is unequal to the local time, differing by up to an

hour or even two hours, ifdaylight saving time(summer time) is included. In that case, the Sun

could rise at 08:00 and set at 20:00, but there would still be 12 hours of daylight.

Even those people fortunate enough to have their time zone equal to the local time will not see

sunrise and sunset at 06:00 and 18:00 respectively. This is due to the variable speed of the Earth

in its orbit, and is described as theequation of time. It has different values for the March and

September equinoxes (+8 and 8 minutes respectively).

Sunrise and sunset are commonly defined for the upper limb of the solar disk, rather than its

center. The upper limb is already up for at least one minute before the center appears, and

likewise, the upper limb sets one minute later than the center of the solar disk. Due

toatmospheric refraction, the Sun, when near the horizon, appears a little more than its own

diameter above the position than where it is in reality. This makes sunrise more than another two

minutes earlier and sunset the equal amount later. These two effects add up to almost seven

minutes, making the equinox day 12 h 7 min long and the night only 11 h 53 min. In addition to

that, the night includes twilight. When dawn and dusk are added to the daytime instead, the day

would be almost 13 hours.

The above numbers are only true for thetropics. Formoderate latitudes, this discrepancy

increases (for example, 12 minutes in London) and closer to the Poles it gets very large. Up to

about 100 km from either Pole, the Sun is up for a full 24 hours on an equinox day.

Height of the horizon on both the sunrise and sunset sides changes the day's length. Going up

into the mountains will lengthen the day, while standing in a valley with hilltops on the east and

the west can shorten the day significantly.

[edit]Day arcs of the SunSome of the statements above can be made clearer when picturing the day arc (i.e. the path the Sun

tracks along the celestial dome in itsdiurnalmovement). The pictures show this for every hour on

equinox day. In addition, some 'ghost' suns are also indicated below the horizon, up to 18 down. The

Sun in this area still causestwilight. The pictures can be used for both Northern and Southern

hemispheres. The observer is supposed to sit near the tree on the island in the middle of the ocean;

the green arrows give cardinal directions.

On the northern hemisphere, north is to the left, the Sun rises in the east (far

arrow),culminatesin the south (right arrow) while moving to the right and setting in the west (near

arrow).
http://en.wikipedia.org/w/index.php?title=Equinox&action=edit&section=4http://en.wikipedia.org/w/index.php?title=Equinox&action=edit&section=4http://en.wikipedia.org/w/index.php?title=Equinox&action=edit&section=4http://en.wikipedia.org/wiki/Time_zonehttp://en.wikipedia.org/wiki/Time_zonehttp://en.wikipedia.org/wiki/Time_zonehttp://en.wikipedia.org/wiki/Daylight_saving_timehttp://en.wikipedia.org/wiki/Daylight_saving_timehttp://en.wikipedia.org/wiki/Daylight_saving_timehttp://en.wikipedia.org/wiki/Equation_of_timehttp://en.wikipedia.org/wiki/Equation_of_timehttp://en.wikipedia.org/wiki/Equation_of_timehttp://en.wikipedia.org/wiki/Atmospheric_refractionhttp://en.wikipedia.org/wiki/Atmospheric_refractionhttp://en.wikipedia.org/wiki/Atmospheric_refractionhttp://en.wikipedia.org/wiki/Tropicshttp://en.wikipedia.org/wiki/Tropicshttp://en.wikipedia.org/wiki/Tropicshttp://en.wikipedia.org/wiki/Middle_Latitudeshttp://en.wikipedia.org/wiki/Middle_Latitudeshttp://en.wikipedia.org/wiki/Middle_Latitudeshttp://en.wikipedia.org/w/index.php?title=Equinox&action=edit&section=5http://en.wikipedia.org/w/index.php?title=Equinox&action=edit&section=5http://en.wikipedia.org/w/index.php?title=Equinox&action=edit&section=5http://en.wikipedia.org/wiki/Diurnal_motionhttp://en.wikipedia.org/wiki/Diurnal_motionhttp://en.wikipedia.org/wiki/Diurnal_motionhttp://en.wikipedia.org/wiki/Twilighthttp://en.wikipedia.org/wiki/Twilighthttp://en.wikipedia.org/wiki/Twilighthttp://en.wikipedia.org/wiki/Culminationhttp://en.wikipedia.org/wiki/Culminationhttp://en.wikipedia.org/wiki/Culminationhttp://en.wikipedia.org/wiki/Culminationhttp://en.wikipedia.org/wiki/Twilighthttp://en.wikipedia.org/wiki/Diurnal_motionhttp://en.wikipedia.org/w/index.php?title=Equinox&action=edit&section=5http://en.wikipedia.org/wiki/Middle_Latitudeshttp://en.wikipedia.org/wiki/Tropicshttp://en.wikipedia.org/wiki/Atmospheric_refractionhttp://en.wikipedia.org/wiki/Equation_of_timehttp://en.wikipedia.org/wiki/Daylight_saving_timehttp://en.wikipedia.org/wiki/Time_zonehttp://en.wikipedia.org/w/index.php?title=Equinox&action=edit&section=4


8/23

On the southern hemisphere, south is to the left, the Sun rises in the east (near arrow),

culminates in the north (right arrow) while moving to the left and setting in the west (far arrow).

The following special cases are depicted:

Day arc at 0latitude (Equator)

The arc passes through thezenith, resulting in almost no shadows at high noon.

Day arc at 20latitude

The Sun culminates at 70altitude and its path at sunrise and sunset occurs at a steep 70angle to the horizon.

Twilight still lasts about one hour.
http://en.wikipedia.org/wiki/Zenithhttp://en.wikipedia.org/wiki/Zenithhttp://en.wikipedia.org/wiki/Zenithhttp://en.wikipedia.org/wiki/File:Equinox-50.jpghttp://en.wikipedia.org/wiki/File:Equinox-20.jpghttp://en.wikipedia.org/wiki/File:Equinox-0.jpghttp://en.wikipedia.org/wiki/File:Equinox-50.jpghttp://en.wikipedia.org/wiki/File:Equinox-20.jpghttp://en.wikipedia.org/wiki/File:Equinox-0.jpghttp://en.wikipedia.org/wiki/File:Equinox-50.jpghttp://en.wikipedia.org/wiki/File:Equinox-20.jpghttp://en.wikipedia.org/wiki/File:Equinox-0.jpghttp://en.wikipedia.org/wiki/Zenith


9/23


Twilight lasts almost two hours.


The Sun culminates at no more than 20altitude and its daily path at sunrise and sunset is at a shallow 20

angle to the horizon. Twilight lasts for more than four hours; in fact, there is barely any night.

Day arc at 90latitude (Pole)

If it were not for atmospheric refraction, the Sun would be on the horizon all the time.

[edit]Celestial coordinate systems

The vernal point (vernal equinox) the one the Sun passes in March on its way from south to north

is used as the origin of somecelestial coordinate systems:

in theecliptic coordinate system, the vernal point is the origin of theecliptic longitude;

in theequatorial coordinate system, the vernal point is the origin of theright ascension.

Because of theprecession of the Earth's axis, the position of the vernal point changes with respect to

thecelestial sphereover time and as a consequence, both the equatorial and the ecliptic coordinate

systems change over time. Therefore, when specifying celestial coordinates for an object, one has to

specify at what time the vernal point and the celestial equator are taken. That reference time is called

theequinox of date.[4]
http://en.wikipedia.org/w/index.php?title=Equinox&action=edit&section=6http://en.wikipedia.org/w/index.php?title=Equinox&action=edit&section=6http://en.wikipedia.org/w/index.php?title=Equinox&action=edit&section=6http://en.wikipedia.org/wiki/Celestial_coordinate_systemhttp://en.wikipedia.org/wiki/Celestial_coordinate_systemhttp://en.wikipedia.org/wiki/Celestial_coordinate_systemhttp://en.wikipedia.org/wiki/Ecliptic_coordinate_systemhttp://en.wikipedia.org/wiki/Ecliptic_coordinate_systemhttp://en.wikipedia.org/wiki/Ecliptic_coordinate_systemhttp://en.wikipedia.org/wiki/Ecliptic_longitudehttp://en.wikipedia.org/wiki/Ecliptic_longitudehttp://en.wikipedia.org/wiki/Ecliptic_longitudehttp://en.wikipedia.org/wiki/Equatorial_coordinate_systemhttp://en.wikipedia.org/wiki/Equatorial_coordinate_systemhttp://en.wikipedia.org/wiki/Equatorial_coordinate_systemhttp://en.wikipedia.org/wiki/Right_ascensionhttp://en.wikipedia.org/wiki/Right_ascensionhttp://en.wikipedia.org/wiki/Right_ascensionhttp://en.wikipedia.org/wiki/Precession_(astronomy)http://en.wikipedia.org/wiki/Precession_(astronomy)http://en.wikipedia.org/wiki/Precession_(astronomy)http://en.wikipedia.org/wiki/Celestial_spherehttp://en.wikipedia.org/wiki/Celestial_spherehttp://en.wikipedia.org/wiki/Celestial_spherehttp://en.wikipedia.org/wiki/Equinox_(celestial_coordinates)http://en.wikipedia.org/wiki/Equinox_(celestial_coordinates)http://en.wikipedia.org/wiki/Equinox#cite_note-3http://en.wikipedia.org/wiki/Equinox#cite_note-3http://en.wikipedia.org/wiki/Equinox#cite_note-3http://en.wikipedia.org/wiki/File:Equinox-90.jpghttp://en.wikipedia.org/wiki/File:Equinox-70.jpghttp://en.wikipedia.org/wiki/File:Equinox-90.jpghttp://en.wikipedia.org/wiki/File:Equinox-70.jpghttp://en.wikipedia.org/wiki/Equinox#cite_note-3http://en.wikipedia.org/wiki/Equinox_(celestial_coordinates)http://en.wikipedia.org/wiki/Celestial_spherehttp://en.wikipedia.org/wiki/Precession_(astronomy)http://en.wikipedia.org/wiki/Right_ascensionhttp://en.wikipedia.org/wiki/Equatorial_coordinate_systemhttp://en.wikipedia.org/wiki/Ecliptic_longitudehttp://en.wikipedia.org/wiki/Ecliptic_coordinate_systemhttp://en.wikipedia.org/wiki/Celestial_coordinate_systemhttp://en.wikipedia.org/w/index.php?title=Equinox&action=edit&section=6


10/23

The autumnal equinox is at ecliptic longitude 180 and at right ascension 12h.

Theupper culminationof the vernal point is considered the start of thesidereal dayfor the observer.

Thehour angleof the vernal point is, by definition, the observer'ssidereal time.

Forwestern tropical astrology, the same thing holds true; the vernal equinox is the first point (i.e. the

start) of the sign ofAries. In this system, it is of no significance that the fixed stars and equinox shiftcompared to each other due to theprecession of the equinoxes.

[edit]Cultural aspects

A number of traditionalspringandautumn(harvest) festivals are celebrated on the date of the

equinoxes.

Asia

The traditional East Asian calendars divide a year into 24solar terms(, literally "climatic

segments"), and the vernal equinox (Chnfn,ChineseandJapanese:

;Korean:;Vietnamese:Xun phn) and the autumnal equinox

(Qifn,ChineseandJapanese:;Korean:;Vietnamese:Thu phn) mark the middleof

the spring and autumnseasons, respectively. In this context, theChinese character

means "(equal) division"(within a season).

In Japan, (March) Vernal Equinox Day (Shunbun no hi) is an officialnational holiday,

and is spent visiting family graves and holding family reunions. Similarly, in September, there is

an Autumnal Equinox Day (Shbun no hi).

Neopaganism

Wiccansand many otherNeopaganshold religious celebrations ofOstaraon the spring equinox,

andMabonon the autumnal equinox.

[edit]March equinox commemorations

Bas-reliefinPersepolis- a symbolIranian/PersianNowruz- on the day of an equinox, the power of an eternally fighting

bull (personifying theEarth) and that of a lion (personifying theSun) are equal.
http://en.wikipedia.org/wiki/Equinox#cite_note-3http://en.wikipedia.org/wiki/Equinox#cite_note-3http://en.wikipedia.org/wiki/Culminationhttp://en.wikipedia.org/wiki/Culminationhttp://en.wikipedia.org/wiki/Culminationhttp://en.wikipedia.org/wiki/Sidereal_timehttp://en.wikipedia.org/wiki/Sidereal_timehttp://en.wikipedia.org/wiki/Sidereal_timehttp://en.wikipedia.org/wiki/Hour_anglehttp://en.wikipedia.org/wiki/Hour_anglehttp://en.wikipedia.org/wiki/Hour_anglehttp://en.wikipedia.org/wiki/Sidereal_timehttp://en.wikipedia.org/wiki/Sidereal_timehttp://en.wikipedia.org/wiki/Sidereal_timehttp://en.wikipedia.org/wiki/Western_astrologyhttp://en.wikipedia.org/wiki/Western_astrologyhttp://en.wikipedia.org/wiki/Western_astrologyhttp://en.wikipedia.org/wiki/Aries_(astrology)http://en.wikipedia.org/wiki/Aries_(astrology)http://en.wikipedia.org/wiki/Aries_(astrology)http://en.wikipedia.org/wiki/Precession_(astronomy)http://en.wikipedia.org/wiki/Precession_(astronomy)http://en.wikipedia.org/wiki/Precession_(astronomy)http://en.wikipedia.org/w/index.php?title=Equinox&action=edit&section=7http://en.wikipedia.org/w/index.php?title=Equinox&action=edit&section=7http://en.wikipedia.org/w/index.php?title=Equinox&action=edit&section=7http://en.wikipedia.org/wiki/Spring_(season)http://en.wikipedia.org/wiki/Spring_(season)http://en.wikipedia.org/wiki/Spring_(season)http://en.wikipedia.org/wiki/Autumnhttp://en.wikipedia.org/wiki/Autumnhttp://en.wikipedia.org/wiki/Autumnhttp://en.wikipedia.org/wiki/Harvesthttp://en.wikipedia.org/wiki/Harvesthttp://en.wikipedia.org/wiki/Harvesthttp://en.wikipedia.org/wiki/Solar_termhttp://en.wikipedia.org/wiki/Solar_termhttp://en.wikipedia.org/wiki/Solar_termhttp://en.wikipedia.org/wiki/Chunfenhttp://en.wikipedia.org/wiki/Chunfenhttp://en.wikipedia.org/wiki/Chunfenhttp://en.wikipedia.org/wiki/Chinese_languagehttp://en.wikipedia.org/wiki/Chinese_languagehttp://en.wikipedia.org/wiki/Chinese_languagehttp://en.wikipedia.org/wiki/Japanese_languagehttp://en.wikipedia.org/wiki/Japanese_languagehttp://en.wikipedia.org/wiki/Japanese_languagehttp://en.wikipedia.org/wiki/Korean_languagehttp://en.wikipedia.org/wiki/Korean_languagehttp://en.wikipedia.org/wiki/Korean_languagehttp://en.wikipedia.org/wiki/Vietnamese_languagehttp://en.wikipedia.org/wiki/Vietnamese_languagehttp://en.wikipedia.org/wiki/Vietnamese_languagehttp://en.wikipedia.org/wiki/Qiufenhttp://en.wikipedia.org/wiki/Qiufenhttp://en.wikipedia.org/wiki/Qiufenhttp://en.wikipedia.org/wiki/Chinese_languagehttp://en.wikipedia.org/wiki/Chinese_languagehttp://en.wikipedia.org/wiki/Chinese_languagehttp://en.wikipedia.org/wiki/Japanese_languagehttp://en.wikipedia.org/wiki/Japanese_languagehttp://en.wikipedia.org/wiki/Japanese_languagehttp://en.wikipedia.org/wiki/Korean_languagehttp://en.wikipedia.org/wiki/Korean_languagehttp://en.wikipedia.org/wiki/Korean_languagehttp://en.wikipedia.org/wiki/Vietnamese_languagehttp://en.wikipedia.org/wiki/Vietnamese_languagehttp://en.wikipedia.org/wiki/Vietnamese_languagehttp://en.wikipedia.org/wiki/Seasonhttp://en.wikipedia.org/wiki/Seasonhttp://en.wikipedia.org/wiki/Seasonhttp://en.wikipedia.org/wiki/Chinese_characterhttp://en.wikipedia.org/wiki/Chinese_characterhttp://en.wikipedia.org/wiki/Chinese_characterhttp://en.wikipedia.org/wiki/Holidays_of_Japanhttp://en.wikipedia.org/wiki/Holidays_of_Japanhttp://en.wikipedia.org/wiki/Holidays_of_Japanhttp://en.wikipedia.org/wiki/Wiccahttp://en.wikipedia.org/wiki/Wiccahttp://en.wikipedia.org/wiki/Neopaganismhttp://en.wikipedia.org/wiki/Neopaganismhttp://en.wikipedia.org/wiki/Neopaganismhttp://en.wikipedia.org/wiki/Ostara_(Wicca)http://en.wikipedia.org/wiki/Ostara_(Wicca)http://en.wikipedia.org/wiki/Ostara_(Wicca)http://en.wikipedia.org/wiki/Mabon_(Wicca)http://en.wikipedia.org/wiki/Mabon_(Wicca)http://en.wikipedia.org/wiki/Mabon_(Wicca)http://en.wikipedia.org/w/index.php?title=Equinox&action=edit&section=8http://en.wikipedia.org/w/index.php?title=Equinox&action=edit&section=8http://en.wikipedia.org/w/index.php?title=Equinox&action=edit&section=8http://en.wikipedia.org/wiki/Bas-reliefhttp://en.wikipedia.org/wiki/Bas-reliefhttp://en.wikipedia.org/wiki/Persepolishttp://en.wikipedia.org/wiki/Persepolishttp://en.wikipedia.org/wiki/Persepolishttp://en.wikipedia.org/wiki/Culture_of_Iranhttp://en.wikipedia.org/wiki/Culture_of_Iranhttp://en.wikipedia.org/wiki/Nowruzhttp://en.wikipedia.org/wiki/Nowruzhttp://en.wikipedia.org/wiki/Nowruzhttp://en.wikipedia.org/wiki/Earthhttp://en.wikipedia.org/wiki/Earthhttp://en.wikipedia.org/wiki/Earthhttp://en.wikipedia.org/wiki/Sunhttp://en.wikipedia.org/wiki/Sunhttp://en.wikipedia.org/wiki/Sunhttp://en.wikipedia.org/wiki/File:Nowruz_Zoroastrian.jpghttp://en.wikipedia.org/wiki/File:Nowruz_Zoroastrian.jpghttp://en.wikipedia.org/wiki/File:Nowruz_Zoroastrian.jpghttp://en.wikipedia.org/wiki/File:Nowruz_Zoroastrian.jpghttp://en.wikipedia.org/wiki/Sunhttp://en.wikipedia.org/wiki/Earthhttp://en.wikipedia.org/wiki/Nowruzhttp://en.wikipedia.org/wiki/Culture_of_Iranhttp://en.wikipedia.org/wiki/Persepolishttp://en.wikipedia.org/wiki/Bas-reliefhttp://en.wikipedia.org/w/index.php?title=Equinox&action=edit&section=8http://en.wikipedia.org/wiki/Mabon_(Wicca)http://en.wikipedia.org/wiki/Ostara_(Wicca)http://en.wikipedia.org/wiki/Neopaganismhttp://en.wikipedia.org/wiki/Wiccahttp://en.wikipedia.org/wiki/Holidays_of_Japanhttp://en.wikipedia.org/wiki/Chinese_characterhttp://en.wikipedia.org/wiki/Seasonhttp://en.wikipedia.org/wiki/Vietnamese_languagehttp://en.wikipedia.org/wiki/Korean_languagehttp://en.wikipedia.org/wiki/Japanese_languagehttp://en.wikipedia.org/wiki/Chinese_languagehttp://en.wikipedia.org/wiki/Qiufenhttp://en.wikipedia.org/wiki/Vietnamese_languagehttp://en.wikipedia.org/wiki/Korean_languagehttp://en.wikipedia.org/wiki/Japanese_languagehttp://en.wikipedia.org/wiki/Chinese_languagehttp://en.wikipedia.org/wiki/Chunfenhttp://en.wikipedia.org/wiki/Solar_termhttp://en.wikipedia.org/wiki/Harvesthttp://en.wikipedia.org/wiki/Autumnhttp://en.wikipedia.org/wiki/Spring_(season)http://en.wikipedia.org/w/index.php?title=Equinox&action=edit&section=7http://en.wikipedia.org/wiki/Precession_(astronomy)http://en.wikipedia.org/wiki/Aries_(astrology)http://en.wikipedia.org/wiki/Western_astrologyhttp://en.wikipedia.org/wiki/Sidereal_timehttp://en.wikipedia.org/wiki/Hour_anglehttp://en.wikipedia.org/wiki/Sidereal_timehttp://en.wikipedia.org/wiki/Culmination


11/23

Chichen Itzapyramid during the spring equinox -Kukulkan, the famous descent of the snake

Near East

The March equinox marks the first day of various calendars including theIranian calendar. TheancientIraniannew year's festival ofNowruzcan be celebrated March 20 or March 21. According

to the ancient Persian mythology Jamshid, the mythological king of Persia, ascended to the

throne on this day and each year this is commemorated with festivities for two weeks. These

festivities recall the story of creation and the ancient cosmology of Iranian and Persian people. It

is also a holiday celebrated inAzerbaijan,Afghanistan,Pakistan,Turkey,Zanzibar,Albania, and

various countries ofCentral Asia, as well as among theKurds. As well as being

aZoroastrianholiday, it is also a holy day for adherents of theBah' Faithand theNizari Ismaili

Muslims.[5]

The Bah' Naw-rz is stationary; the new year always starts at sunset March 20.[6]

Sham El Nessimwas anancient Egyptianholiday which can be traced back as far as 2700 BC. It

is still one of thepublic holidays in Egypt. Sometime during Egypt's Christian period (c. 200-639)

the date moved toEaster Monday, but before then it coincided with the vernal equinox.

In manyArabcountries,Mother's Dayis celebrated on the March equinox.

Abrahamic tradition

TheJewishPassoverusually falls on the firstfull moonafter the Northern Hemisphere vernal

equinox, although occasionally (7 times every 19 years) it will occur on the second full moon.[citation

needed]

TheChristian churchescalculateEasteras the first Sunday after the first full moon on or after the

March equinox. The official church definition for the equinox is March 21; however, as theEastern

Orthodox Churchesuse the olderJulian calendar, while the Western Churches use theGregorian

calendar, both of which designate March 21 as the equinox, the actualdate of Easterdiffers. The

earliest possible Easter date in any year is therefore March 22 on each calendar. The latest

possible Easter date in any year is April 25.[7]

South Asia

Tamiland Bengali New Years follow the Hinduzodiacand are celebrated according to the

sidereal vernal equinox (April 14). The former is celebrated in the South Indian state ofTamil

Nadu, and the latter inBangladeshand the East Indian state ofWest Bengal.

Andhra Pradesh,KarnatakaandMaharastrapeople celebrate new yearugadiset

bySatavahanaon the first morning after first new moon from March equinox. Also the

calculations of the great Indian MathematicianBhaskaracharyaproclaim the Ugadi day as thebeginning of the New Year, New month and New day.
http://en.wikipedia.org/wiki/Chichen_Itzahttp://en.wikipedia.org/wiki/Chichen_Itzahttp://en.wikipedia.org/wiki/Kukulkanhttp://en.wikipedia.org/wiki/Kukulkanhttp://en.wikipedia.org/wiki/Kukulkanhttp://en.wikipedia.org/wiki/Iranian_calendarhttp://en.wikipedia.org/wiki/Iranian_calendarhttp://en.wikipedia.org/wiki/Iranian_calendarhttp://en.wikipedia.org/wiki/Iranian_peoplehttp://en.wikipedia.org/wiki/Iranian_peoplehttp://en.wikipedia.org/wiki/Iranian_peoplehttp://en.wikipedia.org/wiki/Nowruzhttp://en.wikipedia.org/wiki/Nowruzhttp://en.wikipedia.org/wiki/Nowruzhttp://en.wikipedia.org/wiki/Azerbaijanhttp://en.wikipedia.org/wiki/Azerbaijanhttp://en.wikipedia.org/wiki/Azerbaijanhttp://en.wikipedia.org/wiki/Afghanistanhttp://en.wikipedia.org/wiki/Afghanistanhttp://en.wikipedia.org/wiki/Afghanistanhttp://en.wikipedia.org/wiki/Pakistanhttp://en.wikipedia.org/wiki/Pakistanhttp://en.wikipedia.org/wiki/Pakistanhttp://en.wikipedia.org/wiki/Turkeyhttp://en.wikipedia.org/wiki/Turkeyhttp://en.wikipedia.org/wiki/Turkeyhttp://en.wikipedia.org/wiki/Zanzibarhttp://en.wikipedia.org/wiki/Zanzibarhttp://en.wikipedia.org/wiki/Zanzibarhttp://en.wikipedia.org/wiki/Albaniahttp://en.wikipedia.org/wiki/Albaniahttp://en.wikipedia.org/wiki/Albaniahttp://en.wikipedia.org/wiki/Central_Asiahttp://en.wikipedia.org/wiki/Central_Asiahttp://en.wikipedia.org/wiki/Central_Asiahttp://en.wikipedia.org/wiki/Kurdish_peoplehttp://en.wikipedia.org/wiki/Kurdish_peoplehttp://en.wikipedia.org/wiki/Kurdish_peoplehttp://en.wikipedia.org/wiki/Zoroastrianismhttp://en.wikipedia.org/wiki/Zoroastrianismhttp://en.wikipedia.org/wiki/Zoroastrianismhttp://en.wikipedia.org/wiki/Bah%C3%A1%27%C3%AD_Faithhttp://en.wikipedia.org/wiki/Bah%C3%A1%27%C3%AD_Faithhttp://en.wikipedia.org/wiki/Bah%C3%A1%27%C3%AD_Faithhttp://en.wikipedia.org/wiki/Ismailihttp://en.wikipedia.org/wiki/Ismailihttp://en.wikipedia.org/wiki/Ismailihttp://en.wikipedia.org/wiki/Equinox#cite_note-4http://en.wikipedia.org/wiki/Equinox#cite_note-4http://en.wikipedia.org/wiki/Equinox#cite_note-4http://en.wikipedia.org/wiki/Equinox#cite_note-5http://en.wikipedia.org/wiki/Equinox#cite_note-5http://en.wikipedia.org/wiki/Equinox#cite_note-5http://en.wikipedia.org/wiki/Sham_El_Nessimhttp://en.wikipedia.org/wiki/Sham_El_Nessimhttp://en.wikipedia.org/wiki/Ancient_Egypthttp://en.wikipedia.org/wiki/Ancient_Egypthttp://en.wikipedia.org/wiki/Ancient_Egypthttp://en.wikipedia.org/wiki/Public_holidays_in_Egypthttp://en.wikipedia.org/wiki/Public_holidays_in_Egypthttp://en.wikipedia.org/wiki/Public_holidays_in_Egypthttp://en.wikipedia.org/wiki/Easter_Mondayhttp://en.wikipedia.org/wiki/Easter_Mondayhttp://en.wikipedia.org/wiki/Easter_Mondayhttp://en.wikipedia.org/wiki/Arabhttp://en.wikipedia.org/wiki/Arabhttp://en.wikipedia.org/wiki/Arabhttp://en.wikipedia.org/wiki/Mother%27s_Dayhttp://en.wikipedia.org/wiki/Mother%27s_Dayhttp://en.wikipedia.org/wiki/Mother%27s_Dayhttp://en.wikipedia.org/wiki/Jewishhttp://en.wikipedia.org/wiki/Jewishhttp://en.wikipedia.org/wiki/Passoverhttp://en.wikipedia.org/wiki/Passoverhttp://en.wikipedia.org/wiki/Passoverhttp://en.wikipedia.org/wiki/Full_moonhttp://en.wikipedia.org/wiki/Full_moonhttp://en.wikipedia.org/wiki/Full_moonhttp://en.wikipedia.org/wiki/Wikipedia:Citation_neededhttp://en.wikipedia.org/wiki/Wikipedia:Citation_neededhttp://en.wikipedia.org/wiki/Wikipedia:Citation_neededhttp://en.wikipedia.org/wiki/Wikipedia:Citation_neededhttp://en.wikipedia.org/wiki/Christian_churchhttp://en.wikipedia.org/wiki/Christian_churchhttp://en.wikipedia.org/wiki/Computushttp://en.wikipedia.org/wiki/Computushttp://en.wikipedia.org/wiki/Easterhttp://en.wikipedia.org/wiki/Easterhttp://en.wikipedia.org/wiki/Easterhttp://en.wikipedia.org/wiki/Eastern_Orthodox_Churcheshttp://en.wikipedia.org/wiki/Eastern_Orthodox_Churcheshttp://en.wikipedia.org/wiki/Eastern_Orthodox_Churcheshttp://en.wikipedia.org/wiki/Eastern_Orthodox_Churcheshttp://en.wikipedia.org/wiki/Julian_calendarhttp://en.wikipedia.org/wiki/Julian_calendarhttp://en.wikipedia.org/wiki/Julian_calendarhttp://en.wikipedia.org/wiki/Gregorian_calendarhttp://en.wikipedia.org/wiki/Gregorian_calendarhttp://en.wikipedia.org/wiki/Gregorian_calendarhttp://en.wikipedia.org/wiki/Gregorian_calendarhttp://en.wikipedia.org/wiki/Date_of_Easterhttp://en.wikipedia.org/wiki/Date_of_Easterhttp://en.wikipedia.org/wiki/Date_of_Easterhttp://en.wikipedia.org/wiki/Equinox#cite_note-6http://en.wikipedia.org/wiki/Equinox#cite_note-6http://en.wikipedia.org/wiki/Equinox#cite_note-6http://en.wikipedia.org/wiki/Tamil_peoplehttp://en.wikipedia.org/wiki/Tamil_peoplehttp://en.wikipedia.org/wiki/Zodiachttp://en.wikipedia.org/wiki/Zodiachttp://en.wikipedia.org/wiki/Zodiachttp://en.wikipedia.org/wiki/Tamil_Naduhttp://en.wikipedia.org/wiki/Tamil_Naduhttp://en.wikipedia.org/wiki/Tamil_Naduhttp://en.wikipedia.org/wiki/Tamil_Naduhttp://en.wikipedia.org/wiki/Bengali_calendarhttp://en.wikipedia.org/wiki/Bengali_calendarhttp://en.wikipedia.org/wiki/Bengali_calendarhttp://en.wikipedia.org/wiki/West_Bengalhttp://en.wikipedia.org/wiki/West_Bengalhttp://en.wikipedia.org/wiki/West_Bengalhttp://en.wikipedia.org/wiki/Andhra_Pradeshhttp://en.wikipedia.org/wiki/Andhra_Pradeshhttp://en.wikipedia.org/wiki/Karnatakahttp://en.wikipedia.org/wiki/Karnatakahttp://en.wikipedia.org/wiki/Karnatakahttp://en.wikipedia.org/wiki/Maharastrahttp://en.wikipedia.org/wiki/Maharastrahttp://en.wikipedia.org/wiki/Maharastrahttp://en.wikipedia.org/wiki/Ugadihttp://en.wikipedia.org/wiki/Ugadihttp://en.wikipedia.org/wiki/Ugadihttp://en.wikipedia.org/wiki/Satavahanahttp://en.wikipedia.org/wiki/Satavahanahttp://en.wikipedia.org/wiki/Satavahanahttp://en.wikipedia.org/wiki/Bhaskaracharyahttp://en.wikipedia.org/wiki/Bhaskaracharyahttp://en.wikipedia.org/wiki/Bhaskaracharyahttp://en.wikipedia.org/wiki/File:ChichenItzaEquinox.jpghttp://en.wikipedia.org/wiki/File:ChichenItzaEquinox.jpghttp://en.wikipedia.org/wiki/File:ChichenItzaEquinox.jpghttp://en.wikipedia.org/wiki/File:ChichenItzaEquinox.jpghttp://en.wikipedia.org/wiki/Bhaskaracharyahttp://en.wikipedia.org/wiki/Satavahanahttp://en.wikipedia.org/wiki/Ugadihttp://en.wikipedia.org/wiki/Maharastrahttp://en.wikipedia.org/wiki/Karnatakahttp://en.wikipedia.org/wiki/Andhra_Pradeshhttp://en.wikipedia.org/wiki/West_Bengalhttp://en.wikipedia.org/wiki/Bengali_calendarhttp://en.wikipedia.org/wiki/Tamil_Naduhttp://en.wikipedia.org/wiki/Tamil_Naduhttp://en.wikipedia.org/wiki/Zodiachttp://en.wikipedia.org/wiki/Tamil_peoplehttp://en.wikipedia.org/wiki/Equinox#cite_note-6http://en.wikipedia.org/wiki/Date_of_Easterhttp://en.wikipedia.org/wiki/Gregorian_calendarhttp://en.wikipedia.org/wiki/Gregorian_calendarhttp://en.wikipedia.org/wiki/Julian_calendarhttp://en.wikipedia.org/wiki/Eastern_Orthodox_Churcheshttp://en.wikipedia.org/wiki/Eastern_Orthodox_Churcheshttp://en.wikipedia.org/wiki/Easterhttp://en.wikipedia.org/wiki/Computushttp://en.wikipedia.org/wiki/Christian_churchhttp://en.wikipedia.org/wiki/Wikipedia:Citation_neededhttp://en.wikipedia.org/wiki/Wikipedia:Citation_neededhttp://en.wikipedia.org/wiki/Full_moonhttp://en.wikipedia.org/wiki/Passoverhttp://en.wikipedia.org/wiki/Jewishhttp://en.wikipedia.org/wiki/Mother%27s_Dayhttp://en.wikipedia.org/wiki/Arabhttp://en.wikipedia.org/wiki/Easter_Mondayhttp://en.wikipedia.org/wiki/Public_holidays_in_Egypthttp://en.wikipedia.org/wiki/Ancient_Egypthttp://en.wikipedia.org/wiki/Sham_El_Nessimhttp://en.wikipedia.org/wiki/Equinox#cite_note-5http://en.wikipedia.org/wiki/Equinox#cite_note-4http://en.wikipedia.org/wiki/Ismailihttp://en.wikipedia.org/wiki/Ismailihttp://en.wikipedia.org/wiki/Bah%C3%A1%27%C3%AD_Faithhttp://en.wikipedia.org/wiki/Zoroastrianismhttp://en.wikipedia.org/wiki/Kurdish_peoplehttp://en.wikipedia.org/wiki/Central_Asiahttp://en.wikipedia.org/wiki/Albaniahttp://en.wikipedia.org/wiki/Zanzibarhttp://en.wikipedia.org/wiki/Turkeyhttp://en.wikipedia.org/wiki/Pakistanhttp://en.wikipedia.org/wiki/Afghanistanhttp://en.wikipedia.org/wiki/Azerbaijanhttp://en.wikipedia.org/wiki/Nowruzhttp://en.wikipedia.org/wiki/Iranian_peoplehttp://en.wikipedia.org/wiki/Iranian_calendarhttp://en.wikipedia.org/wiki/Kukulkanhttp://en.wikipedia.org/wiki/Chichen_Itza


12/23

In theIndian statesOrissa, the celestial vernal equinox is celebrated as thenew yeararound April

14. It is known as 'Vishuva Sankranti' (meaning "equal" inSanskrit). InKeralathough the new

year is on Chingam 1, the beginning of Zodiac Leo, celestial vernal equinox is celebrated much

more than new year as 'Vishu'

Europe

inNorse paganism, aDsabltwas celebrated on vernal equinox.[8]

Far East

JapanShunbun no hi

Modern culture

World Storytelling Dayis a global celebration of the art of oral storytelling, celebrated every year

on the spring equinox in the northern hemisphere, the first day of autumn equinox in the southern.

World CitizenDay occurs on the March equinox.[9]

InAnnapolis, Marylandin theUnited States, boatyard employees and sailboat owners celebrate

the spring equinox with the Burning Of The Socks festival. Traditionally, the boating community

wears socks only during the winter. These are burned at the approach of warmer weather, which

brings more customers and work to the area. Officially, nobody then wears socks until the next

equinox.[10][11]

[edit]September equinox commemorations

Near East

The September equinox marks the first day of Mehr or Libra in theIranian calendar. It is one of

theIranian festivalscalled JashneMihragan, or the festival of sharing or love inZoroastrianism.

East Asia

In Korea,Chuseokis a major harvest festival and a three-day holiday celebrated around the

Autumn Equinox.

TheMid-Autumn Festivalis celebrated on the 15th day of the 8thlunar month, often near the

autumnal equinox day, and is an official holiday in mainland China, Hong Kong, Taiwan and in

many countries with a significant Chinese minority. As the lunar calendar is not synchronous with

the Gregorian calendar, this date could be anywhere from mid-September to early October.

Europe

The traditionalharvest festivalin the United Kingdom was celebrated on the Sunday of the fullmoon closest to the September equinox.

The September equinox was "New Year's Day" in theFrench Republican Calendar, which was in

use from 1793 to 1805. TheFrench First Republicwas proclaimed and theFrench monarchywas

abolished on September 21, 1792, making the following day (the equinox day that year) the first

day of the "Republican Era" in France. The start of every year was to be determined by

astronomical calculations following the real Sun and not the mean Sun.

[edit]Equinoxes of other planets
http://en.wikipedia.org/wiki/States_and_territories_of_Indiahttp://en.wikipedia.org/wiki/States_and_territories_of_Indiahttp://en.wikipedia.org/wiki/Orissahttp://en.wikipedia.org/wiki/Orissahttp://en.wikipedia.org/wiki/Orissahttp://en.wikipedia.org/wiki/New_yearhttp://en.wikipedia.org/wiki/New_yearhttp://en.wikipedia.org/wiki/New_yearhttp://en.wikipedia.org/wiki/Vishuva_Sankrantihttp://en.wikipedia.org/wiki/Vishuva_Sankrantihttp://en.wikipedia.org/wiki/Vishuva_Sankrantihttp://en.wikipedia.org/wiki/Sanskrithttp://en.wikipedia.org/wiki/Sanskrithttp://en.wikipedia.org/wiki/Sanskrithttp://en.wikipedia.org/wiki/Keralahttp://en.wikipedia.org/wiki/Keralahttp://en.wikipedia.org/wiki/Keralahttp://en.wikipedia.org/wiki/Vishuhttp://en.wikipedia.org/wiki/Vishuhttp://en.wikipedia.org/wiki/Vishuhttp://en.wikipedia.org/wiki/Norse_paganismhttp://en.wikipedia.org/wiki/Norse_paganismhttp://en.wikipedia.org/wiki/Norse_paganismhttp://en.wikipedia.org/wiki/D%C3%ADsabl%C3%B3thttp://en.wikipedia.org/wiki/D%C3%ADsabl%C3%B3thttp://en.wikipedia.org/wiki/D%C3%ADsabl%C3%B3thttp://en.wikipedia.org/wiki/Equinox#cite_note-7http://en.wikipedia.org/wiki/Equinox#cite_note-7http://en.wikipedia.org/wiki/Equinox#cite_note-7http://en.wikipedia.org/wiki/Vernal_Equinox_Dayhttp://en.wikipedia.org/wiki/Vernal_Equinox_Dayhttp://en.wikipedia.org/wiki/Vernal_Equinox_Dayhttp://en.wikipedia.org/wiki/World_Storytelling_Dayhttp://en.wikipedia.org/wiki/World_Storytelling_Dayhttp://en.wikipedia.org/wiki/World_Citizenhttp://en.wikipedia.org/wiki/World_Citizenhttp://en.wikipedia.org/wiki/Equinox#cite_note-8http://en.wikipedia.org/wiki/Equinox#cite_note-8http://en.wikipedia.org/wiki/Equinox#cite_note-8http://en.wikipedia.org/wiki/Annapolis,_Marylandhttp://en.wikipedia.org/wiki/Annapolis,_Marylandhttp://en.wikipedia.org/wiki/Annapolis,_Marylandhttp://en.wikipedia.org/wiki/United_Stateshttp://en.wikipedia.org/wiki/United_Stateshttp://en.wikipedia.org/wiki/United_Stateshttp://en.wikipedia.org/wiki/Equinox#cite_note-9http://en.wikipedia.org/wiki/Equinox#cite_note-9http://en.wikipedia.org/wiki/Equinox#cite_note-9http://en.wikipedia.org/w/index.php?title=Equinox&action=edit&section=9http://en.wikipedia.org/w/index.php?title=Equinox&action=edit&section=9http://en.wikipedia.org/w/index.php?title=Equinox&action=edit&section=9http://en.wikipedia.org/wiki/Iranian_calendarhttp://en.wikipedia.org/wiki/Iranian_calendarhttp://en.wikipedia.org/wiki/Iranian_calendarhttp://en.wikipedia.org/wiki/Iranian_festivalshttp://en.wikipedia.org/wiki/Iranian_festivalshttp://en.wikipedia.org/wiki/Iranian_festivalshttp://en.wikipedia.org/wiki/Mehreganhttp://en.wikipedia.org/wiki/Mehreganhttp://en.wikipedia.org/wiki/Mehreganhttp://en.wikipedia.org/wiki/Zoroastrianismhttp://en.wikipedia.org/wiki/Zoroastrianismhttp://en.wikipedia.org/wiki/Zoroastrianismhttp://en.wikipedia.org/wiki/Chuseokhttp://en.wikipedia.org/wiki/Chuseokhttp://en.wikipedia.org/wiki/Chuseokhttp://en.wikipedia.org/wiki/Mid-Autumn_Festivalhttp://en.wikipedia.org/wiki/Mid-Autumn_Festivalhttp://en.wikipedia.org/wiki/Mid-Autumn_Festivalhttp://en.wikipedia.org/wiki/Lunar_monthhttp://en.wikipedia.org/wiki/Lunar_monthhttp://en.wikipedia.org/wiki/Lunar_monthhttp://en.wikipedia.org/wiki/Harvest_festivalhttp://en.wikipedia.org/wiki/Harvest_festivalhttp://en.wikipedia.org/wiki/Harvest_festivalhttp://en.wikipedia.org/wiki/New_Year%27s_Dayhttp://en.wikipedia.org/wiki/New_Year%27s_Dayhttp://en.wikipedia.org/wiki/New_Year%27s_Dayhttp://en.wikipedia.org/wiki/French_Republican_Calendarhttp://en.wikipedia.org/wiki/French_Republican_Calendarhttp://en.wikipedia.org/wiki/French_Republican_Calendarhttp://en.wikipedia.org/wiki/French_First_Republichttp://en.wikipedia.org/wiki/French_First_Republichttp://en.wikipedia.org/wiki/French_First_Republichttp://en.wikipedia.org/wiki/List_of_French_monarchshttp://en.wikipedia.org/wiki/List_of_French_monarchshttp://en.wikipedia.org/wiki/List_of_French_monarchshttp://en.wikipedia.org/w/index.php?title=Equinox&action=edit&section=10http://en.wikipedia.org/w/index.php?title=Equinox&action=edit&section=10http://en.wikipedia.org/w/index.php?title=Equinox&action=edit&section=10http://en.wikipedia.org/w/index.php?title=Equinox&action=edit&section=10http://en.wikipedia.org/wiki/List_of_French_monarchshttp://en.wikipedia.org/wiki/French_First_Republichttp://en.wikipedia.org/wiki/French_Republican_Calendarhttp://en.wikipedia.org/wiki/New_Year%27s_Dayhttp://en.wikipedia.org/wiki/Harvest_festivalhttp://en.wikipedia.org/wiki/Lunar_monthhttp://en.wikipedia.org/wiki/Mid-Autumn_Festivalhttp://en.wikipedia.org/wiki/Chuseokhttp://en.wikipedia.org/wiki/Zoroastrianismhttp://en.wikipedia.org/wiki/Mehreganhttp://en.wikipedia.org/wiki/Iranian_festivalshttp://en.wikipedia.org/wiki/Iranian_calendarhttp://en.wikipedia.org/w/index.php?title=Equinox&action=edit&section=9http://en.wikipedia.org/wiki/Equinox#cite_note-9http://en.wikipedia.org/wiki/Equinox#cite_note-9http://en.wikipedia.org/wiki/United_Stateshttp://en.wikipedia.org/wiki/Annapolis,_Marylandhttp://en.wikipedia.org/wiki/Equinox#cite_note-8http://en.wikipedia.org/wiki/World_Citizenhttp://en.wikipedia.org/wiki/World_Storytelling_Dayhttp://en.wikipedia.org/wiki/Vernal_Equinox_Dayhttp://en.wikipedia.org/wiki/Equinox#cite_note-7http://en.wikipedia.org/wiki/D%C3%ADsabl%C3%B3thttp://en.wikipedia.org/wiki/Norse_paganismhttp://en.wikipedia.org/wiki/Vishuhttp://en.wikipedia.org/wiki/Keralahttp://en.wikipedia.org/wiki/Sanskrithttp://en.wikipedia.org/wiki/Vishuva_Sankrantihttp://en.wikipedia.org/wiki/New_yearhttp://en.wikipedia.org/wiki/Orissahttp://en.wikipedia.org/wiki/States_and_territories_of_India


13/23

When the planetSaturnis at equinox, itsringspick up almost no light, as seen in this image byCassiniin 2009.

Equinox is a phenomenon that can occur on any planet with a significant tilt to its rotational axis. Most

dramatic of these isSaturn, where the equinox places its normally majesticring systemedge-on

facing the Sun. As a result, they are visible only as a thin line when seen from Earth. When seen from

abovea view seen by humans during an equinox for the first time from theCassinispace probe in

2009they receive very littlesunshine, indeed moreplanetshinethan light from the Sun.

This lack of sunshine occurs once every 14 years and 266 days. It can last a few weeks before and

after the exact equinox. The most recent exact equinox for Saturn was on August 11, 2009. Its next

equinox will take place on April 30, 2024.
http://en.wikipedia.org/wiki/Saturnhttp://en.wikipedia.org/wiki/Saturnhttp://en.wikipedia.org/wiki/Saturnhttp://en.wikipedia.org/wiki/Rings_of_Saturnhttp://en.wikipedia.org/wiki/Rings_of_Saturnhttp://en.wikipedia.org/wiki/Rings_of_Saturnhttp://en.wikipedia.org/wiki/Cassini%E2%80%93Huygenshttp://en.wikipedia.org/wiki/Cassini%E2%80%93Huygenshttp://en.wikipedia.org/wiki/Cassini%E2%80%93Huygenshttp://en.wikipedia.org/wiki/Saturnhttp://en.wikipedia.org/wiki/Saturnhttp://en.wikipedia.org/wiki/Saturnhttp://en.wikipedia.org/wiki/Rings_of_Saturnhttp://en.wikipedia.org/wiki/Rings_of_Saturnhttp://en.wikipedia.org/wiki/Rings_of_Saturnhttp://en.wikipedia.org/wiki/Cassini%E2%80%93Huygenshttp://en.wikipedia.org/wiki/Cassini%E2%80%93Huygenshttp://en.wikipedia.org/wiki/Cassini%E2%80%93Huygenshttp://en.wikipedia.org/wiki/Sunshinehttp://en.wikipedia.org/wiki/Sunshinehttp://en.wikipedia.org/wiki/Sunshinehttp://en.wikipedia.org/wiki/Planetshinehttp://en.wikipedia.org/wiki/Planetshinehttp://en.wikipedia.org/wiki/File:Saturn,_its_rings,_and_a_few_of_its_moons.jpghttp://en.wikipedia.org/wiki/File:Saturn,_its_rings,_and_a_few_of_its_moons.jpghttp://en.wikipedia.org/wiki/File:Saturn,_its_rings,_and_a_few_of_its_moons.jpghttp://en.wikipedia.org/wiki/File:Saturn,_its_rings,_and_a_few_of_its_moons.jpghttp://en.wikipedia.org/wiki/Planetshinehttp://en.wikipedia.org/wiki/Sunshinehttp://en.wikipedia.org/wiki/Cassini%E2%80%93Huygenshttp://en.wikipedia.org/wiki/Rings_of_Saturnhttp://en.wikipedia.org/wiki/Saturnhttp://en.wikipedia.org/wiki/Cassini%E2%80%93Huygenshttp://en.wikipedia.org/wiki/Rings_of_Saturnhttp://en.wikipedia.org/wiki/Saturn


14/23

Glossary of Terms

Ascending node: The point of intersection between a planet's orbit and the planeof the Sun's equator, where the planet is moving northward ("upward") across the

plane of the Sun's equator.

Astronomical Units (AU): A measure of distance where one AU is just aboutequal to the average distance of the Earth from the Sun, 1.49597870691 x 108 ( 3)kilometers.

Barycenter: The center of mass for a multi-body system of mutually orbitingbodies. The system orbits about the barycenter.

Celestial sphere: A gigantic imaginary sphere surrounding a stationary Earth upon

which the stars are affixed. It was once believed that the celestial sphere was real.However, it is now regarded solely as a convenient descriptive tool.

Celestial equator: The projection of the Earth's equator onto the celestial sphere.

Copernican: One who subscribes to the Copernican world view of a heliocentricuniverse, i.e., one who believes that the Earth orbits around a fixed Sun.

Declination (DEC): A heavenly object's position in the sky as measured along a

meridian in degrees (0 to 90 degrees) north (+) or south (-) from the equator.

Descending node: The point of intersection between a planet's orbit and the plane

of the Sun's equator, where the planet is moving southward ("downward") across theplane of the Sun's equator.
http://ssd.jpl.nasa.gov/astro_constants.htmlhttp://ssd.jpl.nasa.gov/astro_constants.htmlhttp://ssd.jpl.nasa.gov/astro_constants.htmlhttp://ssd.jpl.nasa.gov/astro_constants.htmlhttp://ssd.jpl.nasa.gov/astro_constants.htmlhttp://ssd.jpl.nasa.gov/astro_constants.htmlhttp://ssd.jpl.nasa.gov/astro_constants.htmlhttp://ssd.jpl.nasa.gov/astro_constants.html


15/23

Eccentric Anomaly: a time dependent term in Kepler's equation which must besolved for in order to calculate a planet's position on its orbit.

Eccentricity: A measure of how "elliptical" an eclipse is (measured from 0 to 1). For

example, a circle has an eccentricity of zero, not very elliptical. A relationship can bestated mathematically between the semi-major axis a, the semi-minor axis b and theeccentricitye where:

Above are four ellipses with varying eccentricities. The first is a circle.

Ecliptic: As seen from the Earth the ecliptic is the Sun's annual path across the sky.

Ephemerides: plural ofephemeris. Tables containing the calculated positions(usually RA and DEC) of celestial objects for different times, usually at regularintervals.

Ellipse: One of the conic sections, those shapes which are the intersection of a coneand plane. The ellipse is a geometric shape that looks like a squashed circle. You caneasily make an ellipse with two thumb tacks and a loop of string. Place the two tacksinto a paper and loop the string around them. Place a pencil in the loop of string andmove it outwards until the loop becomes taut. Move the pencil around the tacksalways keeping the slack out of the loop. The figure drawn is an ellipse. The points

where the thumbtacks lie are the foci of the ellipse (singular focus).


16/23

Elliptical: Shaped like an ellipse.

First point of Aries: The position against the background stars of the Earth'sdescending node as seen from the Sun.

Foci: Plural of focus.See ellipse.

Geocentric: Earth centered.

Geocentric equatorial coordinates: An X,Y,Z coordinate system centered on theEarth in which the Earth's equator lies in the X-Y plane.

Heliocentric: Sun centered.

Heliocentric ecliptic cartesian coordinates: An X,Y,Z coordinate systemcentered on the Sun in which the ecliptic lies in the X-Y plane.

Heliocentric equatorial cartesian coordinates: An X,Y,Z coordinate systemcentered on the Sun in which the Sun's equator lies in the X-Y plane.

Kepler's Equation: An equation derived from Kepler's Laws whose solution canspecify the position of a planet in its orbit for a specified time given a set oforbital

parameters.

Mean anomaly: The angle between the perihelion and the mean planetasmeasured in the plane of its orbit.

Mean planet: An imaginary planet which moves at a constant velocity around acircular orbit with a radius equal to the semi-major axis of the actual planet's orbit.

Numerical method: A method for solving mathematics problems, usually bycomputer, through the repeated use of simple arithmetic operations.
http://www.davidcolarusso.com/astro/#ellipsehttp://www.davidcolarusso.com/astro/#ellipsehttp://www.davidcolarusso.com/astro/#ellipsehttp://www.davidcolarusso.com/astro/#ellipse


17/23

Orbital parameters: A set of physical parameters for the orbit of a planetsufficient to predict the position of the planet at a given time t. The orbitalparameters used in the simulation above can be foundat:http://ssd.jpl.nasa.gov/elem_planets.html(valid as of June 2004).

Perihelion: The closest point on a planet's orbit to the Sun.

Period (of a planet): The length of time it takes a planet to return to the sameplace in its orbit.

PI ( ): The ratio of a circle's circumference Cto its diameter D.

Polar Coordinates: A means of denoting a point's location by use of its radialdistance from the origin and the angle it is from the x axis.

Radial distance: How far something is from the coordinate axes as measureddirectly out from the axes.

Retrograde Motion: The westward motion of the planets against the backgroundstars. In order to maintain the Earth's central location and a commitment to perfect

circular motion, geocentrists devised a set of epicycles (orbits within orbits) uponwhich the planets would rotate. The motion of the planet about its epicycle allowedfor the presence of retrograde motion. However, heliocentrists' Sun-centered modelhad no need for epicycles as retrograde motion could bee seen as one planet simplyovertaking another as they raced about the Sun.See Animation.

Right Ascension (RA): A heavenly object's position in the sky as measured inhours:minutes:seconds east (+) or west (-) from the vernal equinox.
http://ssd.jpl.nasa.gov/elem_planets.htmlhttp://ssd.jpl.nasa.gov/elem_planets.htmlhttp://ssd.jpl.nasa.gov/elem_planets.htmlhttp://www.davidcolarusso.com/astro/#retrohttp://www.davidcolarusso.com/astro/#retrohttp://www.davidcolarusso.com/astro/#retrohttp://www.davidcolarusso.com/astro/#retrohttp://ssd.jpl.nasa.gov/elem_planets.html


18/23

Semi-major axis:See ellipse.

Semi-minor axis:See ellipse.

Sidereal period: A planet's sidereal period is what many often think of as theplanet's year--the time it takes to make one full revolution about its orbit.SeeAnimation.

Sol: our sun.

Successive approximation: A numerical method by which a solution is found toan equation by substituting in guesses for the answer on both sides of the equation.The sides are evaluated and the first guess that produces a difference between thesides of less than a pre-defined tolerance is taken to be the answer.

Synodic Period: A planet's synodic period id the time between two identicalconfigurations in the sky as seen from Earth (e.g., the time between twooppositions).See Animation.

Transcendental equation: An equation for which a general solution cannot befound algebraically as it contains transcendental (non-algebraic) functions.

True Anomaly: The angle between the perihelion and the planet as measured in

the plane of its orbit.

Vector: A quantity consisting of both direction and magnitude (e.g., velocity).

Velocity: A measure of an object's motion that includes both the object's speed anddirection.

Vernal equinox: Both the date (around March 21st) on which the Sun crosses thecelestial equator moving northward and the point against the background stars

where this occurs.
http://www.davidcolarusso.com/astro/#ellipsehttp://www.davidcolarusso.com/astro/#ellipsehttp://www.davidcolarusso.com/astro/#ellipsehttp://www.davidcolarusso.com/astro/#ellipsehttp://www.davidcolarusso.com/astro/#ellipsehttp://www.davidcolarusso.com/astro/#ellipsehttp://www.davidcolarusso.com/astro/#siderealhttp://www.davidcolarusso.com/astro/#siderealhttp://www.davidcolarusso.com/astro/#siderealhttp://www.davidcolarusso.com/astro/#siderealhttp://www.davidcolarusso.com/astro/#synodichttp://www.davidcolarusso.com/astro/#synodichttp://www.davidcolarusso.com/astro/#synodichttp://www.davidcolarusso.com/astro/#synodichttp://www.davidcolarusso.com/astro/#siderealhttp://www.davidcolarusso.com/astro/#siderealhttp://www.davidcolarusso.com/astro/#ellipsehttp://www.davidcolarusso.com/astro/#ellipse


19/23

The most important planes in Astronomy celestial equator & the ecliptic

The positions of all heavenly bodies one usually given in terms of these planets taking the first point

ofMesha ( Arius ) as the initial point.

The celestial equator is a great circle of celestial sphere in which the place of earth equator cuts thecelestial sphere. The continuation of aprant path ofSUN is known ecliptic & the most important

reference circle is SKY, It is a great circle cutting the celestial equator at an angle of 23 . If two

points of the intersections are celestial equator and the ecliptic are known as first point ofArius vernal equinox and autumnal equinox respectively .

Vernal point = VASATH SAMA HORA 0

Autumnal point SHARTH SAMA HORA 180

vernal equinoxn1. (Earth Sciences / Physical Geography) the time at which the sun crosses the plane of the equatortowards the relevant hemisphere, making day and night of equal length. It occurs about March 21 inthe N hemisphere (Sept. 23 in the S hemisphere)2.a. (Astronomy) Astronomythe point, lying in the constellation Pisces, at which the sun's ecliptic

intersects the celestial equatorb. (Astronomy) the time at which this occurs as the sun travels south to north (March 21)

celestial equatorn.A great circle on the celestial sphere in the same plane as the earth's equator. Alsocalled equinoctial, equinoctial circle

(Astronomy) the great circle lying on the celestial sphere the plane of which is perpendicular to the

line joining the north and south celestial poles Also called equinoctialequinoctial circle


20/23

Equinox

An equinox occurs twice a year, when thetiltof theEarth's axis is inclined neither away from nor towards

theSun, the center of the Sun being in the same plane as the Earth's equator. The term equinoxcan also

be used in a broader sense, meaning the date when such a passage happens. The name "equinox" is

derived from the Latin aequus(equal) and nox(night), because around the equinox, the night and day have

approximately equal length.

At an equinox, the Sun is at one of two opposite points on thecelestial spherewhere thecelestial

equator(i.e. declination 0) and intersect. These points of intersection are called equinoctial points:

classically, the vernal point and the autumnal point. By extension, the term equinoxmay denote an

equinoctial point.

An equinox happens each year at two specific moments in time (rather than two whole days), when there is

a location (thesubsolar point) on the Earth's equator, where the center of the Sun can be observed to be

vertically overhead, occurring around March 20 and September 22 each year.

Although the word equinoxis often understood to mean "equal [day and] night", this is not strictly true. For

most locations on earth, there are two distinct identifiable days per year when the length of day and night

are closest to being equal; those days are referred to as the "equiluxes" to distinguish them from the

equinoxes. Equinoxes are points in time, but equiluxes are days. By convention, equiluxes are the days

where sunrise and sunset are closest to being exactly 12 hours apart.[2][3]
http://en.wikipedia.org/wiki/Axial_tilthttp://en.wikipedia.org/wiki/Axial_tilthttp://en.wikipedia.org/wiki/Axial_tilthttp://en.wikipedia.org/wiki/Earthhttp://en.wikipedia.org/wiki/Earthhttp://en.wikipedia.org/wiki/Earthhttp://en.wikipedia.org/wiki/Sunhttp://en.wikipedia.org/wiki/Sunhttp://en.wikipedia.org/wiki/Sunhttp://en.wikipedia.org/wiki/Equatorhttp://en.wikipedia.org/wiki/Equatorhttp://en.wikipedia.org/wiki/Equatorhttp://en.wikipedia.org/wiki/Celestial_spherehttp://en.wikipedia.org/wiki/Celestial_spherehttp://en.wikipedia.org/wiki/Celestial_spherehttp://en.wikipedia.org/wiki/Celestial_equatorhttp://en.wikipedia.org/wiki/Celestial_equatorhttp://en.wikipedia.org/wiki/Celestial_equatorhttp://en.wikipedia.org/wiki/Celestial_equatorhttp://en.wikipedia.org/wiki/Subsolar_pointhttp://en.wikipedia.org/wiki/Subsolar_pointhttp://en.wikipedia.org/wiki/Subsolar_pointhttp://en.wikipedia.org/wiki/Equinox#cite_note-1http://en.wikipedia.org/wiki/Equinox#cite_note-1http://en.wikipedia.org/wiki/Equinox#cite_note-1http://en.wikipedia.org/wiki/Equinox#cite_note-1http://en.wikipedia.org/wiki/Equinox#cite_note-1http://en.wikipedia.org/wiki/Subsolar_pointhttp://en.wikipedia.org/wiki/Celestial_equatorhttp://en.wikipedia.org/wiki/Celestial_equatorhttp://en.wikipedia.org/wiki/Celestial_spherehttp://en.wikipedia.org/wiki/Equatorhttp://en.wikipedia.org/wiki/Sunhttp://en.wikipedia.org/wiki/Earthhttp://en.wikipedia.org/wiki/Axial_tilt


21/23

There are other two important points ie., Summer Solstice & Winter Solstice. The time at

which the SUN is furthest from equator and appears pause before retuning .( The term solsticecan

also be used in a broader sense, as the date (day) when this occurs. The day of the solstice is eitherthe "longest day of the year" or the "shortest day of the year" for any place on Earth, because thelength of time between sunrise and sunset on that day is the yearly maximum or minimum for thatplace)

Note : Asolsticeis an astronomical event that happens twice each year when theSunreaches its

highest position in the sky as seen from the North or SouthPole. The wordsolsticeis derived from

theLatinsol(sun) andsistere(to stand still), because at the solstices, the Sun stands still

indeclination; that is, the seasonal movement of the Sun's path (as seen from Earth) comes to a stop

before reversing direction. The solstices, together with theequinoxes, are connected with the

seasons. In many cultures the solstices mark either the beginning or the midpoint of winter and

summer.

.
http://en.wikipedia.org/wiki/Sunhttp://en.wikipedia.org/wiki/Sunhttp://en.wikipedia.org/wiki/Sunhttp://en.wikipedia.org/wiki/Geographical_polehttp://en.wikipedia.org/wiki/Geographical_polehttp://en.wikipedia.org/wiki/Geographical_polehttp://en.wikipedia.org/wiki/Latinhttp://en.wikipedia.org/wiki/Latinhttp://en.wikipedia.org/wiki/Latinhttp://en.wikipedia.org/wiki/Declinationhttp://en.wikipedia.org/wiki/Declinationhttp://en.wikipedia.org/wiki/Declinationhttp://en.wikipedia.org/wiki/Equinoxhttp://en.wikipedia.org/wiki/Equinoxhttp://en.wikipedia.org/wiki/Equinoxhttp://en.wikipedia.org/wiki/Equinoxhttp://en.wikipedia.org/wiki/Declinationhttp://en.wikipedia.org/wiki/Latinhttp://en.wikipedia.org/wiki/Geographical_polehttp://en.wikipedia.org/wiki/Sun


22/23

A solstice that occurs on June 21, give or take a day or two, when the sun is vertically overhead the

231/2 north parallel.

The initial reference point vernal equinox is fundamental for obtaining position for the heavenly bodiesof the position of the staler body may be obtained either by the ecliptic assumption and declination by

considering the point of KADAMBA the longitude and from the point DHRUVA the latitudes.

KADAMBA is north pole of ecliptic ring ( top most point ).

The initial point does not occupy and fixed position among the stars it always moves back in the

western pole in the star heaven due to the precision of the equinox.

With an annual motion of about 50.3 completing the circle in about 26,000 years. The longitudes

measure in this system is called tropical longitude.

In Indian system in order to stabilize the Zodiac a point has been taken as origin ( Mesha ) which is

permanently fixed on ecliptic ( Sankranti patha ), so that co-ordination in the fixed stars in the sky

do not changed. This is known as side real longitude are nirayan longitude.

Nirayana longitude is summed up by Ayanamsha we get Sayana longitude , this movement of initial

0 (VE) is known as Ayanamsha and the angular distance has been fixed Nirayana longitude and

Syana longitude is known as Ayanamsha ( side real time recognized by Nirayana )

AE

VE


23/23

Note :

Ayanmsha is defined as the difference between Saayan and Nirayanlongitudes of heavenly bodies . Now-a-days,Saayan and Nirayan are

respectively translated astropical and sidereal , but their originalmeanings were different.(See below for definitions ofSaayan andNirayan and their difference fromtropical and sidereal).

Ayanamsa(Sanskrit ayana: ayana "movement" + aa"component"),

also ayanabhga (Sk. bhga "portion"), is theSanskritterm inIndian astronomyfor the amount

ofprecession.[1]

In astrology, this is the longitudinal difference between theTropical(Syana)andSidereal(Nirayana) zodiacs.

Ayanamsa is now defined as the angle by which the siderealecliptic longitudeof a celestial body is

less than its tropical ecliptic longitude. Ayanamsa is mostly assumed to be close to be 24 today,

according to N. C. Lahiri[who?] 23.85 as of 2000. This value would correspond to a coincidence of the

sidereal with the tropical zodiac in or near the year 293 AD, roughly compatible with the assumption

that the tradition of the tropical zodiac as current inWestern astrologywas fixed byPtolemyin the 3rd

century.

The sidereal ecliptic longitude of a celestial body is its longitude on theeclipticdefined with

respect to the "fixed"stars.

The tropical ecliptic longitude of a celestial body is its longitude on the ecliptic defined with

respect to thevernal equinox point.

Since the vernal equinox pointprocesseswestwards at a rate of about 50".29 per year (the rate has

been accelerating) with respect to the fixed stars, the longitude of a fixed body defined with respect to

it will increase slowly. On the other hand, since the stars "do not move" (this ignores the effect

ofproper motion) the longitude of a fixed body defined with respect to them will never change.
http://en.wikipedia.org/wiki/Sanskrithttp://en.wikipedia.org/wiki/Sanskrithttp://en.wikipedia.org/wiki/Sanskrithttp://en.wikipedia.org/wiki/Indian_astronomyhttp://en.wikipedia.org/wiki/Indian_astronomyhttp://en.wikipedia.org/wiki/Precessionhttp://en.wikipedia.org/wiki/Precessionhttp://en.wikipedia.org/wiki/Ayanamsa#cite_note-0http://en.wikipedia.org/wiki/Ayanamsa#cite_note-0http://en.wikipedia.org/wiki/Ayanamsa#cite_note-0http://en.wikipedia.org/wiki/Tropical_Astrologyhttp://en.wikipedia.org/wiki/Tropical_Astrologyhttp://en.wikipedia.org/wiki/Tropical_Astrologyhttp://en.wikipedia.org/wiki/Sidereal_astrologyhttp://en.wikipedia.org/wiki/Sidereal_astrologyhttp://en.wikipedia.org/wiki/Sidereal_astrologyhttp://en.wikipedia.org/wiki/Ecliptic_longitudehttp://en.wikipedia.org/wiki/Ecliptic_longitudehttp://en.wikipedia.org/wiki/Ecliptic_longitudehttp://en.wikipedia.org/wiki/Wikipedia:Avoid_weasel_wordshttp://en.wikipedia.org/wiki/Wikipedia:Avoid_weasel_wordshttp://en.wikipedia.org/wiki/Wikipedia:Avoid_weasel_wordshttp://en.wikipedia.org/wiki/Wikipedia:Avoid_weasel_wordshttp://en.wikipedia.org/wiki/Western_astrologyhttp://en.wikipedia.org/wiki/Western_astrologyhttp://en.wikipedia.org/wiki/Western_astrologyhttp://en.wikipedia.org/wiki/Ptolemyhttp://en.wikipedia.org/wiki/Ptolemyhttp://en.wikipedia.org/wiki/Ptolemyhttp://en.wikipedia.org/wiki/Ecliptichttp://en.wikipedia.org/wiki/Ecliptichttp://en.wikipedia.org/wiki/Ecliptichttp://en.wikipedia.org/wiki/Starhttp://en.wikipedia.org/wiki/Starhttp://en.wikipedia.org/wiki/Starhttp://en.wikipedia.org/wiki/First_point_of_Arieshttp://en.wikipedia.org/wiki/First_point_of_Arieshttp://en.wikipedia.org/wiki/First_point_of_Arieshttp://en.wikipedia.org/wiki/Precession#Precession_of_the_equinoxeshttp://en.wikipedia.org/wiki/Precession#Precession_of_the_equinoxeshttp://en.wikipedia.org/wiki/Precession#Precession_of_the_equinoxeshttp://en.wikipedia.org/wiki/Proper_motionhttp://en.wikipedia.org/wiki/Proper_motionhttp://en.wikipedia.org/wiki/Proper_motionhttp://en.wikipedia.org/wiki/Proper_motionhttp://en.wikipedia.org/wiki/Precession#Precession_of_the_equinoxeshttp://en.wikipedia.org/wiki/First_point_of_Arieshttp://en.wikipedia.org/wiki/Starhttp://en.wikipedia.org/wiki/Ecliptichttp://en.wikipedia.org/wiki/Ptolemyhttp://en.wikipedia.org/wiki/Western_astrologyhttp://en.wikipedia.org/wiki/Wikipedia:Avoid_weasel_wordshttp://en.wikipedia.org/wiki/Ecliptic_longitudehttp://en.wikipedia.org/wiki/Sidereal_astrologyhttp://en.wikipedia.org/wiki/Tropical_Astrologyhttp://en.wikipedia.org/wiki/Ayanamsa#cite_note-0http://en.wikipedia.org/wiki/Precessionhttp://en.wikipedia.org/wiki/Indian_astronomyhttp://en.wikipedia.org/wiki/Sanskrit

Astrology Notes 12

Documents

Transcript of Astrology Notes 12