AYANAMSA

Whereas the earth and the other planets are very close to the Sun,

they are too far away from the constellations (groups of stars).

The distances of stars are measured in terms of light years.  Our

earth is only five minutes away from the Sun.

 

The earth's axis of rotation is inclined at an angle of 23 1/2° to the

ecliptic. Owing to the gravitational pull exerted on the equatorial

bulge by the luminaries and this inclination, the earth revolves like

a spinning top, its pole describing  a great circle (the Precessional

Arc) in space every 26000 years (a Great Year). The notation is

irregular and hence the variations in the lengths of Great Years

from 23000 to 26000 solar years.

THE TWO ZODIACS

The wobble causes shifting of the equinoxes backward in space.

During a Great Year, earth's pole aligns with different pole stars.

At present Polaris is the North-pole star. Because of

the precession of the equinoxes, the Tropical zodiac also moves

with respect to the constellations (stars), which remain fixed in

space several light years away. So, the sign Aries of the Tropical

zodiac, which commences at the vernal equinox, no more coincides

with the asterism called Ashwini, where the Sidereal zodiac starts.  

Moreover, the precessional movement is not uniform as we have

said earlier. Debate has been going on since the last century about

the exact precession of the equinoxes. (At present the Tropical

Aries coincides with 5° Sidereal Pisces.)

 While Western astrologers employ the Tropical Zodiac (moving)

Zodiac, which commences at the vernal equinox, in Hindu astrology

the starting point of the zodiac coincides with the asterism called

Aswini and hence the name Sidereal (fixed ) Zodiac. Though the

signs have the same names in both the zodiacs, the concepts are

quite different. The time when the two zodiacs coincided is not

exactly known. The rate at which the equinoxes move is also a

point of dispute.

Hence the need for taking into account, the Ayanamsa, which is

the difference in longitude between the two zodiacs.

…………………………………………………………………………………