When it comes to astrology, you can never know too much about the Planets - the Grahas. The ancient texts provide information about the Grahas in the form of Sutras. A Sutra is short and precise in its meaning, but has many, many ramifications. Sutras provide information that. Ayanamsha, or ayanamsa is the exact difference in degrees between the moving vernal equinox and the exact sidereal zero Aries point. There are differing values; the Lahiri, Raman, etc, determined by different criteria. It's basically the exact degree offset of the tropical zodiac from the sidereal zodiac.
Ayanamsa - A Scientific Calculation
Data used is from scientific community and not from Vedic text books.But Vedic Seers have to be credited for noting this great scientific data namely Ayanamsa or Precession of Equinox, astronomically long back. This is the greatest Achievement of Vedic Sidereal Astrology and Astronomical observations in India from time immemorial.
Calculation of Ayanamsa using Modern Astronomical Data
Polaris (Alpha UMi) or Urs Major or Dhrurva nakshatra or the Pole star is the present reference star for measuring the precession of Earth or Ayanamsa.
North Ecliptic Pole (NEP) is 90 degree of center of Equator of Earth.
The Earth tilt is about 23 degrees 26 min 11.8 seconds (23.43661 degrees). Again this changes slightly due to Earth nutations, but more or less constant. So, North Celestial Pole (NCP) of Earth is in a tilt of 23.43661 degree with NEP of Earth.
Also the Polaris star is tilted from NCP (NCP-Polaris tilt) by 0.736 degrees away. This value will change according to Earths nutation and Polaris own motion.
Scientifically according to mathematical calculation, NCP will point and will be closet to Polaris in 2140 AD.
The full precession circle of Dhurva or Polaris nakshatra, scientifically is 25,771.58 Julian years. In Hindu terminology it is 25,770 years.
The scientific accumulated precession formula for 2000 as the epoch Julian year is
AP = 5,028.796195 + 2.2108696 × T in ArcSeconds, T being the Julian centuries.
So to use this above formula, we need to know when the tropical and sidereal zodiac coincided.
25771.58 minus 2140 years will take us back in time, when Polaris was in same position as it will be in 2140, meaning NCP will be exactly pointing to Polaris with zero tilt with NCP, that is (25771.58 - 2140) = 23631.58 julian years back.
So the total Julian years expended from that NCP-Polaris-Zero year, is used to calculate the total accumulated precession.
23631.58 plus 2000 = 25631.58, will enable us to use above formula for Epoch 2000 which is the scientific formula for Accumulated precession.
Accumulated Precession (AP) in ArcSecondsAP = 5,028.796195 + 2.2108696 * ( 23631.58 minus 2000) / 365.25)dividing with 365.25 is done to convert normal number of years to Julian years.
The values got from above has to be added to the actual tilt of Earth w.r.t to Dhurva nakshatra on that day, i.e. Epoch 2000.
Why add, one may ask, it is because the Earth arrives later (Or Sun arrives earlier) to same point on celestial plane around Sun, due to this precession.
Adding 23.43661 tilt degree (between NCP and NEP) will give Ayanamsa for Epoch 2000.
So, Ayanamsa = 23.43661 + (AP / 3600). AP is divided by 3600 to convert Arcseconds to degrees for Epoch 2000.
So the perfect scientific Ayanamsa formula for 2000 AD year is
- For birth year before 2000 Epoch
Ay = 23.43661 + (5,028.796195 + 2.2108696 * ( 23631.58 + (2000 - Birth Year) / 365.25)) / 3600
- For birth year after 2000 Epoch
Ay = 23.43661 + (5,028.796195 + 2.2108696 * ( 23631.58 + ((2000 - Birth Year) + (Birth Year - 2000)) / 365.25)) / 3600
The slight changes in Earth tilt (Axial Tilt) changes between 22.1 and 24.5 degrees on a scale of 41000 years. Couple compatibility astrology tests.
and Polaris actual degree away from NCP now (40 arcminute or 0.736 degree away), again changes in few arcseconds, needs to be taken into consideration, which would be another calculation for another day for me.
If these two (Axial Tilt and NCP-Polaris Tilt) changes are taken into account, according to that Birth Year, it will make the aynamasa accurate in seconds. For that I need astronomical data, funds and my energy and time. Already I am too old.
In this class we will discuss pertinent information relative to the Ayanamsa, Nakshatras and the Rasis. This will be an astronomically centered class during which I will discuss the results of my researches into these most paramount astrological topics, which are the very foundation of the science.
I discuss some very controversial issues in this class, some of which may cause you to revisit your horoscope in an entirely new way. If you would like to discuss your chart or any other charts that you may be testing for purposes of seeing which calculations are more accurate, please feel to call me (760-420-5648) or Email Me and we can set up a time to discuss it. I am offering this service free of charge because I consider the calculations that us astrologers use to be of greatest importance and so I am always happy to discuss them or to examine charts in light of the different calculation possibilities.
Before you listen to this class, make sure you read the following article and download the following diagrams, otherwise the class will not make much sense.
Ayanamsa and Rasis Class (To listen to this Free Jyotish Class, click on link to listen right away, or right click on the link and select Save Target As to save it to your computer for future listening.)
What exactly are the Nakshatras? How are they different than Rasis?
What exactly are the Rasis?
What Ayanamsa is both scientifically sound and works best in practice?
Tropical Vedic Astrology Chart Calculator
What types of Vedic Years are there and which should be used for what purpose, including what works best for Dasa calculation?