Modern Lahiri Ayanamsa formula

[CARRIERE Francois]

Hello everyone and Seasons' Greetings,

I once saw somewhere a formula to calculate manually the ayanamsa according
to Lahiri which took into account the variation of precession. I can not
find it. I wonder if it is not Mr Axel Harvey who share it once? Can someone
share the formula if he has it? Thank you.

[CARRIERE Francois]

Post by CARRIERE Francois
Hello everyone and Seasons' Greetings,
I once saw somewhere a formula to calculate manually the ayanamsa
according to Lahiri which took into account the variation of
precession. I can not find it. I wonder if it is not Mr Axel Harvey
who share it once? Can someone share the formula if he has it? Thank
you.

Hello,

Finally, I have found my formula, using Lahiri on 2000.0. It was in a
preface of Axel Harvey in a book that was written in 2000 by Jean-Paul
Michon. The formula is:

A = 23:51:25 + 50.291" * t + 1.11161" * T.

Where t is number of years since 2000.0 (negative before); T is number of
centuries of 36525 days from 2000. Noon time.

Now, I wished the formula could match the Swiss Ephemeris :-(

[Marty]

Post by CARRIERE Francois

Post by CARRIERE Francois
Hello everyone and Seasons' Greetings,
I once saw somewhere a formula to calculate manually the ayanamsa
according to Lahiri which took into account the variation of
precession. I can not find it. I wonder if it is not Mr Axel Harvey
who share it once? Can someone share the formula if he has it? Thank
you.

Hello,
Finally, I have found my formula, using Lahiri on 2000.0. It was in a
preface of Axel Harvey in a book that was written in 2000 by Jean-Paul
A = 23:51:25 + 50.291" * t + 1.11161" * T.
Where t is number of years since 2000.0 (negative before); T is number of
centuries of 36525 days from 2000. Noon time.
Now, I wished the formula could match the Swiss Ephemeris :-(
--
Best regards,
François

Because you have to apply nutation, periodic variation involving the
lunar node.

NU = -17.20" * SIN(ND) - 1.32" *SIN(2*L) - 0.23" * SIN(2*L1) + 0.21" *
SIN(2*ND)

where:

ND = longitude of lunar node
L = mean long of Sun. L= 280.4665+36000.7698 * T
L1= mean long of Moon. L1 = 218.3165 + 481.8813 * T

Add NU to A as in your above formula.

As you can see nutation can vary precession nearly +/- 19"

Martin

[CARRIERE Francois]

Hello Martin,

Thank you for the precision ;-)