Wednesday, August 13, 2008

Ayanamsha and Other Software Calculations

> Dear Narasimha,
> >
> > Thank you for your exposition. Currently I am unsure about your
> newly proposed ayanamsa. For example in the chart of Pandit Sanjay
> Rath the Moon sign changes in D9, 12, and 24 (at a quick glance) and
> in other's charts also I have observed that this can be a very
> dramatic change.
> > Nevertheless I wanted to discuss a couple of the Tithi Pravesha rasi
> charts you mentioned that are mostly the same regardless of which
> Lahiri ayanamsa you use.

From: Narasimha P.V.R. Rao <>
Date: 2008/8/13

Of course, it can be a "dramatic change" when a planet is on a border. With Lahiri ayanamsa, Sanjay ji's Moon is just below 20 deg in Aq, i.e. just at the end of Satabhishak.
If ayanamsa is reduced by merely 1 arc-min, it takes Moon above 20 deg and changes his nakshatra, navamsa, drekkana, dwadasamsa, siddhamsa, shahstyamsa etc.
The issue is not that this ayanamsa changes things "dramatically". It actually changes things only by a few arc-min at the most and that is not "dramatic". The issue is that a planet is on a critical boundary in this chart.
In such a case, whether you accept my proposed fixed-plane ayanamsa or not, the bottomline is that you cannot be confident that the ayanamsa you are using is perfect and not having even 1 arc-min of error. Even if ayanamsa is perfect (how can you be so sure), a change in birthtime by 2 min can change Moon's longitude to above 20 deg. Thus, you cannot be too sure of Moon's nakshatra, navamsa etc.
People often take the calculations of software to be perfect and assume that everything is known perfectly. That is wrong. People should realize that each parameter (birthtime, ayanamsa etc) could have an error and realize the impact on various calculations. When a specific calculation is on a border, one should consider both the cases. We do that kind of analysis all the time in my Boston class.
BTW, I and Sanjay discussed several years ago whether his star is Satabhishak or Poorvabhadra (because it is right on the border). Sanjay wasn't sure then, but said that his grandfather thought his star was Poorvabhadra!
Best regards,
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