Formula for calculating an Ephemeris table

Question

Here's an obscure question:

I need to be able to determine historical astrological periods (semi) accurately. I am looking for a way to calculate the start and end dates of a given zodiac sign period given a geographical coordinate and a year.

The purpose of the algorithm is to determine the possible dates of birth for a person whose astrological sign, year and place of birth is known for the Open Ancestry project. I will convert the implementation to C#.

Does anyone know of a semi reliable source for an existing Ephemeris table or a way to create one programmatically? I really just need a start point so it doesn't matter if the geographical parts of the formula or table are missing as long as the mechanism for approximating the start and end (given a specific year) are shown.

The programming language for an algorithmic approach is not important.

Answer 1

Why don't you look at the source of stellarium (was able to go quite far in the past)? I am sure the whole thing is an overkill for you, but maybe you can dig up their resources or contact somebody involved with it?