Moving dates of the Capsolar

[SteveS]

Jim, do the dates of the Capsolar move through all the days in our 365 days calendar in a complete Precession Cycle?

[Jim Eshelman]

Yes.

[SteveS]

Can you easily approximate the date of the Capsolar in 10,500 BC?

[Jim Eshelman]

Can you easily approximate the date of the Capsolar in 10,500 BC?

That was 12,446 years before 1947. A crude calculation of the amount of precession is 173° degrees later, so the SVP was about 29° Leo. Therefore, in 10,500 BC Sun's Tropical longitude for the Capsolar would have been:

Sidereal longitude 270° - 149° SVP = TZ 81° = TZ 21° Gemini.

In the New Style (Gregorian) calendar, this is always about 9 days before the summer solstice, or within a day of June 12. I'd have to find a New Style to Old Style conversion for that far back to get the Julian (OS) date.

[SteveS]

Thanks Jim. Forgetting the 10,500 BC date and going with a more modern date, approximately when last did the Capsolar date fall on a Winter Solstice date?

[Jim Eshelman]

221 AD