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RE : http://fer3.com/arc/m2.aspx/Sirius-another-precession-theory-FrankReed-aug-2013-g24920

Hello Frank and Others,

From current theories (Precession IAU 2006 (P03) and Nutation IAU 2000A) and from the SIMBAD Star Catalog (ICRF Reference) :

- For Jan 01st, -9500 00:00 UT (using TT-UT = 410,033.2 s) I find Sirius apparent declination S -54°05'14"4, and

- For Jan 01st, -9300 00:00 UT (using TT-UT = 395,671.6 s) I find Sirius apparent declination S -53°10'16"1 .

Too many non-significant printed digits given here-above, I know :-) , but these can be useful as a crosscheck to whoever would be using the same computation sources.

These results seem consistent with the story that "Then around 9300 BC it would have peeked above the horizon right at the meridian" since I just found that this Anatolian site has a Latitude close to N36°

What is the actual reliability of my results hereabove ? I probably used P03 Nutation (slightly?) out of its useful domain, so the declinations achieved here might be only accurate to maybe not better than 30', with their error most certainly not exceeding 60' in the very (very, very) worst case. However even with such assumed inaccuracies, the results hereabove would still be somewhat meaningful.

Another way to compute Sirius position more accurately would be to use a better long term Precession theory.

I have heard that the P03 Precession theory has been further extended to very long intervals (exceeding +/- 200,000 years around J2000) into a quite reliable theory lately described as " New precession expressions, valid for long time intervals[1] J. Vondrák1, N. Capitaine2, ! , and P. Wallace3 " . The declination values given here-above could certainly be further reliably validated againts the results of such new theory.

I would also think that the declination values here-above can also be crosschecked through the SOLEX Software, although I have not attempted doing it myself.

CONCLUSION : In theory, yes !, what you summarize here-above makes sense, Frank.

In practice ? ........... would Sirius so low on the horizon have been so bright as it is now when high in the sky ? Even from a hill the horizon light/brightness attenuation due to the Earth Atmosphere absorbtion would definitely have precluded observing such dramatic (very) bright "grazing star rises/star sets". Also by such remote period in the past, was Sirius really brighter than it is now ? I remember having read an article indicating that for some period in the past, Lady Sirius (although quite bright much later than 9500 BC, i.e. during the extraordinary amazing and remarkable Aegyptian Civilisation) did not look so bright as it currently shines nowadays.

Your thoughts here ???

Best Regards

Kermit

which apparently is a recent and quite solid and reliable precession theory which extends the current
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