NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Antoine Couëtte
Date: 2013 Jan 31, 19:46 -0800
Re : [NavList] Re: Star Sha & Dec changes.
From: Sean C
Date: 31 Jan 2013 10:54
Byron,
As an example: For Spica in the year 1500, the SHA was ca. 165°15.0' and the Dec. was ca. S8°31.0'. Today's values are SHA: 158°31.4' Dec.: S11°13.8'. I used Stellarium (the program Frank recommended) to find these values.
Regards,
Sean C
******* ******* ******* *******
From an independent Software, using the latest IAU theories for Precession Nutation and from the SIMBAD Star catalog I can find :
Jan 01st, 1500 at 00:00 UT1 (with TT-UT=198.3 seconds of time : I know .... this one is quite totally superfluous ....)
SPICA (Apparent Equatorial Coordinates)
GHA = 274d11'0
SHA = 165d14'8
RA = 12h59m00.987s
DEC = S-8d30'25.880"
AP = 0.01306"
Paul, could you please crosscheck the results here-above, if you have time ? :-)
In view of the accuracy permitted by a Star-Finder, there are differences of some significance when compared with the Stellarium results : almost 3 degrees for SHA .... Any typo from your side, Sean ?
Best Regards to all,
Kermit
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