NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Stellarium and the heavens in the 17th century
From: Frank Reed CT
Date: 2006 Dec 1, 07:42 EST
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From: Frank Reed CT
Date: 2006 Dec 1, 07:42 EST
Guiseppe, you wrote:
"if you are interested I tested Deneb, Aldebaran, and Polaris on Dec
1° 1770
(6 GMT) using my software based on Swiss Ephemeris and Moshier Ephemeris. I
used it very satisfactorily for the last three years with continuous
testing.
I found the following results very close to those of the stellarium"
(6 GMT) using my software based on Swiss Ephemeris and Moshier Ephemeris. I
used it very satisfactorily for the last three years with continuous
testing.
I found the following results very close to those of the stellarium"
Thanks. Yes, that's interesting.
Could I ask you to try one more case please. For June 1, 1804 at 0600 GMT,
what do you have for the Declination of Arcturus? My software says it
should be 20d 12' 17" (and the US Naval Observatory seems to agree: http://aa.usno.navy.mil/data/docs/celnavtable.html).
The Stellarium software has 20d 06' 02". That's over six minutes of arc
difference, detectable even with primitive navigational instruments.
My best guess: I believe that Stellarium ignores proper motion and also
annual aberration. These things can be fixed... maybe someone will pass this on
to the authors of the software.
-FER
42.0N 87.7W, or 41.4N 72.1W.
www.HistoricalAtlas.com/lunars
42.0N 87.7W, or 41.4N 72.1W.
www.HistoricalAtlas.com/lunars
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