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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: Giuseppe Menga
Date: 2006 Dec 1, 13:58 +0100
From: Giuseppe Menga
Date: 2006 Dec 1, 13:58 +0100
You will be happy:
for Arcturus June 1, 1804 at 6:00 GMT My program says:
decl. 20°12' 17.4''
Giuseppe
----- Original Message -----From: FrankReedCT@aol.comTo: NavList@fer3.comSent: Friday, December 01, 2006 1:42 PMSubject: [NavList 1800] Re: Stellarium and the heavens in the 17th centuryGuiseppe, 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"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
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