NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Peter Hakel
Date: 2010 Mar 9, 14:43 -0800
Peter Hakel
From: Brad Morris <bmorris@tactronics.com>
To: NavList@fer3.com
Sent: Tue, March 9, 2010 1:48:30 PM
Subject: [NavList] Star - Star Observations
[patrs deleted by PH]
Here is the dilemma. When I get to larger angles, I need to go beyond my zenith. For example, I have been looking at Polaris vs Sirius. My latitude is about 40 degrees north. So Sirius is to my south, Polaris, naturally, is to my north. The nominal distance works out to about 106 degrees 20 odd minutes (forgive me, I don’t have the exact numbers in front of me). Because each object is on either side of my zenith, both objects will appear to be lower in the sky compared to the horizon, due to refraction. Yet because they oppose each other in azimuth, the observable distance between them should be larger by the sum of the refraction corrections, not reduced by the difference of the refraction corrections. That is, compute the true distance without refraction. Since each object is lowered by refraction, but in opposite directions, shouldn’t we add the refraction corrections to the nominal distance to obtain the observable distance?
Best Regards
Brad
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