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Re: BS XM DS Daytime Venus, Redux
From: Henry Halboth
Date: 2011 Jan 19, 13:44 -0800
From: Henry Halboth
Date: 2011 Jan 19, 13:44 -0800
Jeremy, The correction procedure for a Back Observation can become a little complicated, particularly in Solar observations. It is probably best to diagram the situation carefully, as opposed to blindly following rules, so as to understand the problem fully with respect to the necessary reversal of dip and IC signs, as well as proper handling of the SD depending on the true Limb observed, the LL becoming the apparent UL and vice verse.. I have done only a few back sights, specifically in war time convoys, where intervening ships might obscure the horizon, or off poorly charted coastal areas, with no means of ascertaining distance off (no radar) to facilitate a short dip solution. Should you be interested, I have attached several pages from my notebook which rather fully detail the problem and associated corrections. The apparent contradictions between a quadrant and a sextant apparently originate in the assumption that the quadrant be fitted with a back sight mirror and peep sight while the sextant is not. Regards, Henry --- On Tue, 1/18/11, Anabasis75@aol.com <Anabasis75@aol.com> wrote:
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