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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: venus
From: Herbert Prinz
Date: 2004 Oct 10, 15:09 -0400
From: Herbert Prinz
Date: 2004 Oct 10, 15:09 -0400
Michael Dorl wrote: > 89.50 west 42.85 north > altitude 290 meters > temperature 5 degrees C > tick.usno.navy.mil time 6-13-06 CDT 11-13-06 Greenwich I agree with Frank Reed that the near limb was illuminated, but my own computation for it agrees better with George Huxtable's value for that limb. George observes correctly that the Moon is about to overtake Venus, which is consistent with the GHAs he posts, but then slips in picking the far limb. My distances for date and location above, 11:14:10 ET deltaT = 64.4 are center Moon / center Venus geoc. 17? 00' 42.4" near limb Moon / center Venus topoc. no atmosphere 16? 06' 01" near limb Moon / center Venus topoc. 5?C/1010mbar 16? 05' 08" I can post intermediate results from my computations, if Michael Dorl finds that helpful for debugging his program. I would have to recompile mine with some traces for that purpose. Frank and I should probably also compare work. 0.4' seems too much of a difference. I notice that my results disagree with HORIZONS between 2 and 8 seconds of arc, either because I am using DE200 and they are using DE406, or maybe a different refraction model (At least I hope it's nothing more severe.) Herbert Prinz