NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Greg Rudzinski
Date: 2013 Apr 8, 14:04 -0700
If you are having bad luck with planet and Moon LOP's but good star and Sun LOP's then look closely at how the v and d correction is applied ( and HP for the Moon ). Check the GHA sum from the Nautical Almanac to the USNO GHA value. If there is more than 0.1' difference then investigate. I will bet the culprit is the v.
I bring this up because yesterdays twilight observation of Jupiter had me scratching my head because of a difference of 1.5' between USNO GHA and the NA GHA and well wouldn't you know it the v increment correction hadn't been applied. Extra care is needed for the Moon since the v and d increments can be large ( over 10' ).
Greg Rudzinski
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