NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Mike Mayer
Date: 2014 Mar 22, 12:28 -0700
Hi,
Anyone know what I'm missing? In comparing the Sun's GAST - RA from the Astronomical Almanac to the GHA in the Nautical Almanac there are cases that seem to be too far off. For example, for January 1, 2014 at 0 UT I get:
GAST = 6h42m17.0580s = 6.704738333h (Page B13)
RA = 18h45m35.31s = 18.759808333h (Page C6)
GAST - RA = -12.055070000 = 11.944930000h = 179.17395° = 179°10'26.22"
= 179°10.437'
The Nautical Almanac has 179°10.2'
The difference is 0.237', which is outside the accuracy the Nautical Almanac specifies for the GHA Sun data in the paragraph numbered 24 on page 261 of the commercial version of the Nautical Almanac 2014.
What am I missing ?
Thanks!
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