NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Nautical Almac Question
From: Bill B
Date: 2006 May 31, 14:14 -0500
GregR wrote
> Can anyone tell me why some of the "Eqn. of Time" entries in the Nautical
> Almanac are shaded and some are not? (A good example is the page for June
> 12, 13 and 14 where there's an example of both). I'm guessing that's
> related to the Equation of Time reversing sign (maybe the shaded entries are
> negative?), since the values seem to be decreasing up to June 13 and then
> increasing).
Excellent detective work. When shaded, GHA of the sun is less than the
nominal value (0d at 12 UT), and meridian passage is later than 12 UT. When
unshaded, GHA is greater the nominal value (0d at 12 UT), and meridian
passage is earlier than clock noon at Greenwich.
Bill
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From: Bill B
Date: 2006 May 31, 14:14 -0500
GregR wrote
> Can anyone tell me why some of the "Eqn. of Time" entries in the Nautical
> Almanac are shaded and some are not? (A good example is the page for June
> 12, 13 and 14 where there's an example of both). I'm guessing that's
> related to the Equation of Time reversing sign (maybe the shaded entries are
> negative?), since the values seem to be decreasing up to June 13 and then
> increasing).
Excellent detective work. When shaded, GHA of the sun is less than the
nominal value (0d at 12 UT), and meridian passage is later than 12 UT. When
unshaded, GHA is greater the nominal value (0d at 12 UT), and meridian
passage is earlier than clock noon at Greenwich.
Bill
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To post to this group, send email to NavList@fer3.com
To , send email to NavList-@fer3.com
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