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Re: Old style lunar
From: Frank Reed CT
Date: 2004 Dec 10, 01:31 EST
From: Frank Reed CT
Date: 2004 Dec 10, 01:31 EST
Fred, you wrote:
"The only one that's somewhat serious is Nov 14, 1778, and that's out
by
25" of arc. This can't explain discrepancies of 1 degree of arc!"
25" of arc. This can't explain discrepancies of 1 degree of arc!"
Maybe I should have mentioned that I simply picked a few dates totally at
random, to give a taste for the sorts of discrepancies you might find...
some days very close, other days significantly out of line, and I should add
with no periodicity (which would be easy to correct).
Here's what Maskelyne has to say about the matter in the preface
to the Nautical Almanac that year:
"These new tables [...] seem to give always the Moon's longitude in the
Heavens correctly within 45 seconds of a degree; which greatest error, added to
the possible error of one minute in taking the Moon's distance from the Sun or a
star at sea, will at a medium produce an error of 50 minutes of
longitude".
Frank R
[ ] Mystic, Connecticut
[X] Chicago, Illinois
[ ] Mystic, Connecticut
[X] Chicago, Illinois
