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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Lunar-distance almanac errors [was; The Online Nautical Almanac- beware!]
From: Frank Reed CT
Date: 2004 Jul 13, 17:34 EDT
From: Frank Reed CT
Date: 2004 Jul 13, 17:34 EDT
George H wrote:
"What they have left us is more often just a deduced
longitude. That deduced longitude is affected by
1. any errors in their measurements.
2. any errors in their data reduction process.
3. any errors in the nautical almanac tables.
We can not do much about the first two, but if we know those errors in the
tables, it would allow us to adjust out their effect on the deduced
positions by a corresponding amount, without knowing any details of how the
longitude was arrived at."
Aha. Yes, I can see some value to that. Thanks!
Frank R
[ ] Mystic, Connecticut
[X] Chicago, Illinois
"What they have left us is more often just a deduced
longitude. That deduced longitude is affected by
1. any errors in their measurements.
2. any errors in their data reduction process.
3. any errors in the nautical almanac tables.
We can not do much about the first two, but if we know those errors in the
tables, it would allow us to adjust out their effect on the deduced
positions by a corresponding amount, without knowing any details of how the
longitude was arrived at."
Aha. Yes, I can see some value to that. Thanks!
Frank R
[ ] Mystic, Connecticut
[X] Chicago, Illinois