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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: What's "under the hood" of the Raft Book?
From: Greg Rudzinski
Date: 2017 Oct 21, 13:05 -0700
From: Greg Rudzinski
Date: 2017 Oct 21, 13:05 -0700
Tony,
Perhaps there was a different defenition for length of day when the Raft Book was written. Anyway it would be a very crude way to determine latitude. I would rather take a guess at Polaris altitude. See link to the NOAA calculator for length of day which might be of use as a checker for anyone attempting timing trials.
https://www.esrl.noaa.gov/gmd/grad/solcalc/sunrise.html
Greg Rudzinski
From: Tony Oz
Date: 2017 Oct 21, 11:04 -0700Greg, thanks for the comment and the kamal implementation.
My question was why Mr Gatty tabulated the -31' Hc rather than the apparently more correct value of -51'?
Regards,
Tony
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