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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: The Great Circle Challenge
From: Samuel L
Date: 2014 Dec 27, 04:05 -0800
From: Samuel L
Date: 2014 Dec 27, 04:05 -0800
Thanks, Gary. 'Gave it a try and it works.
Sam L.
Re: The Great Circle Challenge
From: Gary LaPook
Date: 2014 Dec 26, 17:59 -0800
A slightly shorter formula is to take the arc cosine instead of arc sine, then you do not have to do the subtraction from 90. The rest of the formula remains unchanged.
Your formula:
90-sin-1((sin(21d 57min) x sin(-41.5d) + cos(21d 57min) x cos(-41.5d) x cos(334d 10min))
Multiply the answer by 60
Slightly better formula:
cos-1((sin(21d 57min) x sin(-41.5d) + cos(21d 57min) x cos(-41.5d) x cos(334d 10min))
Multiply the answer by 60
