A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Position-Finding
From: Ken Muldrew
Date: 2004 Jun 1, 19:55 -0600
Frank Reed wrote: > 2) I can't see where you got a factor of 1/2 out of > Maskelyne's instructions. There *is* a factor of 1/2 but it's folded > into the "8.73" factor. That factor (besides the 1/2) arises from > working in minutes and seconds of arc instead of pure angles (a.k.a. > radians). You'll find that 8.73 is pi/360 (with a factor of 1000) > which is why Maskelyne says to "abate 13" from the index instead of > the more common 10 or 20. I got the factor of 1/2 from the "abate 13", 10 for the log cotangent and 3 for a factor of 2. Anyway, it's all clear to me now. Thanks for the explanation. Ken Muldrew.