A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Francis Upchurch
Date: 2016 Jan 1, 11:02 -0800
Yes, I understand the limited accuracy required for the near meridian ex meridian for Hc and the calculated Hc bit of the lunar. But I think Letcher is saying his 10" trig rule is ok for the LD0 bit of the lunar formula and I'm very confused about that, since he says , on the same page you have to work to 0.1' and need full NA and not the Short tables. So I've stopped using the Bygrave and BN for lunars and only use the Fuller 2 which gives results essentially the same as a calculator (well, to 4-7 places).
Maybe I've missed some esoteric mathematical point here?