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Re: Longitude Sight Calculation with Ageton Classic?
From: Lars Bergman
Date: 2023 Aug 28, 02:31 -0700
From: Lars Bergman
Date: 2023 Aug 28, 02:31 -0700
Herman, yes it is possible to calculate local hour angle with those tables.
First, calculate the auxiliary variable s = (90° + ALT + LAT ± DEC) / 2, where the plus sign is used when LAT and DEC has different names, otherwise use the minus sign. Then calculate s - ALT.
Now, A(±LHA/2) = [ B(s) + A(s-ALT) - B(LAT) - B(DEC) ] / 2. An example:
LAT = 55° N
DEC = 14 N
ALT = 29°
s = (90° + 29° + 55° - 14°) / 2 = 160° / 2 = 80°
s - ALT = 80° - 29° = 51°
A(±LHA/2) = [ B(80°) + A(51°) - B(55°) - B(14°) ] / 2 = [ 76033 + 10950 - 24141 - 1310 ] / 2 = 61532 / 2 = 30766
±LHA/2 = 29°30'
LHA = ±2 · 29°30' = ±59° = 59° or 301°, depending on whether the body is west or east of the observer's meridian.
Lars
