A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Frank Reed
Date: 2016 Sep 3, 12:32 -0700
Amit Yaffe, you wrote:
"Is there a way to produce Sight reduction tables for air navigation (As in vol 1), using a python script or other means?"
Yes, there is. The current editions of Pub.249 vol.1, printed and sold by Celestaire, are available for epochs 2015 and 2020 (either can be used in the year 2016). The data for selected stars in these volumes is the official USNO data acquired by scripting from their online web app. For example, here is the data for LHA Aries = 0° and latitude - 40° for Jan 1, 2015: http://aa.usno.navy.mil/cgi-bin/aa_flamenav.pl?ID=AA&[...]. You can cycle through that to get any value of LHA Aries or Latitude (note that GHA Aries is identical to LHA Aries if longitude is zero). There are some details you have to deal with, like averaging out nutation, which I won't get into. You can also calculate this data directly from standard ephemeris data and the usual equations of positional astronomy. It's quite straight-forward. The data in the published volumes was checked by that direct calculation in every case.
Conanicut Island USA