NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Tinyac on Linux
From: Peter Monta
Date: 2017 Apr 3, 15:08 -0700
From: Peter Monta
Date: 2017 Apr 3, 15:08 -0700
Hi Bruce,
Or can someone recommend another program that provides apparent positions with sub-arcsecond accuracy, taking account of all the usual factors like height, temperature, pressure?
The planetarium programs may not be taking into account up-to-date estimates of UT1 and polar motion. Some reference implementations for astrometry are the packages NOVAS and SOFA and, more recently, Skyfield. Skyfield has a convenient and concise Python API and automatically queries IERS for the earth rotation parameters---I've used it for some theodolite astro reductions (I too have been bitten by this bug).
Sub-arcsecond accuracy in the vertical angle will depend on accurate knowledge of the troposphere all along the line of sight. I'm not sure it's realistic to do much better than a few arcseconds for moderately large zenith angles.
Cheers,
Peter
