NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Checking a sextant calibration.
From: Paul Hirose
Date: 2003 Oct 6, 19:41 -0700
From: Paul Hirose
Date: 2003 Oct 6, 19:41 -0700
Paul Hirose wrote: > > Just pretend I'm from Missouri and show me your method with a fully > worked example. Answering my own challenge, here's a fully worked example of one simple way to check a sextant's calibration. Position 40 41.4' N 074 02.7' W (accurately determined by GPS or other means) Time 2003-10-07 14:12:53 UT Sun Ho 32 17.6' Submit the position and time into this USNO Web page: http://aa.usno.navy.mil/data/docs/celnavtable.html It says the Sun's Hc = 32 16.9', so our Ho was .7 minutes greater than expected. But remember, that discrepancy isn't just instrumental error. It includes errors in the applied refraction and dip, and personal error. Based on that one data point, I'd say there doesn't seem to be anything seriously wrong.