A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Sean C
Date: 2015 Aug 10, 21:04 -0700
When working my own sights, I almost always do a quick check using the formula at the top of the pdf that Ron posted. This is the same simple formula cited in the Nautical Almanac: 0.28P/(T+273); where P=pressure in mb and T=temp. in °C. It only takes a few seconds with a handheld calculator to see if the additional correction is worthy of consideration.