NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Equation for dip?
From: Frank Reed CT
Date: 2006 Sep 26, 07:34 EDT
From: Frank Reed CT
Date: 2006 Sep 26, 07:34 EDT
Of course the equation for dip is based on a standardized assumption about terrestrial refraction. If the lapse rate (rate at which the air cools with height) varies a bit from the mean, then the constant in the dip equation changes. You can trust the standard formula or the standard tables in the great majority of cases to +/- 1.0 minutes of arc, and commonly to +/- 0.2 minutes of arc. But it's not better than that. Dip is not exact! -FER 42.0N 87.7W, or 41.4N 72.1W. www.HistoricalAtlas.com/lunars --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to NavList@fer3.com To , send email to NavList-@fer3.com -~----------~----~----~----~------~----~------~--~---