NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: 1768 Almanac
From: Frank Reed CT
Date: 2007 Apr 18, 18:09 -0700
From: Frank Reed CT
Date: 2007 Apr 18, 18:09 -0700
Dave W wrote: "setting the observation site to Greenwich Observatory and itererating to find local apparent noon for 14 Jan 1768, one finds UTC to be 12h 9m 31.626s." etc. Just a reminder, the lunar distance predictions on my web site ALREADY provide the lunar distance tables in Greenwich Apparent Time (or Greenwich Mean Time if prefered) for any date. You can set it to produce tables with distances in degrees, minutes, and tenths or in degrees, minutes, and seconds. The latter allows direct and immediate comparison with the published tables. This online tool has been available for exactly this purpose for some three years now. Enjoy! For example, looking at a page from the Nautical Almanac for 1778, we see listed lunar distances from the Sun of 124d 0' 4", 110d 40' 2", 97d 29' 7" at noon GAT on October 10, 11, 12 respectively. By my calculator, the correct distances were actually 123d 59' 58", 110d 39' 41", 97d 28' 36" so the errors are 0.1, 0.35, 0.5 minutes of arc corresponding to longitude errors of approximately 3, 10, and 30 minutes of arc. -FER www.HistoricalAtlas.com/lunars --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to NavList@fer3.com To , send email to NavList-@fer3.com -~----------~----~----~----~------~----~------~--~---
