NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Precision of lunars
From: Frank Reed
Date: 2007 Apr 25, 23:28 -0400
From: Frank Reed
Date: 2007 Apr 25, 23:28 -0400
Alex, you wrote: "Can you cite or post ANY data or statistics" uh... sure! With a good, well-adjusted sextant, I get a standard deviation for Moon-Sun lunars, and of 0.2 minutes of arc on individual sites. On sets of four, averaged, I get an s.d. of 0.1 minutes of arc. For Moon+other object brighter than magnitude 0.5, I get similar results. With fainter stars, the results are progressively worse (bear in mind that something like 80-90% of the historical lunars I've seen in logbooks are Sun-Moon lunars). These results haven't changed in years for me, but it all depends on the sextant. It has to be an instrument that has been well-adjusted, tested for arc error, made of metal (no plastic sextants for lunars!), and carrying a telescope with a magnification of 7x or better. Now, if you want to see data for individual sights, I posted many series during the 3.4 years I've been on the list. You can search the archive if you want: www.fer3.com/arc -FER --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to NavList@fer3.com To , send email to NavList-@fer3.com -~----------~----~----~----~------~----~------~--~---