NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
MkIXa bubble sextant performance
From: Alexandre Eremenko
Date: 2007 Apr 04, 19:01 -0700
From: Alexandre Eremenko
Date: 2007 Apr 04, 19:01 -0700
After a month of practice, I can find my position within 2-3 miles with this sextant. The use of the averager gives better results than a single observation. But averaging 5 single observations by hand gives the same precision as the mechanical averager does (it averages 60 observations). Here is a typical complete fix with the averager: GMT April 3, 1:28:46 Sirius 28d22' ; 1:51:55 Venus 15d18'.5 Using DR 40N, 87W, I obtain Alt of Sirius 28d44'.2, Azimuth 207d, Alt of Venus 15d12'.8, Azymuth 282d. Correcting for refraction and plotting on the Universal Plotting Sheet gives this position 40d20'.5N, 86d54d.5W, as read from the plot with 0'.5 resolution. My true position was 40d27'.2N, 86d55.8W, so the error is slightly more than 1 mile. In this reduction I used the Complete on Board Celestial Navigator, which is not very precise but very handy indeed. Here are two typical series of individual observations (averager off, reduced with the Almanac and computer). Venus, errors: 1'.8, -2'.4, -0'.9, -0'.2. Sirius, errors: 1'.2, 1'.7, 3'.0, 0'.0, 1'.8. Alex. --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to NavList@fer3.com To , send email to NavList-@fer3.com -~----------~----~----~----~------~----~------~--~---