NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Believe it or not
From: Alexandre Eremenko
Date: 2007 Jan 26, 13:43 -0800
From: Alexandre Eremenko
Date: 2007 Jan 26, 13:43 -0800
Here is more of the same. January 26, GMT 20:20, sunny weather strong wind T=44(F) P=29.1in Sun-Moon at approx 101 degrees. Pocket Troughton ans Simms, IC=0. GMT: 20:58:00 21:00:40 21:02:30 21:04:20 21:07:05 21:08:10 sextant reading: 101d40' 101d43' 101d41' 101d43' 101d44' 101d44' It was immediately clear (after the third observation, and CERTAINLY before the reduction) that the second observation was a blunder and I decided to discard it. Here is the sequence of errors, including the blunder (reduced with Frank's calculator): 0.0' , 1.8' , -0.9', 0.3, 0.2, -0.3. If one discards the blunder, the average error is -0.14, sigma=0.5, and if one does not discard, then the average error is 0.18 with sigma=0.9. Not bad for a 2 inch sextant:-) Here is SNO-T, for comparison IC=-0.5, I list the errors of 11 observations: -0.2, 0.3, 0.1, 0.4, 0.4, -0.2, -0.2, 0.3, -0.3, 0.1, -0.1 . Average error 0.05, sigma=0.3. The first 5 observations were made with filter number 1, and the last 6 with filter number 2. That filter number two gives a bit smaller reading than filter number 1 was known to me. It is hard to tell which of them is "right". If one computes the averages separately one gets 0.2 for the first filter and -0.1 for the second one. In the IC determination both filters were used, and average was taken. Alex. --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to NavList@fer3.com To , send email to NavList-@fer3.com -~----------~----~----~----~------~----~------~--~---