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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Averaging
From: Bill B
Date: 2004 Oct 20, 18:09 -0500
From: Bill B
Date: 2004 Oct 20, 18:09 -0500
> As Herbert Prinz quite rightfully pointed out, there are exceptions > where one indeed could introduce systematic error in excess of the > random error that is removed, so one has to be cautious. As I continue to look at 4 minutes spreads and averages, I have shifted my focus to the Hc 10d-20d range. Here, even with a 20d-30d difference between latitude and declination I am getting a big 4-minute spread, in the range of 45'-55', indicating approx. .6'-.7' averaging error. Herbert was indeed kinder to me with his numbers than he could have been. I won't make a value judgment as to whether that is too much shift for a particular navigator and/or under what circumstances. My question, is there a rule of thumb that might indicate when averages are acceptable and when not. For example, for error of .4' or less (due totally to systematic errors from averaging) difference between latitude and declination, plus altitude should exceed 60d (or any other number that the gurus decide is reasonable? Thank you Bill