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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Testing SNO after fixing
From: Fred Hebard
Date: 2005 May 28, 18:37 -0400
From: Fred Hebard
Date: 2005 May 28, 18:37 -0400
On May 28, 2005, at 5:27 PM, Alexandre Eremenko wrote: > Fred, > You wrote: > >> By my calculations with your two sets of sights, the mean and >> standard deviation of Ho-Hc in minutes of arc were 0.096 +/- 0.195 >> and 0.032 +/- 0.137. Were your previous sights this precise? > > I did not reduce each sight. Only the averages. > My previous obsrvations with art horizon were generally less > precise. And many of them showed systematic error (overshot). > Same happened with star distances, with a larger error. > > What does the second number (after +/-) in your message mean? > Maximal deviation from the average or standard deviation? > (I suppose the first number is the average Ho-Hc). The second number is the standard deviation of Ho-Hc and the first number is the average or mean of Ho-Hc. In print, the mean and standard deviation usually are separated by a plus sign (+) directly over the minus sign (-). Since that's not possible in the 128-bit ascii of email, I used "+/-" as a substitute. Did the master at Freiberg clean the arc and worm on your sextant? Bill just posted about an effect of a dirty arc on accuracy. Fred
