NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Averaging
From: Alexandre Eremenko
Date: 2004 Oct 21, 18:28 -0500
From: Alexandre Eremenko
Date: 2004 Oct 21, 18:28 -0500
Bill, I think the "rule of thumb" you are requesting was posted in my previous message. Several messages I read after that seem to confirm it. The rule is roughly the following: the averaging will improve the precision of your result EXCEPT in the following situation: A body near the meridian AND on high altitude. If the body is two compass points away from the meridian everything is fine. If a body is lower than 60d everything is also fine. So in MOST cases of altitude measurement, the averaging of the altitudes (over 5 min interval) is justified. For the Lunar distances it is probably ALWAYS justified. The rules for the altitudes refer to the situation where the expected single measurement error is about 05' or more. For those who care about 0.1' (say on land, with artificial horizon etc.) the rules have to be modified: you have to be further away from the meridian if the altitudes are high. Alex. On Thu, 21 Oct 2004, Bill wrote: > My questions were, how much error from averaging is acceptable, > and is there > a rule of thumb for estimating how much error there will