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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Sun Moon Lunars to 155 degrees
From: George Huxtable
Date: 2010 Apr 2, 09:35 +0100
From: George Huxtable
Date: 2010 Apr 2, 09:35 +0100
Brad Morris wrote- > Finally the calculator states an error of 3.8 minutes in Moon altitude > and 3.4 minutes in the Sun's altitude. In attempting to use 3.6 minutes > as an index correction, it is shown that the error in alitudes are in > opposite directions. > Best Regards > Brad and Bill Noyce responded- Perhaps that supports the idea that the altitudes were measured simultaneously with the lunar distance, using two separate octants? -- Bill N. ======== I don't really agree with any of that. Remember, lunar-distance is an inexact science, and there's plenty of scope for scatter in the result. In this case, the lunar distance being so large, the Moon and Sun are both low in the sky; one to the East, and rising (this being from the tropics) at about 15º per hour, the other falling in the West at a similar rate. Any error in predicted GMT from the lunar will put one higher, and the other correspondingly lower. So any discrepany between the calculated altitudes tells us little about the errors in observing those altitudes. George. contact George Huxtable, at george@hux.me.uk or at +44 1865 820222 (from UK, 01865 820222) or at 1 Sandy Lane, Southmoor, Abingdon, Oxon OX13 5HX, UK.