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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Real accuracy of the method of lunar distances
From: Geoffrey Kolbe
Date: 2004 Jan 16, 08:05 +0000
From: Geoffrey Kolbe
Date: 2004 Jan 16, 08:05 +0000
George. I think you are arguing that even though the apparent motion of the moon has slowed due to parallactic retardation, GMT is derived from the true motion of the moon. The true motion of the moon is against the fixed stars is roughly constant and therefore the accuracy of the lunar distance method should be unaffected by parallactic retardation. The key point here is that parallactic retardation is a function of altitude only. It is not a function of time. It is therefore possible to derive a true lunar distance from an apparent lunar distance with an accuracy that is effectively time invariant. The larger the parallactic retardation, the larger the correction effectively applied to correct for it. If this is what you are saying George, I am with you. Geoffrey Kolbe. Border Barrels Ltd., Newcastleton, Roxburghshire, TD9 0SN, Scotland. Tel. +44 (0)13873 76253 Fax. +44 (0)13873 76214.
