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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Possible limitaion for lunar distance measurement
From: Frank Reed
Date: 2009 Feb 27, 16:37 -0800
From: Frank Reed
Date: 2009 Feb 27, 16:37 -0800
Kent, you wrote: "in this manual it is stated that it is only possible (or feasible) to use the lunar distance method if the distance is between 70 and 110 degrees. " Historically, this is generally the case. But the reasons are practical, not mathematical. Mostly, the Sun was the "other body" for lunar observations. And the results were generally better when the Moon was around first or last quarter which would be when the distances were in the range you gave: 90 degrees, plus or minus twenty. You would have three or four days to shoot lunars twice a month. In practice that was enough. By the way, one should take comments on lunars from those later years (like 1906) with a grain of salt. Lunars were entirely obsolete at sea, and some of the textbook advice from that era was muddled. -FER --~--~---------~--~----~------------~-------~--~----~ Navigation List archive: www.fer3.com/arc To post, email NavList@fer3.com To , email NavList-@fer3.com -~----------~----~----~----~------~----~------~--~---