NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: A Lunar
From: Geoffrey Kolbe
Date: 2008 May 30, 18:06 +0100
From: Geoffrey Kolbe
Date: 2008 May 30, 18:06 +0100
> >| >| >When discussing lunars and their accuracies, list members should be >careful >| >to state whether they are discussing / observing lunars taken at sea or >| >lunars measured from on land. There are significant differences. >| > >| >George. >| >| Are the differences in accuracy just due to the fact that lunars at sea >are >| taken from a platform that is not completely stable George? Or is there >| something else involved? >| >| Geoffrey Kolbe > >No, I had nothing else in mind, other than that instability, and the >difficulties it causes in achieving the necessary precision. . > >George. My experience in doing lunars is limited on land and zero at sea. But my impression is that the main difficulty is holding the sextant at a more-or-less horizontal angle which, because it was not designed to be so held, leads quickly to a rapid 'tremor' due to muscle fatigue. At sea, on a vessel whose weight is four figures of tons rather than yachts, which bob about with only single figures in tons, I would have thought the slow movement of the vessel (in reasonable seas) would have been much less of a problem and so contribute much less to the errors of the measurement than the fatigue of holding a heavy, unwieldy instrument. Comments, anyone...? Geoffrey Kolbe --~--~---------~--~----~------------~-------~--~----~ Navigation List archive: www.fer3.com/arc To post, email NavList@fer3.com To , email NavList-@fer3.com -~----------~----~----~----~------~----~------~--~---