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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Pear shaped Earth
From: Peter Fogg
Date: 2002 Oct 3, 07:33 +1000
From: Peter Fogg
Date: 2002 Oct 3, 07:33 +1000
David Weilacher wrote: > My conclusion from this is that a pear shaped earth has a negligible effect on > the accuracy of sight reduction. It doesn't matter what distance you are from > the center of the earth (well there is an over-simplification) as long as the > horizon is also at the same level. Since the horizon is likely to be only 4 > to 10 nm away, this pear shape notion becomes moot because you and the horizon > are at the same height. > Agree with this. > so, if I've understood correctly, a degree at > 10d of lat.is 59.71 nm, and a > degree at 90d of lat. is 60.007 nm. Woke up in the middle of the night, an attack of logic: if the earth bulges out at the equator and is flattened at the poles, then shouldn't a degree, expressed as nm, be longer at the equator and shorter at the pole?
