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Subject: Re: Pear shaped Earth
From: Peter Fogg (ffive@XXX.XXX)
Date: Wed Oct 02 2002 - 17:33:44 EDT
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?
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