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    Re: Back In Hobby: Some Questions, Please
    From: Fred Hebard
    Date: 2007 Apr 27, 17:34 -0400

    This was in the tropics, was it not?  If he's getting latitude by
    noon observation, then the altitude of the sun is very high and the
    artificial horizon doubles the angle.  Not only do arc errors often
    increase dramatically at high angles, but it's much more difficult to
    even see the sun in the index mirror.  It's difficult to achieve
    conjunction of the bodies with an artificial horizon, more so than
    using a natural horizon.  I wonder why he didn't just walk down to
    the beach and use that, depending on it's orientation.
    
    Fred
    
    On Apr 27, 2007, at 5:26 PM, Ken Muldrew wrote:
    
    >
    > On 27 Apr 2007 at 10:59, Alexandre E Eremenko wrote:
    >
    >> But the errors in LATITUDE are enormous by comparison:
    >> 48', 6', 0', -1', 5', 5', 11', -2', -9', 0, -2', +4',
    >> This is not what I would expect from artificial
    >> horizon observations, even with a poor sextant.
    >> Even if we discard the 2 outliers (possibly some blunders)
    >> the average absolute error is 3.4' which is too large.
    >>
    >> Is it possible that some poor quality wood octant was used
    >> for the altitudes, and a metal sextant for the lunars?
    >
    > No, he clearly states that he only has the one, metal sextant with
    > him on
    > that trip. It may have been a problem with his artificial horizon
    > (non-
    > parallel glass, for example) or else he just missed the noon sight
    > due to
    > the demands of his party. I have no other explanation for why his
    > latitudes were so poor.
    >
    > Ken Muldrew.
    >
    > >
    
    
    
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