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    Re: Lewis and Clark lunars: more 1803 Almanac data
    From: Ken Muldrew
    Date: 2004 Apr 19, 16:10 -0600

    On 18 Apr 2004 at 23:50, Paul Hirose wrote:
    
    > Right ascension of the star would be 4 h 50 m by my calculation.
    
    I had another look at a star chart over lunch and found a small, dim,
    red star at the bottom of Orion's bow (PI 6 Orion) with an 1803 right
    ascension of 4h 48m 23.5s, dec 1? 24' 5.7". I stuck that into my
    spreadsheet where I was comparing the cleared distance with the true
    distance for various stars (in my post of this morning) and it
    appears to be our mystery star. Perhaps through a good telescope a
    magnitude 4.47 star can look like Aldebaran? Here are the results of
    my calculation for PI 6 Orion:
    
    GMT     clr'd d true d
    5.094   59.697  59.605
    5.323   59.758  59.705
    5.493   59.831  59.795
    5.589   59.839  59.831
    5.643   59.923  59.865
    5.694   59.938  59.888
    7.267   60.544  60.625
    7.362   60.619  60.680
    7.419   60.600  60.698
    7.490   60.607  60.732
    7.525   60.636  60.757
    7.571   60.638  60.770
    
    The error for the first run (series A) averages out to about a
    minute, well within the expected limit. The error for the second run
    (series C) is a bit larger, and increasing, so they may indeed have
    used another nearby star for this series as George has speculated,
    although the error is comparable to what they got for Regulus in
    series B.
    
    Ken Muldrew.
    
    
    

       
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