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    Re: Pointer star question
    From: Richard B. Langley
    Date: 2013 Feb 03, 00:46 -0400

    PyEphem, the Python equivalent of XEphem, gave the result as  
    34:04:12.3. As viewed from Fredericton at 22:00 UTC using a standard  
    atmosphere, PyEphem computed the separation as affected by refraction  
    as 34:02:43.0 with the refraction on Polaris' altitude of 46:37:17.5  
    being 0:00:53.9 and that on Marek's altitude of 20:47:34.9 being  
    0:02:30.0.
    
    Wolfram Alpha can compute the separation between celestial bodies too:
    http://www.wolframalpha.com
    and enter "angular separation between polaris and merak on 2 February  
    2013 at 22:00 UTC"
    But the result was a bit off:
    34 degrees 4 arc minutes 12.89 arc seconds
    Differences here (and with USNO-computed values) can be due to  
    different precisions of the J2000 coordinates for the stars and the  
    differences in precision and accuracy of the various algorithms for  
    updating the coordinates to the equator and equinox of date.
    
    -- Richard Langley
    
    
    Quoting "Richard B. Langley" :
    
    > According to the program XEphem, at the moment, the separation is 34°04'12"
    > -- Richard Langley
    >
    > Quoting Mark :
    >
    >> Hello all! I've been a lurker for several years now but I've been
    >> unable to find an exact answer the angular separation between
    >> polaris and merak, does anyone know what it is?  Thanks, Mark.
    >> ----------------------------------------------------------------
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    >> View and reply to this message: http://fer3.com/arc/m2.aspx?i=122230
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    >
    >
    > -----------------------------------------------------------------------------
    > | Richard B. Langley                            E-mail: lang---ca         |
    > | Geodetic Research Laboratory                  Web: http://www.unb.ca/GGE/ |
    > | Dept. of Geodesy and Geomatics Engineering    Phone:    +1 506 453-5142   |
    > | University of New Brunswick                   Fax:      +1 506 453-4943   |
    > | Fredericton, N.B., Canada  E3B 5A3                                        |
    > |        Fredericton?  Where's that?  See: http://www.fredericton.ca/       |
    > -----------------------------------------------------------------------------
    >
    >
    >
    >
    >
    > View and reply to this message: http://fer3.com/arc/m2.aspx?i=122237
    
    
    
    -----------------------------------------------------------------------------
    | Richard B. Langley                            E-mail: lang@unb.ca         |
    | Geodetic Research Laboratory                  Web: http://www.unb.ca/GGE/ |
    | Dept. of Geodesy and Geomatics Engineering    Phone:    +1 506 453-5142   |
    | University of New Brunswick                   Fax:      +1 506 453-4943   |
    | Fredericton, N.B., Canada  E3B 5A3                                        |
    |        Fredericton?  Where's that?  See: http://www.fredericton.ca/       |
    -----------------------------------------------------------------------------
    
    
    
    
    

       
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