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    Re: Hughes Tables.
    From: Douglas Denny
    Date: 2009 Jul 16, 21:05 -0700

    Hughes Tables were a re-assessment of all the other tables in use with a 
    re-arrangement of the tabulations for better use for air navigators.
    
    The explanation on page xxxi goes into some detail:-
    
    " It was originaly proposed to base Table I on the values of K and A given by 
    Weems (based on Ogura up to Latitude 65) and the values of D and Z1 given by 
    Dreisenstok.  However, in the course of the proof reading, comparisons were 
    made with published tables (Aquino,  Dreisenstok, Gingrich, Ogura, Pinto, 
    Smart and Shearme, and Weems)  showed that none of them, with the exception 
    of Aquino, were reliable.  In order to present tables whose error was less 
    than one unit of the last decimal in K and A, and less than half a unit in D 
    and Z1, many discrepancies had to be investigated by new calculations, 
    especially of the quantity A;  the entire portion from latitude 62 to the 
    pole was recomputed.
    It is curious that an obvious check has been missed by by all the other authors except Aquino. "
    
    ========================
    
    Working the values you gave:  It is not clear what longitude you wish to use 
    to give a local hour angle of a whole degree for use in the tables.  I used 
    the nearest which gives an LHA of 4 degrees.
    
    You gave Lat 40 N.  Long 77W. fomalhault  on 13th July 2009 at 09-00Hrs.
    
    I found the following:-
    
    Using ICE 0.51 for the ephemeris data for formalhaut for 13th July 2008 09-00Hrs:-
    
    GHA is 81-49.6
    Dec is S. 29-34.0    (N.B. ICE gives an Hc for the Lat40  Long 77W of 20-17.3)
    
    Working with Hughes:-
    We have:-
    
    GHA   81-49.6
    long  77-49.6 West (-)
    LHA   04-00
    
    K: (Table I)  +39-04.1
    declination   -29-34.0 (add to form K alt d)
    (K alt d)      68-38.1  (entered into Table II for 'B')
    
    A: (Table I)   00064
    'B'(Table II)  43850 (add)
    forms:  'C'    43914 ...... re-entered in Table II gives Altitude: 21-20'.0
    
    ===========================
    
    Douglas Denny.
    Chichester.  England.
    
    
    
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