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    Ex-Meridian Sight using Inmans
    From: David C
    Date: 2020 Jun 10, 03:01 -0700

    Although it is just under two weeks to the winter solstice today was a perfect day for CN. The sky was blue, there was absolutely no wind and the temperature was a comfortable 14°C.  I took a few practice sights using the anti-spoof app and also took a noon sight. Rather than work the noon sight or calculate intercepts for the other sights I decided to  reduce an early PM sight by the ex-Meridian tables in Inmans (1932).

    The meridian altitude was  51° 19' in an AH.

             51°   19'

           IC       -4

              51 15

    /2  25 37.5

    SD/R    +14.1'

    Ho = 25°   51.6 '   ----noon altitude

    The PM sight was  UT 01 05 46     49°  30' 50"

    Following the  procedure above ho = 24°  57.5'    --------PM sight

    Now calculate apparant time

    DR long = 175° 05.2'

    UT 01 05 46

                       195°  08.1'

    increment        1°   26.5'

       GHA         196° 34.6'

    Add E long   175°  05.2'

         LHA          371°  39.8'

                       - 360°

                           11°  39.8'

    Inmans does nor have an arc to time table so I used Norie.......

       Apparant time 0h 46m 40s  PM

    Time of noon was 01 05 46    -  0h 46m 40s  = 00 19 06 which agrees with app on my phone.

    Now calculate ex=meridian correction....

    Table 1  9.888

    Table2   8.009

    Sum     17.897

    From Table 3 correction = 54.2'

    A second correction from table 4 is -0.2' so the correction is 54'

    Finally compare the calculated correction with the actual

      ho noonsight - ho pm sight  =  54.1'

    This remarkable agreement suggests either luck or that my errors are systematic, not random, and that they cancel out on subtraction of the two altitudes!

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