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    Sun Backsights
    From: Jeremy C
    Date: 2011 Jan 20, 07:09 EST
    I am trying to get the hang of these back sights, so I decided to go back to basics and take a look at the sun.
     
    It was about 35 minutes before transit when I took these shots.  Due to my schedule and available azimuths with a sea horizon, I decided to do this instead.  I reduced them as straight LOP's because they are outside the acceptable limits of the ex-meridian tables.
     
    I took one sight that appeared to be a lower limb which is actually an upper limb observation.  I then repeated the sight but took what appeared to be an upper limb observation which was actually a lower limb.
     
    Date: 20 January 2011
    ZD-6
    Lat 07-16.3'S
    Long 072-26.8E
    HoE 106 ft
    IE 0.8 on the arc.  Normal IC is -0.8'
     
    Back Sight 1, Sun (UL)
    Time 12h 49m 19s Local
    Hs 104d 54.9'
     
     
    My Intercept using my GPS fix as the AP is 0.7 towards 150.0 degrees for sight 1
     
    Back Sight 2, Sun (LL)
    Time 12h 50m 20s
    Hs 105d 20.7'
     
    For sight 2 I had an intercept of 0.3 Away 150.5 degrees.
     
    As an interesting note that these sights tie into the recent discussion about the tabulation of the "d" correction.  If you check the bottom of the sun column, the "d" is 0.5.  However the hourly change for this observation is 0.6'/hour.  I used the 0.6 for my entering argument as I normally do.
     
    Jeremy
     
       
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