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    Re: sun sights
    From: Fred Hebard
    Date: 2011 Jan 30, 19:59 -0500

    Patrick,
    
    I'm glad to hear that tectonic forces are not too aggressive in the
    vicinity of your garden.  I'm at about the same latitude, but 81* 50'
    W, and found out the same thing about the deck attached to the back
    of my house, much to relief of my family!
    
    I didn't work through all your sheet, but your assumed longitude for
    the first sight is 76* 7.2' W when the GHA would suggest that 62* 7.2
    W is correct.
    
    I started out with HO 229, but then moved to computerized reduction
    to focus on my sextant technique.  By the time I had the technique
    down, I was too lazy to go back to hand calculations!
    
    One thing I did find was that accurate timing, to the second, is
    critical. I used the difference between the observed altitude and the
    calculated altitude as a metric of accuracy.
    
    Fred
    
    
    On Jan 30, 2011, at 7:40 PM, Patrick Goold wrote:
    
    > Dear Nav-listers,
    > This is boring compared to recent lunar observations, but I am
    > still trying to determine the position of my front garden using sun
    > sights.  As advised by several of you, I moved past using meridian
    > passage.  On Saturday I took three sights one approximately an hour
    > before LAN, one at LAN and one approximately one hour after.  I
    > then reduced the sights using H.O. 229 (which I discovered is a lot
    > like doing your taxes) and plotted the results on a universal
    > plotting sheet.  The plot showed that the altitude intercepts of
    > the second and third sight intersected at a point very close to my
    > GPS long/lat.  The first one, however, seemed out.  I ran my data
    > through the on-line sight reduction calculator at  www.celnav.de/sightred.htm> and it confirmed the problem.  I cannot
    > find my mistake.  Worksheet attached.  All assistance gratefully
    > received.
    >
    > BTW, the garden is, relatively speaking, stationary.
    >
    > Best regards,
    > Patrick
    >
    >
    > Charles Olson: "Love the World -- and stay inside it."
    >
    > <29 Jan sunsights.pdf>
    
    
    
    
    

       
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