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    Re: Longitude at noon
    From: Tracy Shrier
    Date: 2020 Sep 9, 10:05 -0700

    Hi Phillip,

    Monday I took my first marine sextant noon sight off an artificial horizion in my back yard, today I read your post, funny coincidence! Attached is my work up for your interest. You're seeing my raw data as directly recorded and reduced so I apologize for the sloppy writing. Some notes on my sight and workup:   I used water in the artifical horizon box which caused some issues noted. With the artifical horizon the raw hs is double a horizon sight (hsx2 column). I simply halved the hsx2 minutes for a spreadsheet plot not shown, but do correctly show hs at LAN - 54°54.2'. For simplicity this first time I did not correct hs to Ho, but looking at it now I belive that r is the only correction I would need to make ( -1' from table 6 in the Air Almanac). Lastly, being an aviator, I use the Air Almanac for the GHA calculation for latitude. 

    For my NavList friends that are wondering where the bubble sextant is - I retired a month ago, no more sights from the cockpit. I'm going sailing in the San Juan's first of October with an old friend, so I'm trying to quickly teach myself nautical techniques and picked up a Davis MK25 to have some fun with. Hopefully you won't consider Lat within 6 miles and Long within 22 miles too terrible for my first try :)


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