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    Re: Sextant Accuracy and anomalous dip.
    From: Jared Sherman
    Date: 2003 Mar 17, 23:20 -0500

    Arthur-
     If I understand this correctly then, when the air is warmer than the sea, the 
    observed altitude is too small. And conversely when the sea is warmer, the 
    observed altitude is too large.
     But one minute per six degrees F seems like it is big enough so that it 
    should have been a "routine" correction in sight reductions, rather than some 
    obscurity to be dug out of an old Bowditch. With a winter ocean near 32F on a 
    cold 5F day...that's an easy 4-5 minute error in the readings! Ditto for 
    those lazy days when the water is near 70F but the air has been pushing the 
    high 90's and local heat from a beach seems to be boiling the air even more.
    
     It just seems odd that an error of this magnitude would be routinely ignored.
    
    
    

       
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