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    Re: Celestial position-finding on land
    From: John D. Howard
    Date: 2016 May 3, 13:29 -0700

    Bob,

    I think that Lewis & Clark have be badmouthed over the years for poor sextant skills but I think that it is not deserved.  Pres. Jefferson instructed them to record and bring back the cel-nav data to Washington and a math person would do the sight reductions.

    Before going West the two explorers were given a quick cel-nav course by Robert Patterson and Andrew Ellicott.  Patterson had developed a method of Lunars where you do not need to measure the altitude of the moon and the star or sun.  His method #4 calculated the altitudes from an asumed lat & long.  He thought this was easier for land explorers because they would not have to set up the mecury artifical horizon when doing a luner.

    When Lewis and Clark got back to Washington their data wa given to Ferdinand Hassler, a professor at West Point.  Hassler could not do the lunars thinking information was missing and declared that the two explorers messed up.  Hassler apperentarly did not know Patterson's methiod #4.

    In recent years a man naned Robert Bergantino used the log books of L & C and used method #4 and calculated Lat and Long for the expidation.  He said the data was very close to the moderen values.

    A Richard S. Preston of N. Illinois U. has written an excellent paper on the Lewis & Clark sextant data. The paper can be found on the internet.

    John H.

       
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