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    Re: Resume of "Averaging"
    From: Alexandre Eremenko
    Date: 2004 Nov 6, 22:34 -0500

    Dear Chuck,
    On your resume I have few little comments.
    
    1. In all this long discussion on Averaging,
    I never discussed the situation you describe
    (except the very last message yesterday).
    I was always talking of ONE body.
    And my point was shortly speaking that you can
    improve the precision and reliablity of ONE
    position line obtained from ONE body.
    
    2. On my opinion, the "fix" that is a pair of numbers
    (your latitude
    and longitude) is not the "ultimate goal" of Cel Nav.
    On my opinion, the ultimate goal is to know where you are.
    The information on your position that you can obtain
    from your observations is NOT reduced to
    these two
    numbers. Any observations give you really a "spot" not a "point"
    a spot where you probably are. The size and shape of this spot
    are also RELEVANT.
    
    3. What I would do with your data is this. I would average
    each star observation. Obtain 3 position lines.
    Draw them on the map (ALL three of them!) and write with a pencil
    on each line from how many observations was it obtained.
    (A line obtained from the average of several observations
    is nore reliable than a line obtained from one observation).
    
    For example, there could be a potential danger (a reef)
    on the West from my DR position. Then I will take every
    oppotrunity to observe a body whose azymuth is roughly West,
    or East, to obtain a position line in the N-S direction.
    
    4. Notice: I do not object the algorithm Herbert promotes.
    Though it seems suitable only for computer navigation,
    apparently he does not propose to do it by hands:-)
    
    But the fact that his algorithm is feasible in some
    circumetsnces for computer navigation does not
    justify his sweeping statements that "averaging is the thing
    of the past" that "aweraging is always wrong" etc.
    
    It is only these strange statements that I strongly
    object.
    I call them "strange" because I have never heard or read anything
    like this before (though I read much on the subject),
    and I could not imagine a person familiar with the subject
    making such statements.
    
    A
    
    
    

       
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