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    Re: Lunar Distances with Alex's SNO-T
    From: Alexandre Eremenko
    Date: 2006 Oct 31, 22:00 -0500

    
    Dear Frank:
    You wrote:
    
    > Yesterday, October 29,...
    > First I did a series of index correction sights
    > off the Moon.
    
    Why did not you use the Sun?
    
    > Carefully aligning the Moon images pole-to-pole, my
    > observations were (on arc, off arc):
    > 33.1, 31.7
    > 32.9, 31.3
    > 32.7, 31.4
    > 32.8, 31.2
    > Subtracting and averaging, I settled on
    > an index correction of -0.75
    > minutes of arc.
    
    Adding and averaging gives 64.275.
    While according to the Almanac, true Moon SD
    for October 29 was 15.8, which gives 4DS=63.2.
    So you are off by the whole minute.
    
    So much of the Lunar IC correction.
    Or do I confude something?
    
    I just tried to repeat this experiment with
    IC from the Moon. After VERY careful measurement
    I obtain
    On: 32.3, 32.4, 32.3, 32.2
    Off: 33.5, 33.6, 33.5, 33.6.
    This gives 4SD=65.85, while the true 4SD this evening
    is 65.2 where I took the average SD between
    October 31 and November 1 because it is about midnight
    in Greenwich now.
    
    The result is off by 0.6.
    
    Now I derive from my data IC=0.7 which also seems absurd.
    From stars I found today that IC is close to zero,
    and this is confirmed by a reasonably good Lunar.
    
    So I am very skeptical about using the Moon for
    IC correction.
    
    Alex.
    
    
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