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    Re: Lunar distance accuracy
    From: Alexandre Eremenko
    Date: 2007 Oct 23, 22:26 -0400

    
    Frank,
    Indeed, I missed the paper of White.
    Thanks for sending me a link.
    I am collecting experimental data on
    Lunars accuracy, and will soon post the combined statistics.
    
    Alex
    
    On Tue, 23 Oct 2007 frankreed{at}HistoricalAtlas.net wrote:
    
    >
    >
    > Alex, you wrote:
    > "These are all data I have. I will be very grateful if someone points to any
    > other hard data or research on the subject."
    >
    > You may have missed the article by E.J. White from 1889 that I described on
    > the list almost a year ago --I know you get busy now and then and don't
    > follow the list as closely as you would like. Here's a paragraph from my
    > post back then:
    >
    > "White then details the lunar distance observations he has made in the past
    > three years: forty-two lunars in 1887, 1888, and 1889. He lists the time and
    > measured distance (only approximately, not enough detail to re-work them
    > today) and also lists the error of the resulting longitude in seconds of
    > time. We can convert this to an approximate error in the measured lunar by
    > dividing by 120. That is, an error of 12 seconds in the longitude is
    > approximately equivalent to an error of 0.1 minutes of arc in the measured
    > lunar distance. Calculating from his listed numbers, I find he has a
    > standard deviation in Greenwich time of about 30 seconds which is equivalent
    > to about 0.25 minutes of arc in the lunar distances. If we take his lunars
    > in sets of four and average them (which I consider the best approach with
    > lunars), the results are generally within 0.1 minutes of arc. I would note
    > that these results are very similar to my own experience."
    >
    > The original post is here:
    > http://fer3.com/arc/m2.aspx?y=200611&i=101759
    >
    > As noted then, I found White's article originally while digging around in
    > Google Books. Since it's short, I've also made it available on the web here:
    > www.HistoricalAtlas.com/lunars/ejwhite.
    >
    >  -FER
    > www.HistoricalAtlas.com/lunars
    >
    >
    >
    > >
    
    
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