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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@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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