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    Re: Precision of lunars
    From: Frank Reed CT
    Date: 2007 Apr 24, 02:43 EDT
    Alex, you asked:
    "do you object his statements about the accuracy of the lunars
    that I cited?
    If yes, what are your corrections to these statements,
    and what evidence can you give to support them?"
    Lord Kelvin's comments, I would say, accurately describe the accuracy of typical lunar distance observations around 1815 --combining the effects of observer error, sextant error, and almanac error. They do not apply today. Evidence? My own lunars. The lunars that a group of us did at Mystic in September, 2005. The lunars I've seen beginners shoot when they have a well-adjusted sextant in their hands. Etc.
    You're still not getting very good results, and you're content to believe, following Kelvin, that angles cannot be measured to better than 0.5 minutes of arc accuracy with a sextant. Looking with a 7x or 10x telescope, an angle that large is very obvious. With the limiting resolution of the human eye (corrected) somewhere around 0.7 to 1.0 minutes of arc, the limiting resolution through a ten power telescope is around 0.1 minutes of arc. So we can certainly "see" angular shifts smaller than 0.5 minutes of arc. What's your latest theory on the reasons you've been unable to do as well as you would like with your observations?
    42.0N 87.7W, or 41.4N 72.1W.

    See what's free at AOL.com.
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