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    Re: Lunars: A 90 Degree Miracle
    From: Frank Reed CT
    Date: 2004 Nov 2, 01:44 EST
    George H wrote:
    "Take a simple case. The Moon is at an altitude of 45 degrees on one side of the sky. The other body is at 45 degrees on the other side of the sky, so that their azimuths differ by 180 deg. [minor typo fixed]
    The lunar distance, in that case, is 90 deg. Does Frank claim that in such
    a geometry, errors in the Moon's altitude correction, resulting from errors
    in its altitude, would have no effect?"

    Yes. That's the "miraculous" thing. Errors in the altitude correction are compensated by the change in azimuth. If the objects are "really" both at 45 degrees altitude and 90 degrees distance then when I work the calculation I will find that the difference in azimuth is 180 degrees. But if I measure 45 deg for the other body and by some accident measure 40 degrees for the Moon's altitude,  the difference in azimuth will be more like 147 degrees. The change in relative azimuth cancels out the change in the altitude correction.

    Frank R
    [ ] Mystic, Connecticut
    [X] Chicago, Illinois
       
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