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    Lunars and the Astra IIIb
    From: Eric Haberfellner
    Date: 2001 Dec 15, 5:37 PM

    I have acquired a copy of Bruce Stark's "Tables for Clearing the Lunar
    Distance and Finding G.M.T. by Sextant Observation" and am planning to try
    this ancient and noble art some time in the new year.
    Is the Astra IIIB a reasonable instrument to attempt this with? In the
    preface, Mr. Stark mentions that "0.1' of error in the distance causes about
    twelve seconds of error in Greenwich time". Now, I do not know of a sextant
    with a guaranteed accuracy of 0.1' (6"). The best that I know of is the
    Cassens and Plath with a guaranteed accuracy of +/- 9" (0.15'). The Astra
    IIIb has a stated accuracy of +/- 20" (.33'). Does this mean that it is
    reasonable to attempt to determine GMT to an accuracy of about 50 seconds
    with an Astra IIIb?
    I would also be interested in hearing from others who have tried using Mr.
    Stark's tables.
    Eric Haberfellner

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