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    Aldebaran occultation
    From: Alexandre Eremenko
    Date: 2017 Mar 5, 05:14 +0000

    This evening I observed Aldebaran's occultation by the Moon.
    I had to use a binocular (8x30) because Aldebaran was obscured by the Moon light and
    not visible with the naked eye since about one hour before the occultation.
    
    The moment of disappearance I timed as March 5, 3:56:48 (GMT)
    using a stopwatch started from the GMT web site. The disappearance was sudden, 
    very sharp, as a lamp switched off,
    and I am sure that I timed it correctly.
    
    Then I entered the data to Frank's online calculator
    40d27.2'N, 86d55.8'W
    IC 0
    T=32
    P=29.8
    Distance: 0, near limb.
    
    To my surprise I obtained the error -0.2' in the distance.
    Playing with the calculator shows that it gives zero distance for the time from 3:57:52 to 3:58:36,
    which is more than 1 minute later than I observed.
    
    How to explain this disagreement? 
    
    The re-appearance is more difficult to time, again because of the Moon light obscuring the star.
    When I noticed it it was about 4:39, but it was already at some visible distance from the Moon surface.
    Frank's calculator shows that reappearance happened between at about 4:36.
    
    Alex.
    

       
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