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