Some astonishing details on Aldebaran's occultation by the moon.

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Dec 27

2015

by Johannes Stübler

On December 23rd 2015 an interesting detail was captured here at our local public observatory (Kepler Sternwarte Linz/Austria). Herbert Raab (chief of our local association) used an DSLR and our 130mm APO to make a video of the occultation. Due to the fact the RedGiant Aldebaran has an angular diameter of 0,02" (arcseconds)  - which is equal observing a human hair at the distance of 500 meter !!! - the star did not suddenly disappear. The Moon's speed was about 0,55" per second which is equal ~0,01" between single videoframes - so we could capture the "fading-out" of the star.  Usually an occultation of a star by the moon, seen by the naked eye, looks like turning off the light promptly. Even this was here - with the naked eye!  ..... but, here it's proven, modern techniques can show more :-)

The full video can be seen here:  Occultation of Aldebaran by the Moon 

Unfortunately we could not observe the end of the occultation ... more and more clouds prevented the observation.

Johannes Stübler