Occultations of Stars by the Moon


This movie of the September 12, 1998 occultation of Aldebaran by the Moon was taken at
UPenn's Flower and Cook Observatory. Click on movie to stop it.

Science from Lunar Occultations

The reason that the star gets brighter just before it disappears is that the light is diffracted around the edge of the almost atmosphereless moon. These graphs of the light from the disappearance and reappearance of other stars being occulted by the Moon are plotted with a solid line showing a modelled Fresnel diffraction curve. Note that each graph covers 1 second of time, increasing from right to left. This data was taken in 1980 on the 60-inch Wyeth Reflector at the Oak Ridge O bservatory and appeared in two 1981 papers on the occultations of stars in the Hyades star cluster by Deane Peterson, and colleagues. Note the occultation of a faint companion to the star on the left after the main star.

Immersion light curve Emersion light curve

For answers to your questions about occultations, contact Doug Mink. If you are interested in observing lunar occultations, check out the International Occultation Timing Association Web site.

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