Although occultations can occur in a variety of ways, the heavenly body most often involved is our moon which inevitably
will occult (or eclipse) background stars, other planets as well as asteroids. The study of occultations is important, for
example, for the study of the moon's limb and its profile thanks to the grazing of lunar features such as mountains.
What is perhaps more interesting but not as frequent is occultations involving the moon and one of the planets. Typically
the planets involved are Venus, Mars, Jupiter and Saturn. Due to the great magnitude difference between the moon (any
phase) and any of these planets, the photography of these events can be challenging.
Without doubt, the most stunning example of the moon occulting another body is that involving the sun which, of course,
leads to a solar eclipse. This special example of an occultation is available
elsewhere on this site.
Note: The mid-day sun was less than 25° to the east of both the moon and Venus. Setting
circles were calibrated on the filtered sun (RA: 03h 54m 22s Dec: 20° 18' 23") and used thereafter to locate and image
the occultation of Venus (RA: 05h 41m 37s Dec: 26° 44' 34"). Venus was characterized with an apparent diameter of 49.80
arc-seconds, a magnitude of -4.4 and a phase of 10.0% whereas the waxing 2-day old crescent moon was at
magnitude -6.4 and with a phase of only 4.7%.
Body: Venus Mean Distance (A.U.): 0.723 Equatorial Diam (km): 12,104 Mass: 0.82 x Earth Volume: 0.86 x Earth Orbital Period: 224.701 days Number of Moons: 0 Orbital Eccentricity: 0.007 Orbital Inclination: 3.4° Albedo: 0.65 |
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Date: May 21, 2004 14:35:00 - 14:37:15 UT+3 Location: Athens, Greece Equipment: Celestron 14" SCT Losmandy G-11 GEM Canon EOS 300d Baader IR-Cut Filter (1.25") Exposures: 7 x 1/3200 sec ISO 800 RAW Image Format 3072 x 2048 Image Size Manual Mode Software: Canon FileViewer V1.3.2 Photoshop V6 Processing: RAW to TIFF (16-bit) Conv Levels & Curves Masks & Layers Resampling JPG Compression |