Abstract

The Occultation Video Revolution - Opportunities for Amateur-Professional Partnership in Education and Public Outreach

David Dunham

Preisgünstige Videokameras bieten professionelle Möglichkeiten zur exakten Messung von Sternbedeckungen. Sie verbinden die amateur-professionelle sowie die populäre Astronomie und eignen sich hervorragend für den pädagogischen Unterricht.

Occultations of bright stars are easily-seen phenomena, videorecordings of which can educate high school and college students, and even the general public, about motions in the sky and the discipline needed to make simple but useful and time-critical observations.

About once a month, a star is occulted that is bright enough to be recorded directly by most camcorders - no telescope is needed. If a timed recording of a selected direct satellite or local TV broadcast is made, anyone in the region with a camcorder can record these events, and the tapes can be processed to determine event times to 0.03 second, providing a measurement of the star relative to the Moon's edge of 30m or less, more accurate than the best laser rangings by the Clementine spacecraft.

Ultimately, since the lunar orbit is well-known from analysis of lunar laser ranging and accurate stellar data are available from Hipparcos, these observations can be used to improve our knowledge of the lunar profile. This helps our analysis of total and annular solar eclipse Baily's bead timings that we use to measure small variations of the solar diameter that might be significant for global climate studies.

In addition, amateur astronomers can now quite easily videorecord lunar occultations and grazes, and the brighter asteroidal occultations, for a small fraction of the cost of most telescopes. A $90 camera can record occultations of 10th-mag. stars with optimized 6-inch telescopes, and 9th-mag. stars with common 8-inch Schmidt-Cassegrain telescopes.

For more information, visit the Web site of the International Occultation Timing Association at http://www.lunar-occultations.com/iota.

Dr. David Dunham, President of the International Occultation Timing Association & Johns Hopkins Univ. Applied Physics Lab.
Address: 7006 Megan Ln., Greenbelt, MD 20770-3012, U.S.A. E-Mail: dunham@erols.com Internet: http://iota.jhuapl.edu
Telephone: +1 301 474 4722 Fax: +1 240 228 1093

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