MEDIA RELATIONS OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011
http://www.jpl.nasa.gov FOR IMMEDIATE RELEASE November 15, 1999

WATCH RARE PASSAGE OF MERCURY BEFORE THE SUN ON WEB TODAY

       Today, a rare astronomical phenomenon occurs when Mercury passes directly between the Earth and the Sun for the final time this century. This particular Mercury transit will be of a particular type that has not occurred since the invention of the telescope, and is not expected again at least through the 23rd century.

       An important reminder -- do not attempt to view the Mercury transit with the naked eye or with a telescope or binoculars. The Sun can cause severe eye damage and even blindness. Telescope images of the event from JPL will be fed live on the Internet at http://www.jpl.nasa.gov/mercurytransit today between about 1 to 2:15 p.m. Pacific time (4 to 5:15 Eastern).

       Mercury will graze just inside the Sun's disk for less than an hour between 1:11 p.m. and 2:10 p.m. as seen from Los Angeles.

       Mercury, the planet closest to the Sun, passes Earth every 116 days. But because Mercury's orbit is tilted seven degrees relative to Earth's orbit, only about one in 23 of Mercury's passages between the Sun and Earth results in a transit. The most recent Mercury transits occurred in 1970, 1973, 1986 and 1993, but they were not visible in Los Angeles. After the November 15 transit, the next one visible from Los Angeles will take place on November 8, 2006.

       NASA's Telescopes in Education project, managed by JPL, is sponsoring telescope coverage of the event. JPL is managed for NASA by the California Institute of Technology, Pasadena, Calif.

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11/15/99 JP