Date:04/05/2008 URL: http://www.thehindu.com/2008/05/04/stories/2008050452131800.htm

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Mars-moon spectacular

Lalithasai

CHENNAI: On May 10, sky-watchers in India, South East Asia, West Asia and Europe will see the moon snap Mars out of sight. Mars will appear to inch up to the edge of the moon, and hang on to it for a few seconds, before suddenly disappearing — only to reappear after an hour.

When a celestial body hides another body despite being situated far apart, the phenomenon is called occultation. Says Dr. P. Iyamperumal, Executive Director, Tamil Nadu Science and Technology Centre, Chennai: “The eye-catching event will happen in complete darkness. The moon will come directly between Mars and the earth. Mars will hide behind the crescent moon after about 7.30 p.m. (IST). In Chennai, for instance, it will happen at 8.05 p.m. It will take about 13 seconds for Mars to go behind the moon. The edge of the planet will touch the edge of the moon and slowly disappear… In Chennai it will reappear by 9.16 p.m. The exact time will depend on the location of the observer.”

The planet playing hide and seek with the moon will be a striking spectacle. A dim light will be produced by sunlight striking the “dark” side of the crescent moon after first being reflected from the earth’s surface, clouds and atmosphere.

According to the Director, at the beginning of the event Mars will be about 45 degrees up on the western horizon. The angular diameter of Mars will be about 5.5 arc seconds. When the moon leaves the planet it will be at a height of 30 degrees on the western horizon.

In Chennai, the B.M. Birla Planetarium, Periyar Science and Technology Centre, has made arrangements for the public to observe the event. Plans are afoot to project the sight on to a screen.

The occultation can be viewed in New Delhi between 19.41 hours and 20.44 hrs, and in Mumbai between 19.46 hrs and 21.02 hrs, according to the executive director.

An occultation of Mars by the moon that was visible in India occurred last on April 14, 2007. India witnessed an occultation of Venus by the moon before dawn on November 10, 2004. An occultation of Saturn was visible from India in 2002.