欧洲南方天文台将网上直播水星凌日
Planet Mercury Passes in Front of the Solar Disk
A solar mini-eclipse! On May 7, 2003, Mercury, the innermost planet in the solar system, will pass in front of the Sun and produce a solar eclipse. But this event will hardly be noticed. Mercury's small disk will indeed barely be bigger than the point of a pencil. Even the smallest sunspots on the solar surface are as big as the Earth and measure 10,000 km or more in diameter, while Mercury's equatorial diameter is only 4878 km.
Bathed in intense sunlight, this small, hot planet moves around the Sun in an elliptical orbit at a mean distance of only 58 million km, much closer to the Sun than other inner planet, Venus (108 million km) and the Earth (150 million km).
The disk of Mercury is very small and will be very difficult to see. A powerful telescope is needed to observe this event and to show clearly how Mercury moves across the solar disk. The disk of Mercury is indeed only 13 arcseconds across (while the solar disk measures about 1800 arcseconds). This corresponds to the size of a 1 EURO coin located at the top of the Eiffel Tower as seen from the ground. Therefore, Mercury will only block 1/20,000th of the Sun's light.
Live images on the web
On this special occasion and in order to provide for everybody the chance to watch this event, the European Southern Observatory (ESO) and the European Association for Astronomy Education (EAAE), together with the Institut de Mécanique Céleste et de Calcul des Éphémérides (IMCCE) and the Observatoire de Paris in France, are providing live images and a running commentary for all interested parties. It is also planned to display images obtained at observatories in the Belgium, the Czech Republic, Hungary, Italy and Spain, and possibly others. The availability will depend on the weather situation in the various places.
European Southern Observatory (ESO)
http://www.eso.org/
European Association for Astronomy Education (EAAE)
http://www.eaae-astro.org/ |
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变色卡
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显身卡