Tonight's the night for best view of Jupiter in a decade

ABU DHABI // The Emirates Mobile Observatory is giving amateur astronomers the chance to watch closely as Jupiter appears at its biggest and brightest in a decade. The last time the largest planet in the solar system was this close to earth was in 1999. The mobile observatory will set up its telescopic equipment in Khalidiya Public Garden, by the Corniche, from 8pm to midnight so residents can get a better look. Nazar Sallam, president of Emirates Mobile Observatory and a member of the Arab Astronomical Union, will be on hand to explain the finer scientific points of the occasion to those who turn up.

He said the event occurs when the Sun, Earth and Jupiter are aligned with each other. "All the atmospheric features of Jupiter could be seen through a telescope," he added. Jupiter's relative proximity will allow its turbulent weather patterns to be seen clearly with a telescope tonight. The clouds near its poles move so quickly they go all the way round the planet once every 10 to 15 minutes. "Children will get a chance to live the same experience Galileo lived 400 years ago when he saw Jupiter for the first time through a telescope."

While the size of Jupiter as seen from Earth was 46 arc seconds - an arc second is one 3,600th of a degree - last month, tonight it can be seen at approximately 49 arc seconds. The planet will be around 604 million kilometres from Earth, compared with the 670 or 700 million kilometres that is the closest point for most of its orbit. The Earth is about 150 million kilometres from the sun. Jupiter will appear brightest when it reaches its maximum altitude in the zenith at midnight - the time when the three celestial bodies are in direct alignment.

Mr Sallam stressed that people should use a telescope to see the difference. "Otherwise it will appear like a shiny spot," he said. [e-mail]