Astroblog: Occultation of Jupiter, December 29, 2008

Saturday, December 27, 2008

Occultation of Jupiter, December 29, 2008

The western horizon as seen from Adelaide at 9:00 pm ACDST. Jupiter is behind the Moon.

Jupiter passes behind the Moon on Monday, December 29 2008. Occultations of bright planets, especially Jupiter, are both relatively rare (from any given spot on earth) and quite lovely.

With the Moon being a thin crescent, Mercury right next to it and Venus bright up above, this will be a spectacular occultation.

That's the good news, the bad news is that the occultation occurs soon after Sunset. So for most sites (except Western Australia, where Jupiter goes behind the Moon before Sunset), Jupiter passes behind the Moon when the sky is still bright. This will be near impossible to see with the unaided eye, but will be easily visible in binoculars or a telescope. The exit of Jupiter from behind the bright crescent of the Moon occurs when the sky is reasonably dark (except in WA, where the sky is still quite bright), but when the Moon is quite low to the horizon, so you will need a fairly level, unobstructed horizon to see Jupiter emerge.

Still, while the conditions are quite difficult, the effort is well worth it. The occultation is best from South Eastern Australia, with most of Queensland and northern New South Wales missing out. A table with times for representative cities is here at Southern Skywatch. Strictly speaking, both Sydney and Darwin (shown as misses) see Jupiter go behind the Moon, but at only a few degrees above the horizon under twilight skies this will be very difficult to see. A fuller list of cities and times (in Universal Time), and a diagram of the occultation path is at the International Occultation Timing Site.

So good luck and clear skies for the occultation night!

Labels: Jupiter, Moon, Occultation