View Full Version : Jupiter at 'Opposition'

2006-May-04, 02:51 PM
Jupiter will be at 'Opposition' , and the closest to the Earth this year, at 14:36 UT, 4 May.
The planet will be due South at local midnight (At about 01:20 - 01:30, allowing for UK Summer Time).

One thing to watch out for during opposition are the rare eclipses of Jupiter's Galilean Moons, Io, Europa, & Ganymede (Callisto does not undergo eclipses this year, because of the tilt of the satellite orbits viewed from the Earth). The other three will still undergo eclipses, but the shadow of Jupiter falls directly behind the planet, because the Earth lies directly between the Sun and Jupiter, and the eclipse event will be hidden by the disk of Jupiter during the eclipse.


However, there is a very rare phenomena that can sometimes be seen.
On May 4/5, when Europa enters eclipse on one side of the planet, it will re-emerges from eclipse on the other side.
This is because eclipse-event occurs exactly at the time of opposition, and because of the satellites orbital tilt..


As the Europa eclipse event occurs from 23:06 to 01:39 UT on May 5th,
Europa will pass South of the centre of Jupiter's disk.
And because the moons orbit is tilted away from the Earth and the Sun, the moon will enter Jupiter's shadow on one side of the disc, and emerge from the shadow on the other side, only a few hours later.

However, the timing is not exact, and both of these events occur close to the edge of Jupiter's disc;
a large telescopes and good viewing conditions are needed.

2006-May-05, 01:20 PM
Blob, your comments and diagrams are much appreciated. Thanks for the explanation. :)