Thursday, October 04, 2012

Occultation/Graze of Jupiter by the Moon Saturday October 6, 2012

Morning sky on Saturday October 6 looking north as seen from Adelaide at 5:00 am local time in South Australia. The Moon will graze Jupiter in two hours time. 

Jupiter is below the Hyades and makes a long triangle with the red stars Betelgeuse and Aldebaran. Similar views will be seen elsewhere at the equivalent local time (click to embiggen).

On the morning of Saturday October 6th Jupiter is either grazed or occulted by the Moon as seen from the South-eastern states of Australia. Elsewhere in Australia the Moon is very close to Jupiter and well worth watching.

The occultation/grazes occurs in daylight (except in Perth, where the occultation starts in the twilight, times given below), but don't dispair, the event can still be viewed in telescopes and binoculars if care is used to not accidentally point them at the Sun. Jupiter will appear pale and washed out in binoculars and telescopes (as will the Moon), but you can still see them reasonably well.

If you start following Jupiter and the Moon in the pre-dawn twilight, when they are both easy to see, it will make your task much easier (and the approach of Jupiter to the Moon is quite spectacular, even in binoculars). At mid graze/occulation, the Moon will be quite low to the horizon (especially in Hobart Launceston), so if you are using a telescope, make sure it has a clear horizon and can point down reasonably well.

Make sure the Sun is hidden behind something solid like a building or a wall when you are looking at Jupiter and the Moon after the sun has risen, not trees or your hand. Exposing your eyes directly to the glare of the Sun can be very dangerous and you could potentially lose your sight. This is doubly true if you are using binoculars or a telescope.

AdelaideGraze7:31 ACST
BrisbaneClose Approach8:30 AEST
CanberraGraze Nearby8:11 AEST
HobartOccultation7:42-8:22 AEST
LauncestonOccultation7:45-8:25 AEST
MelbourneGraze8:05 AEST
PerthOccultation4:52-5:50 AWST
SydneyClose Approach8:15 AEST

Moon as seen from Adelaide at 7:31 am ACST at mid graze, the Moon is low above the north-west horizon.Telescopic View of Moon and Jupiter at Mid Graze as seen from Adelaide. Similar views will be seen from Melbourne. Canberra Jupiter just misses the Moon.

Moon as seen from Hobart at 7:42 am AEST at the start of the occultation, the Moon is low above the north-west horizon.Telescopic View of Moon and Jupiter as Jupiter enters occultation as seen from Hobart.

The sight of the Moon skimming just behind the Moons curve is pretty amazing, so it's well worth making an effort for this.

This is also an excellent time to try and see Jupiter in the daylight, using the Moon as your guide.