Astroblog: Occultation of Uranus by the Moon

Thursday, June 04, 2015

Occultation of Uranus by the Moon


North-Eastern horizon as seen from Brisbane at 5:00 am AEST, just before Uranus is covered by the Moon (click to embigen).	North-Eastern horizon as seen from Brisbane at 6:23 am AEST, just after Uranus exits from behind the Moon

North-Eastern horizon as seen from Adelaide at 4:15 am ACST, just before Uranus is covered by the Moon.	North-Eastern horizon as seen from Adelaide at 5:30 am ACST, just after Uranus exits from behind the Moon.

North-Eastern horizon as seen from Hobart at 5:00 am AEST, just before Uranus is covered by the Moon.	North-Eastern horizon as seen from Hobart at 6:10 am AEST, just after Uranus exits from behind the Moon.

On the morning of Friday 12 June Uranus is occulted by the Moon as seen from southern Australia (basically anywhere south of Townsville).

For western Australia the Moon will be low to the horizon (or below it) when Uranus goes behind the Moon, but the sight of Uranus popping up from the Earth-lit dark side of the Moon will be rather nice from these places.

In the more north-eastern sites the Uranus goes behind the bright edge of the Moon when it is dark, but exits in twilight. For Brisbane the occultation starts high in the sky, but Uranus appears from behind the Moon about 15 minutes from sunrise, and reappearance may only be visible in decent telescopes.

South Australia, Victoria and Tasmania will have good views of ingress and exit.

The Moon is a very obvious signpost for where to look low in the east. Uranus will be the brightest object near the Moon, but will only be visible in binoculars or a small telescope.

The occultation occurs in the early morning with the Moon just above the horizon at the start (except in Perth), when Uranus disappears behind the bright edge of the crescent. The Moon is easily visible and a ready signpost to Uranus.

It is advisable to set up and practise on the Moon a day or so before the event, so you are familiar with your telescope set-up. Set up at least half an hour ahead of time so that you can be sure everything is working well and you can watch the entire event comfortably (trying to focus your telescope on Uranus moments before the occultation will cause a lot of unnecessary stress). Uranus will be clearly visible in a telescope or binoculars near the Moon. See the diagrams above for the appearance of Uranus near the Moon. Uranus will be a bright dot in all but moderately powerful telescopes, where it will appear as a small disk.

Place	Moon rise	Disappears Bright Limb	Reappears Dark Limb	Astronomical Twilight
Adelaide ACST	2:20	4:19	5:27	5:50
Brisbane AEST	1:45	5:06	6:22	5:12
Canberra AEST	2:06	4:59	6:13	5:38
Darwin ACST	1:44	-	-	5:49
Hobart AEST	2:20	5:01	6:07	5:57
Melbourne AEST	2:25	4:55	6:06	5:58
Perth AWST	2:23	-	3:28	5:47
Sydney AEST	1:56	5:01	6:17	5:28