Tuesday, February 07, 2017
The Moon Occults Regulus (11 February-12 February 2017)
On the late evening of Saturday 11 February the bright star Regulus is occulted by the Moon as seen from the most of Australia. This is the first of two occultations of Regulus, the brightest star in the constellation of Leo the lion, this year. The Moon is a very obvious signpost for where to look and Regulus will be the brightest object near the Moon. Start watching about half an hour before hand to get set up and become familiar with the sky. Although this event is easily seen with the unaided eye, given the brightness of the Moon the occultation is best seen in a small telescope or binoculars.
Regulus will appear to "wink out" as it goes behind the bright limb of the Moon, reappearance will be harder to see as you have to be looking just at the right moment. The "Dark" limb of the Moon isn't particularly dark as the Moon is full.
The occultation occurs in the late evening 11th/just past midnight into the 12th (see table below), the Moon will be reasonably high above the north-eastern horizon. The Moon is easily visible and a ready signpost to Regulus.
If using a telescope, 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 moments before the occultation will cause a lot of unnecessary stress). Regulus will be clearly visible with the unaided eye, binoculars or in a telescope near the Moon before the occultataion. Here's some images from an occultation of Spica back in 2013, so you know what to expect.
|Place||Disappears Bright Limb||Reappears Dark Limb|
|Adelaide ACDST||23:43||01:05 (12th)|
|Brisbane AEST||23:41||00:50 (12th)|
|Canberra AEDST||00:34 (12th)||01:50 (12th)|
|Darwin ACST||22:40 (graze)||-|
|Hobart AEDST||00:37 (12th)||01:58(12th)|
|Melbourne AEDST||00:28 (12th)||01:51(12th)|
|Sydney AEDST||00:37 (12th)||01:58 (12th)|