Occultation of alpha2 Librae (Zubenelgenubi) by the Moon, June 20, 2013

The evening sky facing east in Sydney on June 20 at 5:05 pm AEST showing the waxing Moon just about to cover alpha2 Librae (Zubenelgenubi). (similar views will be seen from other locations at a similar local time eg 5:08 AEST Canberra). The inset shows a telescopic view of the Moon at 5:05 pm AEST, with alpha2 Librae about to go behind the Moon.

The waxing Moon passes in front of the bright alpha2 Librae in the constellation of Libra on the evening of June 20. Alpha2 Librae, which rejoices in the name Zubenelgenubi, is a bright white star readily visible to the unaided eye (magnitude 2.8). The occultation will be seen from eastern Australia and South Australia. Everywhere else will see a nice, close approach. Appearance and disappearance times are shown in the table below.

 With the Moon not far from Full (23 June), this event is really best seen with binoculars or a small telescope (especially for the reappearance of the star on the bright limb of the Moon). If you have a tripod or other stand for your binoculars, it will be much easier to observe. Set up about half an hour before the occultation to watch the star dissapear (so you are not mucking around with equipment at the last moment).