Sky Talk May 2011: Predawn Planetary Conclave

Those of you who don’t mind rising early in the morning will have a special treat this month as you look toward the eastern sky before dawn. There you’ll find a grouping of four of the major planets — and a spectacular close approach of the two brightest ones!

For a week or so around the morning of May 11th, radiant Venus and slightly fainter Jupiter will grace the eastern sky about an hour before sunrise. On that date itself the two planets will be just half a degree — or a Moon’s width — apart, creating a stunning sight even with the naked-eye. In binoculars the view both then and for several days on either side of the 11th will be truly spectacular! Watch these worlds slowly close together and then move apart over a period of days. For those fortunate enough to own a low-power, wide-field telescope like the Edmund Astroscan Plus, not only will the view be even more of a spectacle with brighter images than binoculars can deliver but at magnifications of just 20x to 30x the little disks of both planets will be visible. (Due to atmospheric turbulence this close to the horizon, don’t expect the images to be sharp. But both objects will be definitely non-stellar.)

Two additional but much less bright and obvious planets lie nearby around this time. As seen during the interval 60 minutes to 30 minutes before sunrise, elusive Mercury will appear between 1.5 and 2 degrees to the lower right of Venus and ruddy Mars will be positioned closer to the horizon some 5 degrees to the east of Jupiter. Seeing them with the unaided eye in the brightening twilight will be a challenge but both should show up well in binoculars. In wide-angle glasses having at least a 6-degree field, it will actually be possible to see all four planets in the same field of view when bunched closest together! In a telescope, Venus and Jupiter can be followed all the way up to (and beyond) sunrise itself. But extreme caution is needed here so that the scope isn’t accidentally turned onto the blazing Sun. As an aside, on the morning of May 1st, a lovely crescent Moon will grace the sky just above Jupiter. And by the 29th, one orbital revolution of the Earth later, the crescent Moon will again be near Jupiter. The sky is indeed a stage on which celestial drama continuously plays out to the delight of skywatchers!

In closing, we must not neglect to mention that magnificent golden Saturn is well placed for viewing during the evening in May. Look for it halfway up the southern sky, to the upper right of the bright bluish star Spica. Note that Saturn doesn’t twinkle — but Spica certainly does! For the reason why, see the Sky Talk column for June 2008. (All the previous installments are archived on the Edmund Scientifics web blog.)

–James Mullaney
Former assistant editor at Sky & Telescope magazine and author of eight books on stargazing.