The Sky This Week 26 Feb – 4 Mar
The Moon is conspicuous by her absence this week, with New Moon occurring on the 2nd at 9:35 pm Eastern Standard Time. You might just catch a glimpse of her waning crescent in the morning sky, one hour before sunrise on the 27th, as she drifts to the south of bright Venus. Your next chance to see her comes at dusk on the evening of the 3rd, when skywatchers with a flat western horizon and very clear skies may just glimpse a thin sliver of a crescent a few minutes after sunset. At this time the Moon will be just over 20 hours past the new phase, so this would be an extraordinary sighting for a casual observer. Everyone should be able to sight the somewhat fatter crescent at dusk on the 4th.
The moonless hours of the night open with the parade of majestic winter constellations straddling the meridian, led by the bright stars that form the distinctive shape of Orion, the Hunter. Surrounding the striding figure of the Hunter is a magnificent circle of bright stars that is popularly called the Great Winter Circle. To Orion’s left skywatchers in dark locations can see the faint wisps of the winter Milky Way, and sweeping this area with binoculars will reveal a host of star clusters and nebulous patches. As midnight passes, the winter stars dip to the west, and a set of dimmer constellations appear. Easiest to spot is Leo, the Lion, which transits the meridian at this time high in the south. Also nearly overhead is the familiar shape of the Big Dipper, a sure sign of approaching spring. For the amateur astronomer, this part of the sky is a treasure trove of distant galaxies, hundreds of which are visible in small telescopes.
The yellow glow of Saturn becomes apparent in the middle of the Great Winter Circle as the evening twilight deepens. The ringed planet starts the evening off on the meridian, then slides toward the west as the hours pass by. By the week’s end he sets at around midnight, so if you want to have a good look at his glorious rings in steady air, do it early in the evening.
Planet watchers still have plenty of time to enjoy another distant giant, though. Mighty Jupiter dominates the sky for most of the night and will continue to command our attention until early summer. This week we have an extraordinary sequence of mutual events of three of Old Jove’s four bright moons. On the evening of February 28, at 9:57 pm EST, the bright disc of Europa will pass in front of the larger but dimmer moon Callisto. 52 minutes later, the shadow of Io will obscure a part of Callisto in a mutual eclipse. These mutual events are fascinating to watch, and the relative motions between the orbiting moons is apparent in a few minutes’ time.
Although Venus is still the brightest object in the morning sky, the geometry of her position in the sky is making her harder to spot. You have to find her in morning twilight, about 45 minutes before sunrise. If you’re up at around 5:00 am, though look for ruddy Mars among the rising stars of summer.
