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The Sky This Week, 2010 April 27 - May 4

Mirth & Merry Making for May Day
Moon_Merc_Venus_100415small.jpg
 Venus, Mercury, and a 36-hour old crescent Moon
Imaged from Alexandria, Virginia, USA on 2010 April 15 with a Canon PowerShot S2IS digital camera, 10s. exposure @f/4, ISO 50, 3.5X optical zoon.

The Moon spends the week waning in the morning sky as she wends her way through the rising constellations of summer. Last Quarter occurs on May 6th at 12:15 am Eastern Daylight Time. During the week Luna hugs the southern reaches of the sky, flanking the ruddy star Antares, heart of Scorpius, the Scorpion, on the mornings of April 30th and May 1st. On the morning of the 3rd she may be found above the "Milk Dipper" asterism among the stars of Sagittarius. She then passes into the star-poor reaches of the autumnal constellations, now rising as twilight begins to herald the sunrise.

May 1st is a special day in ancient skywatchers’ calendars. This day can either be regarded as the mid-point of spring or the beginning of summer, depending on which traditions you subscribe to. The day is widely celebrated as "May Day", which in modern times is the "International Workers’ Holiday". In earlier times it was a day of feasting and merriment derived from a Celtic fertility rite known as Beltaine. It was the time when herds of farm animals were turned out to pasture for the "Month of Three Milkings". Great bonfires were lit, May and Morris Dances were performed, and young maidens danced around the May-Pole to ensure successful reproduction in the flocks. In general it was a happy celebration of the year’s longest days, a stark contrast to Samhain, which occurs half a year later at the time we now call Halloween.

Venus is the dazzling object that you are now seeing in the western sky shortly after sunset. Brighter than any other celestial object except the Sun and Moon, Venus is very hard to miss, even in twilight. As the week opens she is placed between the Pleiades star cluster and their half-sisters in mythology, the Hyades. The latter group forms the distinctive "V" shape of the face of Taurus, the Bull, with the orange-tinged star Aldebaran marking one of the Bull’s eyes. Venus quickly passes to a point almost directly above Aldebaran by the end of the week. You’ll probably need binoculars to see the fainter stars of the two clusters, though.

Ruddy mars spends the week drifting eastward at a point about halfway between Pollux, brighter of the Gemini Twins, and Regulus, the heart of Leo, the Lion. Here’s another chance to use your binoculars to scout out another star cluster. Just over four degrees to the west of Mars is the cluster known variously as the Beehive or the Praesepe. On moonless nights from dark sites you can see this cluster as a small nebulous patch with the naked eye, but it really reveals itself when you train binoculars on it. Mars will pull away from the cluster this week as he accelerates toward Saturn, a couple of constellations to the east.

Just over half the distance from Regulus to the rising glow of the blue star Spica is where you’ll find Saturn. The ringed planet is barely inching along among the stars of Virgo, and he is now very well-placed for telescopic perusal. The planet’s famous rings are now tipped just 2.5 degrees to our line-of-sight, but because the Sun shines on them at a higher angle a modest telescope will reveal a dark, slender shadow where the rings cross the planet’s disc.

Giant Jupiter now rises just before the onset of morning twilight, but you should have no trouble finding him in the eastern sky if you’re up before the Sun. It’s still a bit too early to set the telescope on him, but patience will reward us with a fine Jovian show in the late summer and fall.

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