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The Sky This Week, 2014 April 1 - 8

Signs of summer in the night...

 The last of winter's stars

Paris, Virginia, 2014 March 27

The Moon returns to the evening sky this week, springing upward from the western horizon as she waxes through her crescent phases. First Quarter occurs on the 7th at 4:31 am Eastern daylight Time. This is a good week to explore our nearest neighbor as she goes through her crescent phases. Her high declination gives her a lofty perch on successive nights, showing her to good advantage. Look for her just four degrees west of the bright star Aldebaran on the evening of the 3rd. On the 6th she passes just over five degrees south of bright Jupiter.

As April opens we can still find the bright stars of the Great Winter Circle lingering in the west and southwestern skies as dusk deepens to darkness. This is the last month we’ll have to see these bright patterns in a dark evening sky until late this fall. The way this past winter has been, I, for one, won’t be sad to see them go. As much as I enjoy looking at Orion striding over a cold, snowy landscape, it’s time for him and his friends to give way to stars of warmer times. Orion’s most striking naked-eye feature to me has always been the ruddy glowing coal of the star Betelgeuse, which marks the Hunter’s shoulder. Betelgeuse now sets just before midnight, but if you look to the southeastern sky at this time you’ll see another glowing coal rising out of the haze. This is the star Antares, brightest star in the summer constellation of Scorpius. Both Betelgeuse and Antares are "red supergiants", stars which are near the end of their evolutionary tracks. They are swollen hulks of massive stars whose tenuous outer envelopes would gobble up the planets in our solar system out to the orbit of Mars. They have enormous but relatively cool surfaces, hence their distinct ruddy hue. In mythology the lowly scorpion was the one creature that Orion couldn’t overcome, so the gods placed the two adversaries on opposite sides of the sky. There are a number of other similarities between the stars of these two constellations, but we’ll save those for another time.

You still have a few hours of darkness to enjoy the view of Jupiter in the evening sky. The giant planet becomes visible near the meridian almost as soon as the Sun sets and dominates the western sky once it’s fully dark. You’ll have a good view of him until the wee hours with the naked eye, but if you’re using a telescope to peruse him he’ll start to settle into more turbulent air by midnight. His disc has diminished by almost 10 arcseconds in apparent diameter since opposition back in January, but he still offers the most generous surface to look at of all the planets. His atmosphere remains in constant turmoil; on the last night of March I spotted a large feature that wasn’t there a week ago. It must be a ferocious storm, because it is about as long as the circumference of the Earth!

Mars is quickly moving into the evening sky and is currently at his best and brightest for the current apparition. Opposition occurs on the 8th when the red planet rises at sunset and sets at sunrise. At this time his telescopic disc will be just over 15 arcseconds in apparent diameter, less than half that of Jupiter. Nonetheless, careful scrutiny of Mars through a telescope will reveal tantalizing bits of detail to the patient observer. The planet’s shrinking north polar cap and transient clouds over its high volcanic peaks have been very prominent of late.

Saturn will reach opposition in early May and is following on Mars’ heels. Even though he’s quite low in the sky his mysterious rings are tipped very favorably in our direction. Almost any telescope should show them. The ringed planet is a fine reward for observers who spend a few hours trying to tease detail from the ruddy disc of Mars.

Venus greets early risers in the southeast during morning twilight. There is no mistaking this dazzling world, but you’ll need a clear horizon to get a good look at her.

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