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The Sky This Week, 2015 January 13 - 20

All of the planets and a comet to boot!
Lovejoy_150111_0320_01small.jpg
Comet C/2014 Q2 (Lovejoy), 2015 JAN 11, centered on 03:20 UT
Imaged from near Mount Vernon, VA
80mm (3.1-inch) f/6 Antares Sentinel refractor on iOptron Cube Pro mount,
Canon EOS Rebel T2i DSLR

The Moon wanes through her crescent phases this week, and is best seen in the morning sky as twilight begins to brighten the eastern horizon.  New Moon occurs on the 20th at 8:14 am Eastern Standard Time.  Luna has a close encounter with Saturn on the morning of the 18th when she passes just a degree north of the ringed planet.  This should be a treat for viewing in binoculars since the conjunction takes place near the bright stars that form the “head” of Scorpius, the Scorpion.

As we mentioned last week, Venus and Mercury are closely paired in the southwestern sky during early evening twilight.  If you haven’t had a chance to see them you should make the effort to do so on the next clear evening.  As the week opens they are still around one degree apart, with Mercury just to the right of and slightly below Venus.  Both planets should be easy to spy with the naked eye by around 5:45 pm.  Mercury reaches his greatest elongation from the Sun on the afternoon of the 14th; after that date his motion against the stars will slow dramatically and he’ll begin to fade.  You can still use Venus to find him, but the dazzling planet’s steady eastward pace will put some five degrees of sky between them by the end of the week.  In addition, Mercury will begin a rapid fade as he begins to fall back toward the Sun, dimming by a full magnitude by the 19th.

While I was outside admiring the Venus and Mercury show last Saturday I noticed Mars pop out of the fading twilight glow some twenty degrees above the brighter planet duo.  Mars pales in comparison to dazzling Venus, but he is now moving through a very sparse starfield and is the only relatively bright object in the area.  Once the sky has turned a deep blue his ruddy color becomes apparent.  Mars continues to keep apace of the Earth as the two objects whirl in their respective orbits, and he will set at the same time, 8:13 pm, for the next several weeks.  However, he is gradually losing the footrace between Venus and the Sun to overtake him.  This week Venus trims some three degrees in their separation, and by week’s end that gap between them closes to about 15 degrees.  Venus will pass the red planet in another month.

The big story this week is the continuing fine showing by Comet C/2014 Q2 (Lovejoy), which is now marching northward through the stars of Taurus, the Bull.  It is currently about 4th magnitude, so it won’t dazzle us urban stargazers in the same way that Comet Hale-Bopp did back in 1997, but it is still an easy target to track down.  As the week opens the comet lies about 15 degrees west of the bright star Aldebaran in Taurus, and by the weekend it will drift about 10 degrees to the west of the Pleiades star cluster.  The finder chart that we posted last week may still be found here.  I’ve been able to see it consistently in binoculars from my light-polluted yard in the DC suburbs, and last Saturday I ventured just south of the urban sprawl to look for it from near George Washington’s Mount Vernon estate.  From there the sky was sufficiently dark to show the comet as a “hazy star” to my unaided eye, and through my binoculars it was a round fuzzy patch of light about the same apparent diameter as the full Moon.  Through my three-inch telescope I could see a bright, star-like nucleus surrounded by a faintly greenish cloud of haze.  Colleagues who live under darker skies have reported seeing a tail spanning several degrees in their binoculars.  While I couldn’t see the tail by eye, it was easy to pick out in photographs.  Comet Lovejoy is probably at its peak brightness by now, but it should remain a nice binocular target for several more weeks as it drifts toward the easternmost stars in Andromeda.

Jupiter is fast approaching opposition in early February and he is now well-placed in the late evening and overnight hours for telescopic viewing.  Some 405 years ago Galileo turned his primitive telescope toward the planet’s jolly glow and found four star-like objects that accompanied the planet as it moved against the background stars.  Although he was not the first person to see them, he was the first to publish his observations of them, so the four brightest moons in Jupiter’s stable of 67 known satellites are known as The Galileans.  Watching the nightly changes in these four worlds was an endless source of fascination to me as a youngster.  Today modest amateur telescopes can follow their comings and goings in detail, and this year is a particularly good one to do so.  During their orbits the moons sometimes pass between the Sun and their master, casting their shadows on his cloud-tops below.  On the night of the 16th at around 11:30 pm EST you’ll have a chance to see two moons casting their shadows on the planet at once. 

Saturn graces the southeastern sky as morning twilight gathers.  He is slowly drifting eastward near the second-magnitude star Graffias, northernmost of the three stars that delineate the “head” of the Scorpion.  He gets a visit from the waning Moon on the morning of the 16th, which would be a great time for a quick peek at both objects through the telescope.  As majestic as Saturn is, when viewed in the same context as our Moon it suddenly becomes very apparent how far away this giant world really is.

 

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