The Sky This Week, 2016 November 15 - 22
|NGC 869 & NGC 884, the Perseus Double Cluster
Imaged from Fishers Island, NY on 2013 April 15
with an Antares Sentinel 80mm (3.1-inch) f/6 refractor
and a Canon EOS Rebel T2i DSLR
The Moon wanes in the late night and early morning sky this week, taking a respite from the "Super Moon" hype that peaked on the 14th. Last Quarter occurs on the 21st at 3:33 am Eastern Standard Time. Luna opens the week among the stars of Taurus, the Bull. She then moves eastward through the bright stars of the Great Winter Circle. By the end of the week you’ll find her in the morning sky, where she will pass just over a degree to the south of the bright star Regulus before dawn on the 21st.
As the Moon moves into the morning sky you now have time in the early evening to explore some of the interesting constellations of the late autumn sky. A few weeks ago we introduced you to Pegasus, or more generally the "Great Square" asterism that makes up the bulk of the constellation. You’ll find it on the meridian just south of the zenith at around 8:30 pm EST this week. If you turn and face northward, you should see the "W" asterism that marks the constellation of Cassiopeia, the Queen. From a dark location you’ll see the Milky Way running through Cassiopeia, and this is one of the most fertile hunting grounds for owners of binoculars and small telescopes. There are dozens of star clusters embedded in the star clouds of the Galaxy here. They will look like knotty globs of light in binoculars, but a good three-inch telescope will reveal their stellar nature. To the east of Cassiopeia you’ll see a bright star embedded in the Milky Way that’s surrounded by a group of fainter stars. This is Mirfak, the lead star in the constellation of Perseus, the Hero. From a dark location the stars scattered around Mirfak are just visible to the naked eye, and they offer the suburban skywatcher a wonderful view in binoculars. This is an actual star cluster, one of the closer ones to us at a distance of a bit over 500 light-years. Between Mirfak and Cassiopeia you’ll find one of the best treasures of the nighttime sky. Visible as a hazy enhancement of the Milky Way from dark skies, it is one of the most rewarding sights for telescopes of any aperture. "It" is actually "them", since what you’re looking at is popularly known as the Perseus Double Cluster. The telescope will reveal a pair of fine galactic clusters that each contain hundreds of stars. Among these stars are some of the brightest known in the Galaxy, with luminosities some 60,000 times that of our Sun. These are thought to be some of the youngest star clusters in the heavens, with an estimated age of a mere 12.5 million years. They are located some 7,500 light years away.
Venus continues to put more distance between herself and the Sun. She is now beginning to creep northward along the ecliptic as she moves into the constellation of Sagittarius. You’ll find her dazzling glow in the southwest in the hours after sunset.
We now bid a fond farewell to Saturn for 2016. The ringed planet is now draped in bright twilight and will pass behind the Sun in early December. He’ll become prominent in the evening sky next year, when his opposition occurs on June 15.
Mars is now embarking on his long transit through the faint autumnal constellations. This week he transits the constellation of Capricornus, the Sea-goat. This constellation has a sway-backed triangular shape, but with its brightest stars coming in at third magnitude it is only clearly visible from dark skies. Mars far outshines its brightest rivals in this part of the sky.
Jupiter rises at around 3:30 am and is well-placed for viewing as morning twilight begins to glimmer on the horizon. He will be the brightest object in the eastern sky at this time. He’s now high enough to grab a quick view in the telescope before sunrise, when the air is generally nice and still for viewing detail.