The Sky This Week, 2012 September 11 - 18

NGC 869 & NGC 884, the "Double Cluster" in Perseus Imaged at Fishers Island, NY on 2012 August 17 80mm f/6 Antares Sentinel refractor & Canon EOS T2i DSLR camera

The Moon moves from the morning to the evening sky this week, with New Moon occurring on the 15th at 10:11 pm Eastern Daylight Time.  Look for Luna close to bright Venus before dawn on the morning f the 12th.  You may still be able to spy her very slim crescent shortly before sunrise on the 14th.  By the end of the week you’ll find her low in the southwestern sky at dusk.

Luna’s absence from the evening sky for most of the week means that it’s still a great time to continue exploring the summer Milky Way with binoculars or a small telescope.  Last week we looked at some of the objects you can see in the mid-evening sky surrounding the stars of the Summer Triangle, Vega, Deneb, and Altair.  With the Moon absent until the wee hours, let’s see what the deep sky has for us as we approach the midnight hour.  At this time you’ll find the Milky Way arching from southwest to northeast, and in the northeast sky you’ll find embedded in the hazy galactic glow the “W” shaped constellation of Cassiopeia, the Queen.  The area between the bright star Deneb and Cassiopeia is packed full of bright knots and condensations which are mostly star clusters.  Several of these lurk in the “W” itself.  Many of these will resolve into stars in the small telescope, others will remain an amorphous patch of stellar fuzz.  However, about halfway between Cassiopeia and the rising “head” of Perseus you’ll encounter two bright knots of stars that are almost intertwined.  Your binoculars should resolve these into two clusters of stars, but the best view of the “Double Cluster” is through a small low-power telescope.  In my 80mm refractor at about 20X magnification both clusters fill the field with hundreds of bright blue and orange-tinted stars, all set on a background of seemingly infinite faint stars from the more remote regions of the galaxy.  Several of the orange stars are quite bright and distinctive with good reason: at their estimated distance of some 7000 light years these stars shine as some of the most energetic beacons in all the sky, blazing with over 100,000 times the luminosity of the Sun!

The evening twilight hours find Mars still slogging along on his eastward trek around the Zodiac.  The red planet is now passing through the stars of the constellation Libra, the Scales, the only “inanimate” sign in the “Circle of Beasts”.  On the 15th Mars passes a scant one degree south of one of Libra’s two bright stars (and a perennial crossword favorite), Zubenelgenubi.  Mars is about four times brighter than the star, and by the end of the week he’ll leave it well behind him as he sets his sights on his ruddy rival, the star Antares in the constellation Scorpius.

By the end of the week Jupiter rises at around 11:00 pm EDT.  The giant planet is now very well-placed for early morning observation, high up in the east at 5:00 am.  This is a great time to give him a look at high magnification, since our atmosphere is usually very quiet and detail is at its best.

Venus rises a bit earlier each morning coming up shortly before 3:30.  She gets a visit from the Moon before dawn on the 12th.  Also on that morning, as well as the 13th and 14th, she passes just south of the “Beehive” star cluster as she slides eastward among the stars of Cancer.

I woke up early this morning to take in the view of Jupiter, the crescent Moon, Venus, and the bright stars of the Great Winter Circle.  It was a morning that was startlingly reminiscent of a similar day eleven years ago.  Seeing this beautiful array of distant worlds in the cool of morning twilight brought a measure of peace and serenity to a day of solemn observance.  The ever-changing sky always reminds me that we are a very small part of a very large universe in which events on our world are just a blip in the time line.  But I will still remember.