Skip to main content

The Sky This Month - August 2011

Posted in
Written by Gary Boyle, Ottawa on
Post Date: 
Tue, 2011/08/02

The Glory Of The Night

August is a busy time for campsites and cottages as city dwellers plan their vacation. It is that special time when the family or a group of friends plan their meals, pack the car and drive to the wilderness. If weather is on your side, the outdoor experience can be a thing of beauty. Between the sweet smell of fresh air, the peace and quiet along with first hand witnessing nature in all its glory, camping can be a memorable experience. Of course physical activities such as hiking, swimming or even fishing are enjoyed during daylight hours. However, when the Sun’s last photons disappear behind the mountains and out of view, the night sky begins to change.

As minutes tick by, the pastels of the sky transform before our eyes as stars come out to play. Like popcorn – they appear one by one, first the brighter ones reveal themselves then gradually fainter and fainter. On a moonless night, words cannot describe the blanket of stars above you. To add the finishing touch to our celestial portrait, the veil of our Milky Way Galaxy arcs high and bright. This misty band stretching from Cassiopeia the Queen in the north east down to Sagittarius and Scorpius in the south, is literally the glow of millions of distant stars. You are simply looking along the galactic plane - at its thickest concentration.

 

 

Sweeping the sky with binoculars is an excellent way to take in beauty of the night. Your trusty bino and keen eyesight will help you locate areas of dark nebulae in Sagittarius, Scorpius and Ophiuchus. These ghostly dark objects were photographed and catalogued by E. E. Barnard. You do need a clear southern view and no light sources, not even campfires in the area. Complete darkness is essential but the rewards are grand.

To truly enjoy any celestial object up close, a telescope is crucial. A vast collection of objects are found within about fifteen degrees from the southern horizon. Like shad flies around a street light, a good percentage of the 157 known globular clusters reside around our galaxy’s nucleus. To add to the menu of objects, there is an assortment of emission nebulae – aka stellar nurseries where stars are slowly developing. M8 – The Trifid Nebula.

From the Lagoon, keep travelling up the Milky Way to M16 dubbed the Eagle Nebula. This was one of the Hubble Space Telescope’s first targets to image. Its close up view of the heart of the nebula has been renamed the Pillars of Life. The Eagle registers at magnitude 6.4 and reside some 7,200 light years from us. The Eagle is sizably smaller than the Lagoon but has a decent size of one quarter that of the full moon in the sky. So again, not a difficult item for locate from a dark site.

One of the most striking globular cluster in the area is M22. First move to the top of our teapot and travel a full moon’s width to the north east. The cluster is one of the closest globular to us. Its distance is some 10,400 light years away and 97 lights wide. Astronomers estimate the population to be around to 100,000 mark with 32 known variable stars residing in it. Due to the high volume of stars in the galactic nebleus, no galaxies can be seen in this area. Aside from the large number of open and globular clusters, planetary nebulae seem to dot the nucleus of the galaxy.

The closest and largest open cluster to us is M7. With a distance of only 800 light years, this magnitude 3.3 jewel spans the width a couple of full moons in the sky. I once observed the reflection of M7 with binoculars off a very calm lake. The water was as still as glass and I was rewarded with an impressive sight.

Our solar system is now playing host to a cosmic visitor. Comet C/2009 P1 Garradd is presently in the constellation Pegasus at magnitude 8.8 but will continue to brighten till it reaches its predicted brightest of magnitude 5.8 during the last three weeks of February 2012. Comet Garradd makes a close approach to the globular cluster M15 on August 2. We have a great opportunity to follow this comet over several months. Come February – Comet T1-2006 Levi will also be a very interesting target to observe and image.

Mars in now visible in the eastern sky before dawn breaks. Between August 6 and 7, follow the red planet as it scoots under the wonderful open cluster M35 in Gemini. With a close approach of only 25 arc minutes, this will make a great photo opportunity. The next weekend will mark the peak of the annual Perseid meteor shower. This year the shower peaks at 2 a.m. on the morning of the 13th with an estimated rate of 90 meteors seen per hour. But the bad news is the full Sturgeon moon will reduce that number by about half.

Jupiter proudly rises at midnight local time and will become stationary at the end of the month. From the 30th on, the king of planets begins to move westward (retrograde) to its October 28th opposition or the shortest distance between Earth and Jupiter. With Jupiter resting higher on the ecliptic, astrophotographers will have a little less atmosphere to struggle with. As for Saturn, we must say goodbye as this is your last chance to catch a glimpse of the majestic rings before the planet is lost in the solar glare. It will return to our morning skies around mid November.

Until next month, clear skies everyone.

Gary Boyle