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The Sky This Month - August 2006

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Written by Gary Boyle, Ottawa on
Post Date: 
Wed, 2006/08/02

The Glorious Milky Way


If you have never experienced the true portrait of the Milky Way Galaxy unfold before your eyes far off in the countryside on a Moonless night, you are missing one of the grandest moments of your life. I recently had the chance to rent a cottage by the lake with my family for ten days, around new Moon. By 10 p.m. locally, the stars began to show themselves, one by one.

By 10:30 the Milky Way was literally beaming from Sagittarius in the south to Cygnus overhead, continuing through the W of Cassiopeia and beyond. It is difficult to put into words the awe inspiring view of our home galaxy – it is almost a religious experience. With 7 X 35 wide angle binoculars in hand; I immediately attacked the heart of the Galaxy. Sagittarius, looking like a teapot pouring to the right, has a wealth of nebulae, open and globular clusters for your choosing.

If you ever have the chance to find such a dark location far from the city, you should first examine the heart of our home Galaxy. What seems to be misty haze soon becomes evident with binoculars that these are clouds of stars. Scan the region for clumps of faint light and dark matter obscuring some areas. This ghostly veil of light grey is in fact, the glow of millions of distant stars, too far to be resolved as individuals. My knees buckle every time I witness this particular part of celestial landscape. To see so many stars in one field of view and to think each possesses its own story and / or a planetary system. The mere thought can take your breath away.

My first target I picked up naked eye at magnitude 5.8 was the Lagoon Nebula designated as M8. Spanning about two full Moons across, this 5,600 light year (ly) object is a combination of a stellar nursery together with a relatively new open star estimated to be only a million years old. Located north of the Lagoon is the M20, the Trifid Nebula. It is a combination red stellar nursery and a blue reflection nebula.

Moving south to the opposite side of Alnasal (the tip of the teapot’s spout) the 70 to 80 jewels of the bright open cluster M7 greeted me. This magnitude 3.3 cluster resembles the Beehive Cluster – M44 but on a smaller scale. What an impressive show piece to commence the night’s entertainment. On my observing session, the lake was as still as it can get, almost mirror like. I was able to catch the inverse reflections of M7 and M8 along with Sagittarius itself in the calm waters. Adding to the moment, were the occasional echoes of loons breaking the silent of the night. Moving up the stretch of Milky Way you will run into numerous rich stars clusters such as NGC 6546 with M21 and M20 flanking to its right. Stop and examine its detail and overall beauty.

Keep on your northern trek to the mysterious looking Swan Nebula, a.k.a. the Omega Nebula. Both names have the designation as M17 this emission nebula lies some 5,000 ly from us and at sixth magnitude, is just on naked eye limitations. Young hot stars embedded deep inside the nebula, is causing it to glow.

Continue on up to M16 in Serpens. The Eagle Nebula sits a couple thousand ly further from the Swan and is the home of a famous Hubble Telescope image taken in 1995. This fascinating structure is known as the “Pillar of Life” showing star formation in fine detail. The Eagle is another stellar nursery with some of the hottest stars around to the tune of O6 siblings.

As we leave the Teapot, raise your binoculars to Aquila the Eagle and come across an even peppering of hundreds of even magnitude stars. A very nice feature is the single bright foreground star appearing in the centre and is not associated with the grouping Catalogued as M11, it is commonly known as the Wild Duck. This bird’s life is estimated at about 250 million years old and floats around 6,000 ly away. From the low power of binoculars to the intensity of a telescope, this open cluster ranks as one of my favourite top ten open clusters.
 




We now stumble up to the Northern Cross. Cygnus the Swan lies at the zenith locally around midnight. The winged swan appears still framed in flight while casting a silhouette against the starry background. The head of our winged friend, Albireo and is the most beautiful double in the entire sky. It two distinct components appear as a blue and a yellow, however I telescope is required to view this duo in all its glory. You will want to stay at this constellation to catch a few more rich open clusters such as NGC 6834 with some 50 members shining away at magnitude 7.8. While traveling up the Swan’s neck you stumble upon the duo of NGC6871 and 6883.

An extremely large area (4 by 3 full moons) worthy of binoculars is the North American Nebula. Known as NGC 7000 this diffuse nebula located to the left of the star Deneb has an uncanny resemblance to our continent. Flanked to its lower right is the Pelican Nebula. This is another large misty silhouette of the famous beaked bird. Both are on the astrophotographers to-do list.

To cap off the bino session was the Double Cluster in Perseus. At just over 7,700 light years from us and they still hang in Northern skies for the naked eye to catch. Any type of optical aid will show single stars in two small swarms. Speaking of Perseus, the famous Perseid meteor shower is a lengthy shower stretching will rain in all its glory in the night of August 12 and 13. The shower is always slated for more 100 meteors seen per hour for a single observer, however the waning Moon will still be 83 percent lit and will wash out the faint ones thus drastically reducing the numbers. This shower is Earth encounter with the dusty debris from Comet Temple-Tuttle’s tail.

As the days of August tick by, so is your last chance to observe Jupiter. As the month opens, the king of planets keeps high enough to allow detail to be seen. However as the weeks march on, it starts slipping away into the murky horizon.

With binoculars you should be able to recover Neptune. The second to last planet of the solar system appears as an out of focus star and takes on a greenish-blue tone. A telescope will enhance the planet but at 4.5 billion kilometres, the only feature called the Dark Spot is not visible.

Little Mercury will be at its greatest western elongation on August 7th, appearing some 19 degrees up in the morning sky before Sunrise. It will also get fairly close to Venus on August 10th and should make a nice photo opt.

The ringed wonder Saturn is in conjunction (behind the Sun) on August 7 and will be very low in the eastern sky by month’s end and difficult to pick up. However, on the morning of 26th, Saturn will be very close and to the right of brilliant Venus. You might find it that way.

Until next month – clear skies everyone.
Gary Boyle
garyboyle@sympatico.ca