Light pollution is a killer for seeing these objects with your naked eye. To find out how dark your location is, use the Google Map Overlay of light pollution. If you are in a blue, gray or black area then you should have dark enough skies. You may still be able to see some of these objects in a green location. If you aren’t in a dark sky location you may still be able to see these objects with a pair of binoculars or telescope.
You can find help locating the night sky objects listed below by using one of the free sky charts at Skymaps.com (scroll down to Northern Hemisphere Edition and click on the PDF for July 2011). The map shows what is in the sky in July at 10 pm (for early July; 10 pm for late July).
If you are not familiar with what you see in the night sky, this is a great opportunity to step outside, look up, and begin learning the constellations. The sky is beautiful and filled with many treasures just waiting for you to discover them. Once you have looked for these objects go through the list again if you have a pair of binoculars handy, the views get better!
A few new items added to the list to view this month, along with some of the previously mentioned ones from June.
The Asteroid Vesta is visible to the naked eye in the constellation of Capricornus. The Dawn Space Craft is on it’s way to Vesta as I type this, and should start it’s orbit around Vesta on July 16, 2011 for one year. You may not see Vesta moving across the sky, but if you track it all month long you will notice it’s change of position in the sky.
Although it may be easier to view later in the night around midnight or later – The Andromeda Galaxy cataloged as M31 is visible to the naked eye in the northeast. The Andromeda Galaxy is the closest galaxy to the Milky Way lying about 2.5 million light-years away. If in a dark enough location the light produced by this galaxy is roughly the diameter of 5 moons in our sky.
The Double Cluster, cataloged as NGC 869 and NGC 884 is a beautiful cluster that shows quite a group of stars with the naked eye. M34, which you may need to wait until around 11pm for it to be high enough to see is nearly a moon-diameter wide and is a fairly easy to see open cluster.
Messier Object 7 (M7) is an open star cluster near the stinger of Scorpius is a small, hazy patch known since antiquity. Visible enough that the Greek astronomer Ptolemy cataloged it. M6 an open star cluster is nearby to the north of M7 and is a little smaller and fainter. M6 is also known as the Butterfly Cluster.
M8 is an open star cluster and nebula complex, also known as the Lagoon Nebula . Visible to the naked eye as a small hazy patch. Bright enough that it is visible even in suburbia. It may look small with the naked eye, but it is actually quite large nearly two moon diameters across. I’m not sure if any of the other objects are visible to the naked eye, although Sagittarius is a beautiful sight as it lays in the Milky Way.
The Great Rift is a non-luminous dust cloud that can be seen splitting the Milky Way in two separate streams. It stretches from Aquila to the constellation Cygnus although it is more prominent in the constellation Aquila.
Messier Object 13 (known as M13) is a globular cluster. It will have a small hazy glow to it.
North America Nebula (NGC7000) – The unaided eye sees only a wedge-shaped star-cloud which may be quite dim, or not visible at all. In dark skies it should pop out a bit. Located near the star Deneb. M39 an open cluster patch of stars northeast of the star Deneb. The Northern Coalsack spans across the sky between the stars Deneb, Sadir, and Gienah in the northeastern portion of Cygnus. If you don’t know which stars of Sadir and Gienah just find Deneb with the map and look to the east northeast.
Mizar and Alcor is a double star in the handle of the Big Dipper. Was once used as a test of good eyesight before glasses. Mizar resolves into a beautiful blue-white and greenish white binary (double star system). They are labeled on the map I linked to above.
Photo: Andromeda Galaxy in a Wikipedia photo taken with an H-Alpha filter which helps filter out artificial light and skyglow; Below, Screen capture from the astronomy freeware Stellarium showing where Vesta is located in Capricornus on July 9.
Michael Rector is an amateur astronomer with his own blog, Adirondack Astronomy.