July 2010

Tony Martinez

Each month I will describe sights of interest in the night skies of South Carolina. These sights will be broken down into three sections; what you can see with the naked eye, with binoculars, and with a small telescope. The best time to view the night sky is at and around the times when the Moon is not visible, what is known as a New Moon; which will occur this month on July 11th. For July, your best viewing nights will be from July 1st through July 16th. The Star chart below is set for Florence, SC on July 15th at 9 pm.

The Summer Messier Objects:

Remember, if you work your way through the famous Messier List, you will easily learn the night sky. Summer is always a nice time to go out star gazing, although the humidity can sometimes interfere with clear sky viewing. This month I want to take you on a short tour of some Messier Objects of the southern summer sky. Your equipment for this journey: a pair of binoculars, seven to ten power, a lawn chair, beverages, and snacks of your choice. As you look to the south this month, you are looking into the center of our Milky Way galaxy. The fact that we are looking into the center of our galaxy in the summer is why the Milky Way is much brighter in the summer than in the winter when we are looking away from the galactic center. So let’s start our trip by referring to the map of the southern sky shown below.

The first stop is the globular cluster; M22 in Sagittarius. Many say that the globular cluster M13 in Hercules is the best globular cluster of the northern hemisphere, but I vote M22 as the best. This cluster is easy to find with binoculars because it is just to the left of the top star in the “Teapot” asterism in Sagittarius. Although M22 contains more than 70,000 stars, through binoculars, it is just a fuzzy ball, but remember, most Messiers are just fuzzy objects when viewed through simple binoculars.

Next stop is the Lagoon Nebula; M8. This time look to the right side of Sagittarius, and using the “Teapot,” look above the spout to locate M8. This Messier Object lies closest to the direction of the center of the Milky Way Galaxy. Using binoculars on a clear night, you can see some of the nebulosity of M8 imbedded in a “rectangular” grouping of stars. I have had the wonderful experience of seeing the Lagoon Nebula with my naked eye while at a dark sky site in northern Pennsylvania.

Right above M8 are two other Messier Objects, M21, and a well-known object, the Trifid nebula, M20. I personally have never been able to resolve either of these Messiers with standard binoculars, but you are welcome to try.

Next stop: If you look directly above M22, about twice the distance of M8, you will see the Eagle Nebula. Years ago, this was just another nice Messier Object, until it became famous when the Hubble telescope took the amazing star birth “Pillars” photo in the Eagle Nebula; see below.

The last stop on our short tour is the Omega Nebula, M17, also known as the “Swan Nebula.” You can find M17 just below the Eagle Nebula. I have always been surprised how easy it is to resolve the nebulosity of this object with simple binoculars. I always see it as a side view of a swan, but with a short neck; check it out.

After locating the Messiers in our short tour, you should continue your search for other Messiers in the southern summer sky. Try to find M11, M23, and M25, all in the region above Sagittarius. Then move over to Scorpius and try to locate M6 and M7 near the scorpion’s stinger. Also M4 and M80 near the primary star of Scorpius, Antares. While you are in the constellation of Scorpius, wander with your binoculars throughout the region of the scorpion’s tail and lower body. This region is filled with groupings of stars.

A note on the above images: The small binocular images approximate the view through seven to ten power binoculars, just remember, that the actual images you see will indeed be small fuzzy objects. The images labeled “Large Telescope” actually represent the view of these Messier Objects using long time exposure astrophotography. The time exposure and the use of filters, etc. are required to see the colors of the gases in the nebulas. Therefore, if you have a large Dobsonian reflector, you would see an image similar to that shown for a large telescope, but without the color. I have personally watched amateur astronomers at star parties creating similar beautiful color photos of nebulas, however, this type of astrophotography is quite tedious and can be quite costly.

The Dance of the Planets:

This is a great month for planets lovers. Throughout the month, as you look towards the southwest, you will see three planets. The brilliant Venus will be closest to the horizon, followed by Mars and then Saturn. By mid month they will be nicely lined up, and by the end of the month, Saturn will move past Mars as it approaches Venus.

Naked Eye Sights: The summer Milky Way. Watch the “Dance of the Three Planets” in the southwestern sky.

Binocular Sights (7 to 10 power): Follow the directions above, and take a tour of the southern sky summer Messier Objects. Then try to find the other seven Messiers listed above. If you are a dedicated Messier Object observer, there are still other Messiers to find in the southern sky. If you have 25 X 100mm binoculars, all of the Messiers will look quite impressive.

Telescope Sights (60-100mm): Of the Messiers mentioned above, M22 will probably look the best through a telescope. If you enjoy planet watching, you have Venus, Mars, and Saturn all in the same region of the sky.

See you next month!

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