Tuesday, August 07, 2007
The Red Necked Emu
On Saturday July the 15th, Leo and I finally had a good evening of observing together. We enjoyed hunting some deep-sky objects, he with the 4-inch Takahashi and I with my 15x80 Binoculars mounted on the SkyWindow. We started of with two very large clusters near the Serpens Cauda / Ophiuchus border, NGC 6633 and IC 4756. These two contrasting clusters are also included in O'Meara's "Hidden Treasures", under the numbers HT 92 / HT 93. With my 15x80 binocular (field of view 3.5 degrees) I could not see both clusters together. I had to turn the SkyWindow from left to right and back again to compare both clusters, but I noticed immediately how different these two open clusters are. I estimated IC 4756 about 45' or 50' in diameter. In a trapezium of 4 bright stars I count at least 50 weaker stars. NGC 6633 looks much more compact, about half the size of IC 4756. However, the individual stars are brighter, and are grouped in a kind of small elongated circle, and a few long straight streamers of stars. These two clusters are wonderful objects for binoculars.

Our next stop was Phil Harrington's STAR 26 ( STAR=Small Telescope Asterism Roster), the Red Necked Emu in Cygnus, The Swan. I had seen it once before in my 4-inch refractor a few years ago, so I knew what I was looking for. The Red Necked Emu looks like a giant propeller with three blades, about 1 degree in diameter. Just start at Gamma Cygni, the orange star at the heart of Cygnus, and move towards Albireo along the neck of the Swan for 2.5 degrees to 34 Cygnus. From there move about 1.5 degrees in the same direction to arrive at 29 Cygnus. This star marks the tip of the Emu's tail. On the image below you can see how the Emu is oriented in the sky. Through my 15x80 it was very simple to find. I think this object is best in 80 to 100 mm instruments, with a large field of view. This strange bird is called Red-Necked Emu because all the stars he consists of are white-bluish, except one orange-reddish star in its neck. This is very easy to see.

Click to enlarge

After this I first freewheeled a little through the Milky Way in Cygnus, a wonderful experience with binoculars. M 29, Albireo, Omicron 1 and 2, are just a few of the stops I made. After that I also made a little tour through Vulpecula: The Coathanger (Collinder 399) The Dumbbell (M 27), and the wonderful open cluster NGC 6940. Although not very well resolved, NGC 6940 stood out well from its surroundings, however I like this object more in my 300mm Newtonian. From Vulpecula I turned back again into the Swan, passing M 39 and on to Mu Cepheus, the Garnet star. In this area we looked at a few open clusters, but because we had some problems identifying them, we will have to revisit this area.

Posted by Math on 08/07 at 11:08 AM | (0) Comments | filed in: Deepsky binocular | Deepsky log | Print