Stephan’s Quintet (Arp 319)
Stephan’s quintet (NGC 7317, 7318A, 7281B, 7319, and 7320) in the constellation Pegasus is a grouping of 5 galaxies in a 3.5 arc-min area. The largest and brightest of the group, NGC 7320, is located in the lower left of center. Due to difference in red shift, the conventional view is that NGC 7320 is not part of the other 4 galaxies in the group. It is instead actually part the nearby NGC 7331 group. However there is evidence of a connecting tail extending from 7320 which implies interaction with the the other galaxies. Some astronomers, such as Halton Arp, maintain that because of this the current beliefs about red shift should be re-examined.
The galaxies 7318A and B located near the center of the image are quite interesting as well. Not only are they interacting but they also have differing red-shifts. Galaxy 7318B is currently moving toward the others at high speed setting up a tremendous shock wave larger than our own milky way galaxy in size.
Location was Crow Valley Campground in the Pawnee Grasslands just north of Briggsdale, CO. Temperature was 44°F and humidity was 56%. The sky was mostly clear with a few thin clouds, no wind, turbulence around 6/10, and transparency varied from good to very good. Fifteen minutes of video taken with Celestron Nexstar11 telescope, APT wedge, Meade F3.3 focal reducer, and a Astrovid Stellacam II video camera. Camera set at 9/14 gain, integrate 256 (8 sec), and medium gamma. Images were dark subtracted and flat field corrected with ImagePlus, aligned and stacked with Registax3.