Stephan’s Quintet is a visual grouping of five distant galaxies in the constellation of Pegasus. The group is named after the astronomer Edouard Stephan who first observed and documented the group in 1877. The group is also known by it more formal designation – Hickson Compact Group 92.
Although all five galaxies appear to be located near each other in space, only four are actually in close physical association. NGC 7320, the very blue galaxy at the lower left, is a foreground galaxy and is much closer to us than the rest. Astronomers estimate that NGC 7320 is approximately 40 million light years from earth. The other four, NGC 7319 (upper left), NGC 7318A and NGC 7318B (center) and NGC 7317 (lower right) are much more distant. Estimates of their actual distance range from about 210 to 340 million light years from earth.
Astronomers believe that NGC 7319, NGC 7318A, NGC 7318B and NGC 7317 will all eventually merge into each other. Evidence of their close interactions is seen in their distorted shapes.
Also note that NGC 7319, NGC 7318A, NGC 7318B, and NGC 7317 are all much redder than the foreground galaxy NGC 7320, which indicates that they are much older than NGC 7320. Astronomers believe that NGC 7320 was going through an intense phase of star formation at the time the light captured in these images left that galaxy 40 million years ago.
Acquisition Date: September 3 – 4, 2005
Location: Mt. Laguna, San Diego County, California
• Imaging Scope – RC Optical Systems 10″
• Imaging Camera – SBIG ST-10XME
• Filters – Astrodon Gen 1 clear, red, green and blue filters
• Guiding – On camera.
• Mount – Astro-Physics 1200GTO
• Imaging Camera cooled to -22
• Exposures – luminance – 18 x 360 seconds, red 6 x 360 seconds, green 6 x 360 seconds, blue – 6 x 360 seconds
Processing: MIRA AP, PixInsight and Photoshop CC were used to process the images.
Click on the image below to see a larger version.