HCG 92 - Stephan's Quintet | A Group of Galaxies in Pegasus
Updated: May 18, 2023
HCG 92, also known as Stephan's Quintet, is a compact group of galaxies located in the constellation Pegasus. I imaged this group of very small galaxies from a Bortle 4 zone, and made sure to frame my shot so that a much larger object, NGC 7331would also be visible in the final image!
Object Designation: HCG 92
Also known as: Stephan's Quintet
Constellation: Pegasus
Object Type: Group of galaxies
Distance: Varies. 39 to 340 million light-years away
Magnitude: Varies. 13.9 to 16.7
Discovered in: 1877
Stephan's Quintet is a visual group of five galaxies that appear to be very close to each other. Scientists confirmed that at least four out of the five objects are so close to one another that they are interacting. These four members (HCG 92) are bound by gravity and will merge into one large galaxy in several million years. As for the fifth galaxy visible, it only appears to be close to the group but is actually much, much closer to Earth (39 million light years) than the other four (260-340 million light-years).
NGC 7331 - A beautiful spiral galaxy near Stephan's Quintet
NGC 7331 is an unbarred spiral galaxy that is located really close to Stephan's Quintet. It is much larger than the galaxies in the group and is a welcome addition to any image as it is easy to include it in the frame with most telescopes.
In the past, NGC 7331 was also known as "The Milky Way's Twin" as it was believed to be very similar in shape, size, and structure. This is no longer the case since the 2000s as scientists now believe that our Milky Way is a barred galaxy.
The result I was able to get with my amateur equipment from Earth is visible below. The full image is actually much wider (scroll further down to see it), but I had no choice but to crop it out quite a bit to be able to see the main objects due to the very small size of Stephan's Quintet.
Stephan's Quintet (left) and NGC 7331 (top right) with many more galaxies
GEAR USED:
Camera: QHY600C
Telescope: Stellarvue SVX130
Mount: Paramount MyT
Guiding: ZWO ASI 290MM Mini
Accessories: Moonlite Nightcrawler focuser
Processing: Pixinsight
ACQUISITION DETAILS:
Total Exposure Time: 4 hours and 15 minutes
Exposure Time per frame: 180 seconds
Filters: N/A
Gain: 26
How to Find Stephan's Quintet
Stephan's Quintet, along with the spiral galaxy NGC 7331, can be found in the constellation of the flying horse: Pegasus. The group of objects is located on the Northern edge of the horse, right by the small constellation Lacerta.
You can easily star hop to it by first locating Pegasus' great Square. Start from the bright star Beta Pegasi (also known as Scheat), which is the upper right star in the Pegasus square. From there, slowly make your way toward the closest bright star in Lacerta. You should be able to find NGC 7331 and Stephan's Quintet about three fourth of the way there.
Stephan's Quintet is way too small and faint to be visible with the naked eye or binoculars. A large telescope with a high aperture is needed if you plan on observing this grouping of galaxies.
Stephan's Quintet Photographed from Space
NASA really likes Stephan's Quintet, which is why they imaged the visual group of galaxies with both the Hubble Space Telescope and the James Webb Space Telescope! In fact, HCG 92 is the most studied group of galaxies out there and has been photographed through several complex filters by different space telescopes. Below we will show you the images of Stephan's Quintet taken by both the Hubble and James Webb Space Telescopes.
Stephan's Quintet by the Hubble Space Telescope
September 9, 2009
The picture on the left was taken by NASA's Hubble Space Telescope and shows the four true members of HCG 92, as well as the fifth visible galaxy.
The following objects can be seen:
NGC 7320 - Upper left
NGC 7319 - Upper Right
NGC 7318A & NGC 7318B (currently merging) - Center
NGC 7317 - Bottom left
All of these galaxies are very faint, but the brightest member of the group is NGC 7318B with a magnitude of +13.9.
Stephan's Quintet by the James Webb Space Telescope
July 12, 2022
Now on the right is the same area of the sky but this time taken with the James Webb Space Telescope.
The angle and field of view are slightly different but you can still recognize which galaxies are which. NGC 7320 is on the left, with NGC 7317 on the bottom.
The main difference here are the filters used. The James Webb Space Telescope uses mostly infrared filters, which is why we are able to see much more stars and very faint galaxies in the background, as well as much crisper textures within each galaxy.
Which version do you prefer? Although the colors of the HST are beautiful, we can't help but fall in love with all the details revealed by the JWST. There are hundreds of galaxies of all shapes visible in the background, and the details in the arms of the Quintet's galaxies are just incredible.
Single Shot & Processing of Stephan's Quintet
As usual, we like to show you what our single shots look like before we stack and process our images. On the left image below is a single shot of 3 minutes, un-cropped. You can kind of see NGC 7331 near the center but Stephan's Quintet is difficult to spot. On the right is the final image, slightly cropped just to easily get rid of some weird-looking stars on the edges. As you can see, even that image is too wide to really enjoy the beauty of these objects. This is why I decided to crop it even further, which you can see at the beginning of this post.
Processing this image was not too difficult, but it had its challenges. First, the galaxies are so small that it is hard to really bring out the details and colors within each. They're also very different from one another so you have to be careful not to over-saturate or blow out one object while trying to enhance the others.
If you'd like, you can learn how I process all our images by downloading our guide HERE.
Final Thoughts
Stephan's Quintet is a fun but challenging target. It is best imaged with a large telescope, and including NGC 7331 is a must! To make your life easier, attempt this target from a dark site and only go for it if you do not have an easier object in mind.
Have you captured Stephan's Quintet? Attach your image in the comments and let us know what equipment you used!
Clear Skies,
Galactic Hunter
