NGC 3718 - S-Shape Galaxy in Ursa Major | Astrophotography Tips & Pictures
Updated: May 23, 2023
NGC 3718 is a small but beautiful galaxy in the constellation Ursa Major. It is not far from other deep sky objects that are much easier for beginners like M81 or M106. In this post, you will find information, images, and tips to photograph this beautiful galaxy.
Object Designation: NGC3718, Arp 214
Also known as: N/A
Constellation: Ursa Major
Object Type: Barred Spiral Galaxy
Distance: 42-52 million light-years away
Magnitude: 10.6
Discovery: William Herschel on April 12, 1789
NGC 3718 is difficult to capture for beginner astrophotographers due to its small size and how faint it is, but it is such a rewarding target! Being in Ursa Major, it is possible to observe it for most of the year but gets at its highest in the sky during the Spring season.
Below you will find our best attempt at imaging NGC 3718, with over 22 hours of total integration time!
NGC 3718 Astrophotography with a Refractor Telescope and Monochrome Camera
April 2023
I had seen this tiny galaxy pop up on SkySafari a few times and was always intrigued by its beauty. I never had the courage to capture it knowing that our largest telescope only has a focal length of 655mm. Indeed, small galaxies like this one are best captured with telescopes that have long focal lengths, around 2000mm for example.
During processing, I had to crop a lot to get this nice view of the two objects and work extra hard to not bring out the noise too much which was definitely difficult. The result turned out nice besides the kind-of choppy background, and the details/color in the galaxies were very exciting to reveal!
The galaxy above NGC 3718 is NGC 3729, which we'll cover later. The tiny group of galaxies just to the bottom left of the main target is Hickson Group 56 (H56).
Click the image for the full-resolution version!
GEAR USED:
Camera: QHY600M
Telescope: Stellarvue SVX130
Mount: 10Micron GM1000 HPS
Guiding: ZWO ASI 290MM Mini
Accessories: Moonlite Nitecrawler focuser / Pegasus Astro Ultimate Powerbox
Processing: Pixinsight, with RC-Astro plugins
ACQUISITION DETAILS:
Total Exposure Time: 22.5 hours
Exposure Time per frame: 10 minutes
Filters: Chroma 3nm R/G/B
Gain: 56
How to Locate NGC 3718
NGC 3718 is in the very popular constellation of the big bear: Ursa Major. It is small and faint, so be aware that it will likely be difficult to spot through an eyepiece.
To find it, first, look towards to north and spot the large and obvious constellation of Ursa Major, more specifically, the "Big Dipper" asterism. The Big Dipper is made up of 7 bright stars and looks like a saucepan. Ignore the handle for now, and only look at the bowl section, which is four stars. The bottom two stars of the saucepan are Phecda and Merak.
NGC 3718 is located just "under" the saucepan shape of the Big Dipper asterism, almost exactly between the two bright stars but slightly closer to Phecda.
We of course recommend using a large telescope to observe NGC 3718. It may be possible to spot it with good binoculars under a very dark site, but it probably will not excite you much as it will look like a tiny dot of light.
NGC 3718 is not far from several Messier objects also located in Ursa Major, like the M109, M97, M108, M81, and M82.
The best time to observe and photograph the NGC 3718 is in Spring.
NGC 3718 Galaxy Information
NGC 3718 is a barred spiral galaxy seen edge-on. Yes, edge-on. It may look like a face-on galaxy in our picture, but the blue parts you see in NGC 3718 are not actually the spiral arms, more info on that in a bit!
The best feature of NGC 3718 is its distorted shape. The "S" shape is likely due to gravitational pulls from other nearby galaxies, in particular NGC 3729 which can also be seen in our image above.
NGC 3729 is massive, and may also have pulled NGC 3718's spiral arms from one side with its tidal forces, giving it a thinner shape than what it would normally have. NGC 3729 is now considered to be a dwarf companion of NGC 3718.
NGC 3718 by the Hubble Space Telescope
NASA used the Hubble Space Telescope to capture a section of NGC 3718 and published the image on May 24, 2022. It shows about half of the galaxy, where both the core and the dust lanes are clearly visible. It is a beautiful shot that shows nice blue colors in the arms mixing up with the yellow/red hues of the barred core.
NASA explains that the core is so difficult to see both visually and in photographs, that they had to use an infrared filter for the bright region to peak through the thick dust lanes. You can see the full image below.
Looking more carefully at this visible light + infrared composite, it is much easier to understand how NGC 3718 is a galaxy seen edge-on and not face-on.
You can tell by the dust lanes that this is seen as an edge-on thin disk, and that the blue light around it is just part of the huge blob of light and not the actual spiral arms.
Core and Dust Lanes of NGC 3718
A research article published on March 10 2009 provided a ton of information on NGC 3718. The researchers found out that NGC 3718 has a complex and asymmetric structure, with a warped disk and a prominent dust lane that obscures much of the galaxy's interior. They also identified several regions of active star formation within the galaxy.
They also investigated the galaxy's environment and found that it is part of a small group of galaxies that includes not only NGC 3729 and several smaller dwarf galaxies.
They also detected evidence of gas interactions between NGC 3718 and its neighbors, which may have triggered the galaxy's recent burst of star formation. You can read the full article by clicking on the image.
The picture attached shows, on the left, the galaxy as a whole where the central dust lane and diffuse spiral arms are visible. On the right, you can see an R-band image of the central region taken. You can see the bright nucleus of the galaxy, as well as some of the thick dust lanes around it.
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NGC 3729
NGC 3729 is the second-largest galaxy visible in our photograph and can be seen above NGC 3718. It is also located in Ursa Major and lies about 52 million light-years from Earth. The distance between NGC 3729 and NGC 3718 is believed to be around 60,000 light-years.
NGC 3729 has a compact structure, with a diameter of around 35,000 light-years. It has a bright central bulge surrounded by a disk of gas, dust, and stars. It has spiral arms rich in star-forming regions.
NGC 3729 also has a faint halo of stars that extends beyond the visible edge of the galaxy, and you can easily see this in Hubble's picture above. It is believed that the halo contains old stars that were pushed away from the galaxy over time.
How to Process NGC 3718
Processing this galaxy was difficult because it is very small in our field of view, and having to crop so much meant sacrificing quality.
The main issue I faced here was the noise in the background. To me, the background as it is right now appears choppy and not very clean. This is mostly because I focused too much on bringing out the details within the galaxy that I didn't pay enough attention to the background while processing the data. This is something I'm usually always careful about, but I guess I chose a day when I was too tired to process, I don't know.
I also did not drizzle this data, which was a mistake as I am undersampled and would have benefited from drizzling.
If you would like to learn how I process all our images, you can access our full "follow along" guide that contains 20 lessons, walkthrough tutorial videos, our custom pre-sets for your dashboard, and even raw data HERE.
It also includes a section on how to download and process data from the James Webb Space Telescope.
The file is updated whenever I decide to tweak my workflow or add more to it, and you always get the updates for free!
How much data can you get with each filter on NGC 3718?
If you were curious to see how the data looked for each filter, you can see the R, G, and B masters below! The B data looked the most detailed, while the R and G data looked almost identical.
The glare you see in the bottom left of the red picture is just a glare from a bright star that was just out of the frame. We're currently dealing with bad tilt and the red channel was affected the most.
Utah Desert Remote Observatories
NGC 3718 was captured using our 655mm refractor telescope and monochrome camera hosted at Utah Desert Remote Observatories. By having an astrophotography rig at a remote observatory under dark skies, we were able to dedicate several nights to the object without the need to drive to the desert and set up our gear multiple times. To discover more about remote observatories, check out the video below.
If you would like to permanently install your rig next to ours under desert skies, you can contact the owner at info@utahdesertremote.com
NGC 3718 FAQ
What is NGC 3718?
NGC 3718 is a barred spiral galaxy seen edge-on.
In which constellation is NGC 3718 located?
You can find NGC 3718 in the constellation Ursa Major.
How big is NGC 3718?
NGC 3718 has an apparent size of about 9.2 by 1.5 arcminutes. It has a diameter of 35,000 light-years.
How far is NGC 3718?
NGC 3718 lies at a distance of about 52 million light-years from Earth.
How long should my exposure time be when photographing NGC 3718?
We decided to do 600-second exposures (10 minutes) when capturing NGC 3718. This worked fine for us at f/5 from a Bortle 2 site. We recommend doing 300-second exposures or double that if you don't want to deal with too many files.
Should I use a filter to image NGC 3718?
NGC 3718 is a broadband target and does not seem to be very rich in HA. We personally have not spent any time on this object with a hydrogen alpha filter, but nothing stops you from trying if you're hoping to see something there. Its dwarf galaxy, NGC 3729, is thought to contain more HA.
What equipment do I need to photograph NGC 3718?
You can image NGC 3718 with a DSLR or mirrorless camera and telescope. We suggest a telescope with a long focal length for this galaxy, like a 12" Newtonian.
If you're a beginner and want to stick to refractors, the Askar FRA600 can be a good option for the price.
Final Thoughts
NGC 3718 is a small, faint, and overall difficult target to process. It is a great target for color cameras and is best imaged from a dark site with a large telescope. It is a great target for astrophotographers looking for a challenge during Galaxy Season!
Have you imaged NGC 3718? If so, upload your picture in the comments! We'd all love to see your work :)
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