Updated: May 23
IC 342 is a rarely photographed galaxy not far from popular beginner targets like the Heart and Soul Nebulae. IC 342 is best known as the "Hidden Galaxy" because it lies behind thick Milky Way dust. In this post, you will find information, images, and tips to photograph this beautiful galaxy.
Object Designation: IC 342, Caldwell 5, UGC 2847, PGC 13826
Also known as: The Hidden Galaxy
Object Type: Intermediate Spiral Galaxy
Distance: 11 million light-years away
Discovery: W.F. Denning in 1890
The Hidden Galaxy can be difficult to capture as well as process, so we wouldn't recommend a complete beginner to attempt this target until they have a few other deep-sky objects under their belt. Below you will find our best attempt at imaging IC 342, with over 34 hours of total integration time!
IC 342 Astrophotography with a Refractor Telescope and Monochrome Camera
I was looking for an interesting target to shoot using my 655mm refractor telescope and was looking for something that is not popular when I stumbled upon IC 342. Knowing it might be difficult to shoot, I decided to aim for at least 30 hours of total integration time and stopped when I reached 34 hours.
As you can see below, the Hidden Galaxy has a bright yellow core, nicely defined orange/blue spiral arms, and is so rich in Hydrogen Alpha! Later in this post, we will show you what each channel looked like before being combined, and talk more about its star-forming regions.
Click the image for the full-resolution version!
Telescope: Stellarvue SVX130
Mount: 10Micron GM1000 HPS
Guiding: ZWO ASI 290MM Mini
Accessories: Moonlite Nitecrawler focuser / Pegasus Astro Ultimate Powerbox
Processing: Pixinsight, final touches in Lightroom and Topaz Suite
Total Exposure Time: 34 hours
Exposure Time per frame: 10 minutes
Filters: Chroma 3nm R/G/B/H
How to Find the Hidden Galaxy
Obviously, with a name like "The Hidden Galaxy", you can expect IC 342 to be a little tricky to find... Well, it doesn't have to be too difficult if you are good at star hopping or own a GoTo mount.
The first thing you need to do is locate the constellation Camelopardalis. This is easier done by first spotting the bright W shape of Cassiopeia, which is very close to the galaxy we are hunting. Looking at the iconic "W" shape, start from the bright star on the very left known as "Segin" or "Epsilon Cassiopeiae". From there, make your way to Camelopardalis, which lies between Cassiopeia and Ursa Major. You should be able to find IC 342 as you near the constellation, near the variable red star BE Camelopardalis.
The Hidden Galaxy is not visible to the naked eye and is very difficult to see with binoculars or telescopes, but it will appear as an elongated smudge of light if you observe from a dark enough location. Obviously, the best way to find the galaxy is by using a GoTo mount and a high-quality telescope from a Bortle 1 or 2 site.
IC 342 Galaxy Information
IC 342 is an intermediate spiral galaxy that has been studied extensively by scientists despite being located behind a veil of galactic matter. Luckily, IC 342 is seen almost perfectly face-on, making it much easier to observe and research. The spiral arms are very well-defined and become even more interesting through different wavelengths.
IC 342 is one of the closeby spiral galaxies that look similar in shape and size to our Milky Way.
IC 342 by NASA
NASA aimed the Hubble Space Telescope at IC 342 a few times and was able to get a full mosaic done of the galaxy in 2019. The picture reveals a beautiful bright core, which appears to be barred, as well as dark dust lanes in the spiral arms. The galaxy goes from yellow to blue-dominant as the arms extend away from the nucleus.
You can see the image below in all its glory!
IC 342 is suspected to have had an impact on how the galaxies in our local group, including our Milky Way, evolved over the years. This is because despite being approximately 11 million light-years away, IC 342 is technically still not far in astronomical terms, and so it might have had gravitationally influences on the other galaxies around.
On the image on the left, you can see yet another image of the galaxy taken by the Hubble Space Telescope.
This time, you can view the central region of IC 342 with hot blue active regions of star formation. The dark and red areas around the center are cooler.
The image was taken on July 3rd, 2017, and is a combination of visible and ultraviolet light, taken with HST's wide field camera.
The core of IC 342 is an HII nucleus, known to host ionized hydrogen and create a vast number of new hot stars.
Why is IC 342 called “The Hidden Galaxy”?
IC 342 is known as the "Hidden Galaxy" because it lies behind thick interstellar dust clouds of our Milky Way. There are also a high number of Milky Way stars and various cosmic gases that impact how we view IC 342. Being in Camelopardalis, the Hidden Galaxy is also very close to the galactic plane of our Milky Way (with a latitude of just 10.5 degrees from the galactic equator), which limits our visibility on the galaxy even more.
Because of that, IC 342 is best observed using infrared, radio, and other long wavelengths as these are able to peak through the Milky Way dust.
If the foreground between Earth and IC 342 wasn’t so busy and full of matter, the Hidden Galaxy would no longer be hidden and would be one of the brightest galaxies in our night sky. It is also believed that it would have been discovered earlier than 1892, and who knows, it could even have been found during Charles Messier’s era and earned a spot in the famous Messier Catalog!
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A Galaxy Rich in Hydrogen Alpha
IC 342 is similar to the Fireworks Galaxy (NGC 6946) because both are famous for being hidden behind Milky Way dust and very active in star formation!
Star-forming regions are best seen in galaxies using a Hydrogen Alpha filter, which is why we captured our image in "RGBHa" and not just "RGB". This allowed us to reveal so much of the red star nurseries throughout the spiral arms of the galaxy. You will be able to see what our Master HA file looked like by itself further down in this post and be in awe of the amount of HA visible.
IC 342 is a well-studied galaxy, the hydrogen alpha regions being of course a main aspect of the research done.
Using SOFIA (NASA’s Stratospheric Observatory for Infrared Astronomy), scientists were able to map the molecular clouds around the core of IC 342.
The map you see here shows hot and cool gas at two different wavelengths, 158 microns (ionized carbon) and 205 microns (ionized nitrogen). These wavelengths were able to penetrate the thick clouds of dust from our Milky Way.
On this map, the cooler gas (carbon) appears from matter that will soon create new stars. The other wavelength (nitrogen) shows hot gas from stars that have already fully formed.
Researchers believe that a huge peak of star formation activity recently occurred in IC 342, so maybe the galaxy wasn't as active in the past. Below you can see a picture taken in infrared by NASA's Spitzer telescope using the infrared array camera (IRAC). NASA describes this image as a "Spider web of stars", and they're not wrong!
The center of the galaxy in this infrared image appears extremely bright, and that is not just because of the supermassive black hole present there! Scientists define this bright area as an enormous burst of star formation which is happening in a small compact area.
The IC 342/Maffei Group
IC 342 is part of the IC 342/Maffei group of galaxies, which is, in turn, part of the Virgo Supercluster. The group is named after two galaxies because it has now become two different subgroups, the IC 342 group, and the Maffei group. The name of each group is chosen after their largest and brightest member.
After several years, researchers discovered that the two subgroups were not related in any way, and had no gravitational link. The IC 342 group includes 11 members, while the Maffei group is home to 8 galaxies. You can see the Maffei 1 and Maffei 2 galaxies in the image below, taken by NASA's WISE instrument and even showing a part of the famous Heart Nebula!
The IC 342 group is the closest group of galaxies to our own Local Group!
How to Process the Hidden Galaxy
Processing the Hidden Galaxy was not very easy, but it was super fun as this was the first galaxy I processed in a long while.
The first challenge is the number of stars both around the galaxy, and overlapping it. Thankfully, StarXTerminator did a fantastic job removing them as usual, and I was able to process the galaxy without being bothered by the stars.
Another challenge was to bring out the details in the galaxy evenly, without blowing up the core or making it look unnatural. Lastly, I had to combine the Hydrogen Alpha data with the RGB file, and this was done using PixelMath using a simple equation.
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 the Hidden Galaxy?
We love to show you what you can expect with each filter whenever we take a new image. It's usually much more exciting in a nebula, but it can also be nice to see in a galaxy especially when HA is involved.
Below you can see the master files for each R, G, B, and HA channel. R, G, and B obviously look very similar and uninteresting, but be sure to take a look at how much data there was in the HA master! The bright areas you see in the H file are all star-forming regions, and they're all over the spiral arms, and even just around the core! This shows why HA is worth shooting in this galaxy.
Utah Desert Remote Observatories
We used our refractor telescope and monochrome camera installed at Utah Desert Remote Observatories to capture the Hidden Galaxy. Having an astrophotography rig at a remote observatory under dark skies allowed us to spend this many hours on the object without having to drive out to the desert, set up and pack up several times.
If you want to learn more about remote observatories, be sure to watch the video below for more information!
If you would like to permanently host your telescope next to ours under amazing desert skies, you can contact the owner at firstname.lastname@example.org
IC 342 FAQ
How did the Hidden Galaxy get its name?
IC 342 got the nickname "Hidden Galaxy" because it is behind layers of dust and gas from our Milky Way. It also is not very far from the galactic plane, making it difficult to be seen.
In which constellation is IC 342 located?
You can find the Hidden Galaxy in the constellation Camelopardalis.
How big is IC 342?
The Hidden Galaxy has a diameter of 75,000 light-years and a radius of about 37,500 light-years. From Earth, it has an apparent size of 21.4 x 20.9 arc-minutes.
How far is the Hidden Galaxy?
IC 342 lies approximately 11,000 light-years away from Earth. It is one of the closest galaxies to the local group.
How long should my exposure time be when photographing IC 342?
The Hidden Galaxy is faint compared to most other large galaxies, so we decided to do 600-second exposures (10 minutes). This worked really well for us at f/5 from a Bortle 2 site. We would recommend doing 300-600 second exposures.
Should I use a filter to image IC 342?
IC 342 is a great broadband target, just like all other galaxies, so you technically do not need any filter to capture it and get a good result. For the best possible image, we strongly suggest also shooting this galaxy with a hydrogen alpha filter, which will allow you to reveal all the star-forming regions in the spiral arms which glow in red.
What equipment do I need to photograph the Hidden Galaxy?
You can image IC 342 with a DSLR camera and telescope, as it is completely fine as a broadband target. As for the focal length, we suggest a telescope with at least 500-600mm.
For the best possible results, use a larger telescope and shoot the target in broadband with added hydrogen-alpha data.
For a beginner telescope, the Askar FRA600 can be a good option for the price. We don't recommend photographing IC 342 without a telescope. Although not impossible, using just a camera lens and sky tracker will likely result in a disappointing image for this specific target.
IC 342 is considered an advanced target for astrophotography because it is faint and behind a lot of interstellar dust. We did not find it to be too difficult to shoot and process, mostly thanks to it being seen face-on. We definitely recommend shooting hydrogen alpha on top of your RGB data to really make all the star-forming regions pop, as this galaxy is very rich in HA.
Have you imaged the Hidden Galaxy? If so, upload your picture in the comments! We'd all love to see your work :)
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