Updated: May 17
The Rosette Nebula is one of the largest, most beautiful, and also most popular targets for amateur astrophotographers. Yet, it took us 4+ years before attempting it ourselves. In this post, we will share a ton of tips and information for both imaging and processing the Rosette Nebula, and show all our attempts at photographing this target!
Object Designation: NGC 2237, NGC 2238, NGC 2239, NGC 2244, NGC 2246
Also known as: The Rosette Nebula, The Skull Nebula
Object Type: Emission Nebula with an Open Cluster
Distance: 5,219 light-years away
Discovered in: 1690 by John Flamsteed
NGC 2237 is often used to describe the nebula as a whole.
NGC 2238, 2239 and 2246 are specific parts in the gases within the nebula.
NGC 2244 designates the open cluster in the nebula.
The composite image on the right was taken by the Chandra X-Ray telescope and shows several regions of the Rosette Nebula. The cluster is clearly visible here, with plenty of bright stars illuminating all the gases within the nebula.
The Rosette Nebula and NGC 2264 with a DSLR Lens Widefield
Time to image the Rosette Nebula without a telescope! NGC 2244 is a great wide-field target, and with a DSLR lens you can also include another popular deep sky object nearby: NGC 2264.
NGC 2264 refers to a bright nebulous section of the sky which includes:
The Christmas Tree cluster
The Cone Nebula
The Fox Fur Nebula
The Stellar Snowflake Cluster
NGC 2244 and NGC 2264 are close to each other, and you can see in our picture that their gases expand so much that they even seem to interact! Imaging the Rosette Nebula without a telescope is exciting as long as you get your framing right and can include the Christmas Tree as well. We did our best to fit both in the frame, with the correct orientation, and voilà!
This was taken with 15 hours of integration time from our Las Vegas backyard. Click the image to see it in higher resolution!
Camera: ZWO ASI 2600MC
Lens: Samyang 135mm f/2
Mount: ZWO AM5
Power: Jackery Lithium Battery
Processing: Pixinsight, with RC-Astro plugins
Total Exposure Time: 15 hours
Exposure Time per frame: 6 minutes
Imaging the Rosette Nebula in Bicolor for 20 hours
December 2021 - January 2022
As our last target for 2021, we decided to try the Rosette in bicolor this time, and spend 20 hours on it:
12.5 hours in Hydrogen Alpha, from the comfort of our backyard
7.5 hours in Oxygen III, 1 hour away in the cold desert
We then combined the two channels in bicolor to obtain the result below. If you are not sure how to do bicolor imaging, be sure to read or watch our quick tutorial about bi-color combination!
The Rosette Nebula - 20 hours in bi-color
Telescope: Stellarvue SVX130
Mount: 10Micron GM1000 HPS
Guiding: ZWO ASI 290MM Mini
Accessories: Moonlite Nitecrawler focuser / Pegasus Astro Ultimate Powerbox
Power: Jackery Lithium Battery
Processing: Pixinsight, with RC-Astro plugins
Total Exposure Time: 20 hours
Exposure Time per frame: 10 minutes
Filters: Chroma 3nm H/O
Get similar results when processing your images by downloading our step-by-step processing workflow. It contains an 80-page PDF file, walkthrough videos, raw data, and our PixInsight shortcuts!
When you image an object that is full of intricate details like the Rosette Nebula, it is always a good idea to take the time to zoom in all the way and explore each structure of gas.
While doing just that, I fell in love with a specific area that is home to a large and impressive pillar of gas. It is hard to say if this is a pillar similar to the ones found in the Pillars of Creation, or if it is a Bok globule, like the ones in the Pelican Nebula... But it is so pretty!
In case you have some difficulties locating this area in our main image, the blue gas on the upper left is where the core of the Rosette is!
What do you think of this close-up view? I am in love with the amount of gas visible and all these colors interacting!
Imaging the Rosette Nebula from Home with a Small Telescope
February - September 2021
This is Dalia's first-ever nebula captured by herself! 🥳
It took her so many attempts at processing it with PixInsight that the image was finally done 7 months later... in September. Here is what she had to say when she shared it on our Instagram page:
"Hey pals, I finally finished processing my project from earlier this year! If you can’t tell, it’s meee - Dalia! I collected the data on my own and processed the image on my own... And with Pixinsight! (GASP) 😳
I’m pretty proud of it but I’m still not satisfied with how it came out. But are we ever? 😭😂
This is the Rosette Nebula, aka NGC 2237. 🌹 I took this over 2 nights for about 3-4 hours in a Bortle 9 zone (my backyard)."
Camera: ZWO ASI071MC
Telescope: Radian Raptor 61
Mount: Atlas EQ-G motorized Mount
Guiding: ZWO ASI290MM Mini
Acquisition: ZWO ASIAir Pro
Total Exposure Time: 4 hours
Exposure Time per frame: 5 minutes
Calibrated with 15 Darks and 15 Flats
Filter used: Radian Triad Ultra
If you own a cropped-sensor camera and would like a similar composition as the one seen above, be sure to image the Rosette Nebula with a small telescope! For this specific shot, Dalia used a beginner refractor which has a wide focal length of 275mm. To ensure that none of the nebulosity in and around NGC 2337 gets cut by your framing, we suggest using a telescope that has a maximum focal length of about 360mm. Some popular options for astrophotography telescopes in that focal length range include:
William Optics RedCat 51 | Focal Length: 250mm
Askar FRA300 Pro | Focal Length: 300mm
William Optics ZenithStar 61 f/5.9 Doublet APO | Focal Length: 360mm
If you own a full-frame camera instead of an APS-C, then you should be safe with using a slightly larger telescope! Just be sure to triple-check your composition before launching your sequence of images.
Imaging the Rosette Nebula for the first time with a $4,800 Telescope
Tonight, I will be heading to a Bortle 2 zone and use a very fast Newtonian reflector telescope to image this "flower" in space.
OPT decided to send us a new toy to try out for a bit. They knew we started out with the Orion 8" Astrograph f/3.9 and that we've always been in love with fast reflectors!
We'll talk about the telescope more in-depth later in this post, but you can see what the beast looks like on the right!
Lucky for us, the telescope came with an Optec focuser! We had never used electronic focusers before, but we now had a reason to learn how to!
Here is our first-ever image of the Rosette Nebula, 3 hours in total taken from a Bortle 2 zone.
NGC 2244 using the Takahashi E-180 and the ZWO ASI 1600MM
Camera: ZWO ASI 1600MM
Telescope: Takahashi Epsilon-180
Guiding: ZWO ASI290MM Mini
Acquisition: ZWO ASIAir
Total Exposure Time: 3 hours
Exposure Time per frame: 3 minutes
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Processing the Rosette Nebula
The image processing part was not difficult but very annoying. The Takahashi E-180 telescopes are famous for being very well built and being able to hold collimation for many months. Sadly, our loaner seemed to have lost its collimation either before or during the shipping.
As you can see on the Hydrogen-Alpha frame below, the bottom left corner of the image shows elongated stars. Although it is not such a major issue, it still affects a part of the image that is too large to be cropped out. This issue is even more noticeable once all the data is stacked (which you can do with programs like PixInsight or Deep Sky Stacker) because the stars are then brighter and the elongation is more visible.
We do not have the required collimation tools and, to be honest, patience to fix this issue knowing we have a limited time available with this telescope.
We tried to collimate the secondary mirror for several days (thanks to Jorge for your help!) and feel like we managed to correctly do it, but the images show some tilt, which is probably due to the primary mirror. Sadly, we do not feel comfortable taking the mirror out and decided to return the telescope after a couple of weeks.
If you'd like to learn more about how I imaged the Rosette Nebula with this telescope, you can watch the video above!
Now on our more recent attempt in 2021, processing this image was so much fun! I actually went back to the data a few weeks later because the second version of StarNet became available, which had a great impact on the image processing done here. If you do not know how to install and use Starnet for PixInsight, be sure to check out our tutorial!
We never use Adobe Photoshop when processing our deep sky images, but I did try to open the file in Photoshop at the end anyway to see if I could enhance it in any way. Well, I couldn't. I was 100% satisfied with what came out of the PixInsight oven and so did not modify the image further.
What did each narrowband channel look like?
Below you can see what one hour of total exposure on each channel revealed. We used three filters to capture the Rosette Nebula:
Sulfur II (center)
Oxygen III (right)
The Hydrogen Alpha data is obviously the one that shows the most signal! As for the stars in the open cluster region, they are as equally bright through each filter.
Combining these three channels using the Hubble Palette (the Hydrogen Alpha data being mapped to green, the Sulfur II data to red, and the Oxygen III data to blue), gave us some great colors to work with. After using the SCNR process to remove most of the green hue, the beautiful blues and oranges started to pop out nicely, ready to be enhanced!
The telescope used: Takahashi Epsilon-180 f/2.8
Let's talk a bit more about the telescope we used to get this image of the Rosette Nebula.
As we explained many times, our first telescope in our astrophotography journey was the Orion 8" Astrograph f/3.9. A very fast and affordable Newtonian reflector telescope which we reviewed on both our website and YouTube channel.
The Takahashi E-180 is also a fast Newtonian reflector telescope, well, it is a Hyperbolic Newtonian. With a speed of f/2.8, the Epsilon 180 is noticeably faster than our first telescope, meaning we can capture more in less time.
It has a focal length of 500mm, which is perfect for capturing nebulae of medium to large sizes as well as clusters and large galaxies.
Optical Design: Hyperbolic Newtonian
Aperture: 178mm (7")
Focal Ratio: f/2.8
Image Circle: 44mm
Limiting Stellar Magnitude: 14
Tube Length: 19.7"
Tube Diameter: 232mm
Tube Weight: 22 lbs.
How to find the Rosette Nebula in the night sky?
Who discovered the Rosette Nebula, and what is the age of the object? The Rosette Nebula was discovered by John Flamsteed in 1690, and the open cluster in its center is believed to be approximately 4 million years old.
It is best observed in Winter and is located in the constellation of the unicorn: Monoceros. It is also pretty close to the brightest star in the night sky, Sirius! You can easily find your target by looking just right in between the bright star Betelgeuse (Orion's right shoulder) and Procyon (the bright star in Canis Minor).
Monoceros can be found in the Winter Milky Way band, which is much fainter than the popular Summer Milky Way. The brightest star in the area is Alpha Monocerotis, at a magnitude of 3.94 and ten times the sun's radius. Alpha Monocerotis is an evolved giant star of type G, which is the same star class as our sun.
The constellation of Monoceros was outlined by the Dutch globe maker Petrus Plancius in 1612. This, along with Camelopardalis, was only two of twelve proposed constellations to be approved by other astronomers during that year. The story is actually very interesting and you can learn all about it in The Constellations Handbook!
Monoceros represents a unicorn, and southern hemisphere inhabitants can see the constellation all year long!
Using binoculars, one can easily spot the cluster of stars in the center of the nebula. These stars in the center of the nebula can also be seen through a telescope, but the gases are mostly made up of Hydrogen-Alpha, so it can be difficult to observe this object without a filter. The best way to find it visually is to use a small instrument and to of course be under a very dark site. Using a sensitive camera, the Rosette Nebula pops out very easily even with short exposure shots.
The bright open cluster (NGC 2244) can be spotted much easier than the nebula itself, so look out for that!
You can find several other colorful deep sky objects not far from the Rosette Nebula, such as:
NGC 2264 - The Christmas Tree star Cluster and Cone Nebula
NGC 2346 - The Butterfly Nebula (The little one, not the huge Butterfly in Cygnus!)
Messier 50 - A nice open cluster 2,270 light years away, discovered in 1772.
NGC 2359 - Thor's Helmet Nebula
IC 2177 - The incredibly huge and colorful Seagull Nebula
The image on the left shows IC 2177 on the top, and the much smaller NGC 2359 near the bottom left! Both of these nebulae are located in the constellation Monoceros.
Discovered in 5 different parts over time
Also called “The Skull” or sometime the "Rose Nebula"
It is one of the most massive emission nebulae in the sky
I remember being very sad about the collimation issue when shooting the Rosette in 2020, I was of course glad I had the chance to image it with such a wonderful telescope, but I now am super happy I was able to re-visit this target with my current gear. I think the result turned out really good! I have to say I am curious to see if it would be much better with a regular S-H-O combination though, so maybe I'll add SII at some point in the future.
Overall, the Rosette Nebula is a great target for both advanced and beginner astrophotographers. It is large, bright, and easy to capture. It can be a bit tricky to process it right depending on the quality of your data, but if Dalia was able to process hers, trust me, you can easily achieve something good with yours too 😅
Next on our "hunt list" is to photograph the Rosette Nebula again, but this time using our Canon EOS mirrorless camera and a lens on a star tracker. We'd love to capture this colorful nebula wide-field from a dark site with our portable astrophotography equipment. Sometimes, imaging without a telescope and with a lightweight tracker like our Star-Watcher Star Adventurer Pro instead of our heavy astrophotography equatorial mount feels like a much-needed break!
Imaging this was fun! Have you captured the Rosette Nebula? Attach your image in the comments and let us know what you used!
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