Updated: Oct 9, 2020
Featured on The Astrophotographer's Guidebook.
IC 5146, the Cocoon Nebula, is a reflection and emission nebula in the constellation Cygnus.
It has a similar shape to the Iris nebula, but while the Iris looks like heaven in space, this target would be hell instead.
Object Designation: IC5146
Also known as: The Cocoon Nebula
Object Type: Reflection/Emission Nebula
Distance: 3,262 light-years away
Discovered in: 1894
Like the Iris nebula, the Cocoon nebula is surrounded by interstellar dust lanes and looks like it has a long tail on one side!
Do not center this target in your camera unless you are using a large instrument, because capturing its dark tail makes the overall image more impressive than a close up.
Imaging the Cocoon Nebula with a cooled OSC Camera
July 17, 2020
With the same telescope used for our first attempt at the Cocoon Nebula back in 2017 and the same sky quality (Bortle 3), we decided to re-image this target this time using an astrophotography-dedicated cooled camera, the QHY128C OSC camera. We spent a total of 4 hours and 15 minutes of exposure, and are happy with the results!
Camera: QHYCCD 128C
Telescope: Orion 8" Astrograph f/3.9
Total Exposure Time: 4 hours and 15 minutes
Exposure Time per frame: 180 seconds
Filters: ZWO IR Cut Filter
Imaging the Cocoon Nebula with an unmodified DSLR camera
October 28, 2017
We only spent one hour on this target before switching to the Helix Nebula, but we were really surprised with the result even with such low integration time!
We initially did not plan to image this object at all that night, but realized that our main target, the Helix, was still a bit too low in the horizon to be photographed so we "killed" some time on the Cocoon. If we knew it would look this impressive with just one hour of exposure time, we would have imaged it all night!
One hour of total exposure and very basic processing on IC 5146!
Camera: Canon 7D Mark II
Telescope: Orion 8" Astrograph f/3.9
Mount: Atlas EQ-G motorized Mount
Total Exposure Time: 1 hour
Exposure Time per frame: 3 minutes
20 lights - 15 Darks - 15 Bias
The core of the Cocoon nebula shows a bright star surrounded by black, pink and blue gas.
You should be able to get a lot of details on the nebula itself with a large telescope, but most people prefer to capture it wide field to include its long tail of dark dust.
Locating the Cocoon Nebula
The Cocoon nebula is visually interesting if observed from a very dark zone, mostly because instruments need really good skies to reveal the dark lanes next to the nebula. If you do not have a large instrument or would prefer to use a small telescope, you will still be able to contemplate the cocoon as a glowing, diffuse circular object.
Locating the Cocoon is not an easy task, it lies in the high flying constellation of Cygnus, but is closer to Lacerta’s stars. It is near M39, a not-so impressive cluster which is also not easy to find. The best way to land on IC 5146 manually is to draw an imaginary line between the very bright star Deneb and 4 Lac, the star in Lacerta closest to Cygnus. Your target will be about 3/4 of the way from Deneb.
Central star lights up the nebula
Has interstellar dust lanes forming a tail, called Barnard 168
IC 5146 is a compact star forming region
Single Shot & Processing of the Cocoon Nebula
Below you can see a 3-minute single shot of IC 5146 with both our DSLR camera (left) and the QHY128C OSC camera (right). It does not look really great at first sight, but stacking makes a huge difference here! You can also clearly see the dark dust lanes, which can help you frame the nebula to your liking.
As for the processing, we used the same workflow we always used, which can be downloaded as a PDF guide HERE.
The Cocoon Nebula is a magnificent target that is popular for amateur astrophotographers due to its tail of dark interstellar dust. It is a great object for regular RGB colors so a DSLR or a OSC cooled camera is perfect for the job!
We would love to attempt this with a professional grade telescope one day and maybe even in Narrowband!
Have you captured the Cocoon Nebula? Attach your image in the comments and let us know what equipment you used!
Part of: The Astrophotographer's Guidebook
Description: Discover 60 Deep Sky Objects that will considerably improve your Imaging and Processing skills! Whether you are a beginner, intermediate, or advanced astrophotographer, this detailed book of the best deep sky objects will serve as a personal guide for years to come! Discover which star clusters, nebulae, and galaxies are the easiest and most impressive to photograph for each season. Learn how to find each object in the night sky, and read our recommendations on imaging them in a quick and comprehensive way. Each target in this guide contains our advice on imaging, photos of expected results, and a useful information table. We've also included a few cool facts about each target, a map to find it in the night sky, and more!