NGC 6188 - Rim Nebula - Fighting Dragons of Ara Astrophotography
NGC 6188 is a colorful emission nebula located in the southern constellation Ara. It is known as the Rim Nebula, but often called the Fighting Dragons of Ara due to the bright center part looking like two dragon heads facing each other. NGC 6188 is one of the most popular objects to capture for astrophotographers who live in the southern hemisphere.
Object Designation: NGC 6188
Also known as: Rim Nebula, Fighting Dragons of Ara
Constellation: Ara
Object Type: Emission Nebula
Distance: 4,000 light-years away
Magnitude: 5.2
Discovery: 1836 by John Herschel
The Fighting Dragons of Ara are best captured during the Winter months in the Southern hemisphere, meaning in June, July, and August. In this post, you will find information on NGC 6188 as well as our attempts at processing it. We'll also talk about another nearby nebula directly linked to the dragons... the Dragon's Egg Nebula.
Rim Nebula Narrowband Astrophotography
Because NGC 6188 is a southern object, we cannot photograph it from our location in Nevada. We still like to process southern objects, so we used Telescope Live to download raw data for this target and see what we could get. We've done something similar for other southern jewels, like the Statue of Liberty Nebula, NGC 1365, Chamaeleon Cloud and more).
This data was captured with a high-quality setup in Australia. The telescope is a Takahashi FSQ-106, the camera an FLI PL16803 (now replaced with a QHY600M), and a Software Bisque mount.
The picture below has a total integration time of 19 hours and was processed using PixInsight. You can see the entire Rim Nebula, with the Fighting Dragons of Ara in the center, and the Dragon's Egg below them.
Want to process your images following our own workflow? Get our PixInsight Processing Guide!
GEAR USED:
Camera: FLI Proline PL16803
Telescope: Takahashi FSQ-106
Mount: Software Bisque Paramount MX+
Processing: Pixinsight, with RC-Astro plugins
ACQUISITION DETAILS:
Total Exposure Time: 19 hours
Exposure Time per frame: 5 minutes
Filters: SHO
How to find the Fighting Dragons of Ara in the Sky?
NGC 6188 can be found in Ara, a constellation that is located in between Scorpius, Telescopium, Norma, and Triangulum Australe. The nebula is located about 4,000 light-years from Earth. The best time to observe NGC 6188 is during the Southern Hemisphere's Winter months.
You can see the object circled on the map below.
Other popular deep sky objects near the Lambda Centauri Nebula include:
NGC 6397 - One of the closest globular clusters to Earth
NGC 6231 - An open cluster that looks like the Jewel Box cluster
NGC 6124 - A young open cluster
NGC 6067 - Another open cluster
To locate NGC 6188, first, find the constellation Ara. From there, try to locate the star Alpha Ara, which is to the North. You can then use this star to make your way towards the constellation Norma. NGC 6188 will be located between these two points.
The Dragon's Egg Nebula
In our image of the Rim Nebula, you might notice a bright blue nebula not too far under the fighting dragons. This is NGC 6164, also known as the Dragon's Egg Nebula!
The image below was also acquired with Telescope Live, this time with a larger telescope. You can see the expanding shell around the Dragon's Egg.
The Dragon's Egg Nebula is believe to be located between 4,000 and 6,000 light-years away.
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Using Telescope Live to Capture Deep Sky Objects
As we said earlier, we used Telescope Live to get the data for the Rim Nebula because of its location. This is a great way to download high-quality data for objects that you've always wished to process, but were unable to capture yourself.
Telescope Live sent us a coupon for you to use if you are planning on giving it a go. The coupon code is "TL4GH" which can be applied when signing up!
Do I Need Filters to Photograph the Rim Nebula?
The Rim Nebula is a bright emission nebula that is full of colors. Those colors are best revealed when imaged in narrowband, as they come from three different gasses, Hydrogen Alpha, Sulfur II, and Oxygen III.
The Rim Nebula can also be captured with a stock DSLR camera or an OSC camera, but expect the object to look mostly all red. This will give you a "true color" version of the target, but not all details will be visible as the small filaments of gas here and there will get lost in that red "sea" of signal.
Processing the Fighting Dragons of Ara Nebula
This was a nice image to process but surprisingly not that easy. The field of view is very wide, so the dragons, which are the main section of the nebula, appear with small details. Bringing these tiny details out without overprocessing the data was a bit tricky for sure.
As always, removing the stars helped tremendously in this task, and using color masks was also a smart move to target different areas of the nebula.
Below you can see what the master file for each filter looked like, that way you can compare the signal of the different channels. We have this type of comparison for dozens of targets on our Narrowband Expectation page, which I'm sure you will find interesting.
Stacked results from each filter, in order H > S > O
If you want to process your images the same way I do, you can get our full step-by-step processing workflow for nebulae, HERE. Included are 20 lessons, our process icons, our raw data, and 18 walkthrough videos. We also have a beginner version available that focuses more on RGB data. The nebula guide also includes a section on how to download and process data from the James Webb Space Telescope.
Dragons of Ara Nebula FAQ
In which constellation is the Rim Nebula located?
NGC 6188 is located in the constellation Ara.
How big is the Rim Nebula?
The Rim Nebula spans about 600 light-years across, and has an apparent size of 20x12 arcmin.
How far is the Rim Nebula?
The Rim Nebula is located about 4,000 light-years away from Earth.
How long should my exposure time be when photographing the NGC 6188?
For nebulae like this one, we recommend an exposure time of 300 to 600 seconds (5-10 minutes). We usually always shoot 10-minute exposures for nebulae with our f/5 refractor.
Should I use a filter to image the Fighting Dragons of Ara Nebula?
NGC 6188 is, as you saw above, rich in all three types of narrowband gasses. Because of that, it's a great idea to shoot this target with a monochrome camera and narrowband filters. You can also use a dual-band filter on a color camera. If imaging from a dark site, you should be okay with a DSLR camera or an OSC camera without filters, but it will not give you the absolute best results.
What equipment do I need to photograph the Rim Nebula?
A small telescope (300-500mm in focal length) is good to capture a wide-field view of NGC 6188. A telescope with a long focal length (1000mm or more) will get you a nice close-up view of either the Fighting Dragons or the Dragon's Egg nebula.
What type of nebula is the Fighting Dragons of Ara Nebula?
NGC 6188 is an emission nebula.
Final Thoughts
The Rim Nebula is one of the most exciting southern targets in the sky! It is large, colorful, and appears beautiful no matter which telescope is used to capture it.
If you do not have access to southern skies and would like to process this target, give Telescope Live a try and use the code TL4GH if you would like to get a discount!
Have you captured the Rim Nebula? If so, add your pic to the comments section, we'd love to see it!
Clear Skies,
Galactic Hunter
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