Updated: Jul 13
XSS J16271-2423, better known as Rho Ophiuchi, lies at a distance of about 400 light-years from us. It is a binary star system and the closest stellar nursery to Earth. It surrounds the huge orange star Antares.
Because of its size, you will not need to capture this target with a telescope. The challenge is to get as much nebulosity as possible without the bright stars being blown out. Rho Ophiuchi is an excellent widefield Astrophotography target for DSLR camera users of all levels!
Object Designation: XSS J16271-2423
Also known as: Rho Ophiuchi
Object Type: Cloud Complex
Distance: 400 light-years away
Discovered in: Unknown
Be sure to photograph Rho Ophiuchi when it is high enough in the sky, which is not for long. If not, your image will be affected by atmospheric turbulence and/or light pollution from the light domes of nearby cities.
We suggest spending at least a couple of hours on this target, although we got some nice results with just 40 minutes of total exposure with an unmodified DSLR camera.
Below you will find all our attempts at capturing Rho Ophiuchi, from newest to oldest:
Rho Ophiuchi mosaic with a RASA8 - 2023 - 8 hours of exposures
Rho Ophiuchi with a 135mm lens - 2021 - 3 hours of exposures
Rho Ophiuchi with a 50mm lens - 2020 - 2.5 hours of exposures
Rho Ophiuchi with a 50mm lens - 2019 - 40 minutes of exposures
Rho Ophiuchi Mosaic with a RASA 8 from a Dark Site
This is a shot I've been dying to get for years: A close-up view of Rho Ophiuchi in very high definition! For the first time in my astrophotography journey, I decided to do a mosaic, which allowed me to get as much detail as possible on my target. I had only done one mosaic before, the one with Planet Mars and the "Green Comet", but that was only two panels and there wasn't really any challenge there.
The picture you see below is a 4-panel mosaic, taken with our RASA 8 f/2 telescope from the Bortle 2 skies of Utah Desert Remote Observatories. I spent approximately 2 hours on each panel, which was enough thanks to the fast optics and clean sky.
We absolutely love UDRO, as it allows us to image on every single clear night without having to drive far from home and set up our equipment each time. It saves us sleep, gas money, and time. If you'd like to have your telescope next to ours at this remote observatory, be sure to email the owner Craig from the website!
On the left is a picture of me with the rig that took the image of Rho Ophiuchi.
Creating the mosaic and processing was done in PixInsight, and was a lot of fun, There were some leftover lines from the stitching which I did my best to hide, and the end result looks nice.
Camera: ZWO ASI2600MC
Telescope: Celestron RASA 8
Mount: 10Micron GM1000 HPS
Guiding: ZWO ASI 290MM Mini
Total Exposure Time: 8 hours
Exposure Time per frame: 5 minutes
Rho Ophiuchi with a DSLR and 135mm lens at f/2
First light with the Samyang 135mm f/2! 🥳
I’ve been wanting to capture Rho Ophiuchi up close since imaging this object with the 50mm lens (scroll down to see it!). The smallest telescope we have, the Askar FRA500, would be great if using our full-frame camera, but it would be a tiny bit too tight! Because of that, I recently bought a 135mm f/2 lens, just so I could get a closer view of Rho Ophiuchi.
I have to say, I was blown away by how crisp the stars were all over the field of view even with the aperture wide open, wow! The image below was taken at f/2!
I spent the night with my good friend Avedis, we had a few drinks annnnd I completely messed up my framing when changing the battery at 1 AM 😅 So this is about 3 hours on Rho Ophiuchi at f/2 from a Bortle 2 zone.
I am happy with the results, although I wish I used an auto-guider because the stars do look a tiny bit elongated when zoomed in. Make sure to watch the video I made about this night!
Camera: Canon Ra
Lens: Samyang 135mm f/2
Mount: Atlas EQ-G
Total Exposure Time: 3 hours
Exposure Time per frame: 3 minutes
Tip: Doing 3-minute exposures at ISO 1600 was a little bit overkill at f/2! The histogram curve was a little bit too much to the right, near the middle of the histogram display.
This means that technically, the shots were all a bit too overexposed, but I kept going anyway without reducing the ISO. Bringing the ISO down to 800 would have pushed the histogram to the left, into the "sweet zone", but having your images a tiny bit on the edge of being over-exposed is not a bad thing when imaging from a dark site.
The image above shows what a single 3-minute shot looked like straight out of the camera. Under Bortle 2 skies, there isn't really any noise coming from light pollution and so it is completely safe to keep imaging with the histogram in the middle.
Rho Ophiuchi by the James Webb Space Telescope
A tiny section of the Rho Ophiuchi molecular cloud complex was captured by the James Webb Space Telescope. The image was released on July 12, 2023, and looks absolutely beautiful as you can see below!
This small part of the target shows several bright stars, and interacting gas formations. The NIRcam instrument on board of the JWST captured this target using 5 different filters: F187N, F200W, F335W, F444W, and F470N.
Did you know that you can see this in our mosaic image? Go ahead and look for it, it's actually almost dead in the center of the frame!
If you need help finding it, check out the comparison image we made below, showing our wide field shot with a DSLR, our mosaic image, and JWST's version.
Rho Ophiuchi with a 50mm lens: 2020 attempt
Do you notice a weird blue-ish shape above the Rho Ophiuchi cloud complex in the image below? This is a rarely photographed nebula called the Blue Horsehead Nebula! Make sure to check out our full blog post about it.
2.5 hours on Rho Ophiuchi with a Canon 5D Mark II
Camera: Canon 5D Mark II
Total Exposure Time: 2 hours and 30 minutes
Exposure Time per frame: 30 seconds
300 lights, no Darks and Bias
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Rho Ophiuchi with a 50mm lens: 2019 Attempt
40 minutes on Rho Ophiuchi with a Canon 70D
Camera: Canon 70D
Mount: Omegon Mini Track LX2
Total Exposure Time: 40 minutes
Exposure Time per frame: 1 minute
40 lights, calibrated with Darks and Bias
Huge thanks to Benny Johnson for lending us his DSLR camera and allowing us to get this beautiful image! That night, we reviewed the Omegon Mini Track LX2 tracker and chose to image Rho Ophiuchi. You can see our review video below!
How to find Rho Ophiuchi?
Rho Ophiuchi is huge and hard to miss, as it covers an angular area of 4.5° × 6.5° in the night sky! For comparison, the full moon is about 0.5°. Because of that, you shouldn't bother aiming a telescope to this target, unless you want a nice view of the Antares.
Rho Ophiuchi is one of the easiest targets to locate out there. To find it, look for its bright orange star Antares, which is also the brightest star in the constellation Scorpius and the most orange star in the entire Summer sky.
Pointing your camera at Antares assures that you will capture most of Rho Ophiuchi, as Antares lies within the complex. All you have to do next is to frame the view to your liking. If using a 50mm lens, like us, you can capture some of the Milky Way band on one side of your image while still keeping Rho Ophiuchi visible.
Cool Facts about Rho Ophiuchi
Consists of 2 major regions of gas and dust
Temperatures within the clouds range from13K to 22K
Good to photograph with Saturn if present
Single Shot & Processing of Rho Ophiuchi
Processing Rho Ophiuchi can be a bit tricky, especially for people who have never processed such wide-field targets in the past. The processing techniques used for Rho Ophiuchi are closer to those used for Milky Way shots than galaxies, nebulae, or other deep-sky objects.
Below is a single shot of one minute of Rho Ophiuchi. It is pretty difficult to see any details, but we can easily make out the Orange star Antares and the surrounding bright stars, as well as a faint Milky Way band. Jupiter is also impossible to miss in this example, but the planet might not be in your frame when you image this area of the sky yourself.
You can get our full PixInsight workflow "follow along" HERE.
Single shot of Rho Ophiuchi, 1 minute of exposure
The Milky Way now appears obvious when stacking several frames together. Below is what we got out of PixInsight when stacking 40 frames of one minute each together, for a total of 40 minutes only! The dark, cloudy "tails" that come out of the Rho Ophiuchi cloud complex can now also be seen pretty easily.
All 40 single shots stacked together - 40 minutes total
Our Full Review of the Omegon MiniTrack LX2
In order to take 60-second long exposures with our 50mm lens, we had no choice but to use a device to track the sky. We could have used our trusty Atlas EQ-G motorized mount, but why carry such a bulky piece of equipment when we could use a small and lightweight star tracker?
You can find our full video review of this fantastic tracker below, or check out our written review by clicking HERE.
Rho Ophiuchi is a great target to photograph on a night when you don't want to bring your telescope out. This is a beautiful object for DSLR camera users, and you can get some acceptable results with just 40 minutes of total exposure! Adding more will of course make the nearby Milky Way band brighter and more defined. You will also see more gas around Rho Ophiuchi itself.
If you are able to spend several hours imaging Rho Ophiuchi, you should notice lots of faint gases and beautiful colors popping out in your final result. A dark sky far from light pollution is of course ideal for this wide target and will help tremendously in reducing noise.