Rho Ophiuchi - Widefield Photography of our closest Stellar Nursery

Updated: Apr 28


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!


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 exposures with an unmodified DSLR camera.


Below is our latest attempt at capturing Rho Ophiuchi, with a total of 2 hours and thirty minutes of exposure. Scroll down to see our previous result with only 40 minutes, doing 60-seconds exposures at 50mm and tracking the sky with the Omegon Mini Track LX2.


Latest Attempt: Rho Ophiuchi in 2020

2.5 hours on Rho Ophiuchi with a Canon 5D Mark II

GEAR USED:

Camera: Canon 5D Mark II

Lens: Canon EF 50mm f/1.8 STM Lens

Mount: Sky-Watcher Star Adventurer Pro

Processing: Pixinsight

ACQUISITION DETAILS:

Total Exposure Time: 2 hours and 30 minutes

Exposure Time per frame: 30 seconds

300 lights, no Darks and Bias

ISO: 800




Rho Ophiuchi: 2019 Attempt

40 minutes on Rho Ophiuchi with a Canon 70D


GEAR USED:

Camera: Canon 70D

Lens: Canon EF 50mm f/1.8 STM Lens

Mount: Omegon Mini Track LX2

Processing: Pixinsight

ACQUISITION DETAILS:

Total Exposure Time: 40 minutes

Exposure Time per frame: 1 minute

40 lights, calibrated with Darks and Bias

ISO: 800


Huge thanks to Benny Johnson for lending us his DSLR camera and allowing us to get this beautiful image!


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 target 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 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
  • 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 fo 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 as a PDF "follow along" file 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.




Final Thoughts

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 great 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.



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Clear Skies,

Galactic Hunter





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