The Twin Quasar - A Rare Astrophotography Target Showing Gravitational Lensing
Updated: May 18, 2023
The Twin Quasar is a quasar in the constellation Ursa Major that appears as two distinct quasars due to gravitational lensing. This is a mind-boggling object that is faint, extremely far away, and rarely photographed by amateur astrophotographers.
I captured the Twin Quasar on a full moon night from a Bortle 4 zone using a One-Shot-Color camera and a refractor telescope. In this post, you will learn all about the Twin Quasar, why it is such an interesting object, and how it made history.
Make sure to also watch our video on YouTube where you can see how I photographed this object from beginning to end!
Object Designation: QSO 0957+561
Also known as: Twin Quasar / Double Quasar
Constellation: Ursa Major
Object Type: Quasar
Distance: 8.7 billion light-years away
Magnitude: 16.7
Discovered in: 1979
The photo on the left was taken by NASA and shows a deep view of the Twin Quasar (the two bright blue dots with diffraction spikes).
You might be able to spot a yellowish galaxy in between the two, this is a giant elliptical galaxy known as YGKOW G1 which is believed to be the main contributor to the gravitational lensing effect.
This galaxy is part of a cluster of several galaxies which also affect the lensing.
Gravitational lensing effects are not very common and aren't really impressive in any way when imaged with amateur equipment.
On the other hand, they are often incredibly beautiful occurrences when captured by professional telescopes, like the Hubble Space Telescope.
The image on the right shows SDSS J1038+4849 (or "Cheshire Cat), a galaxy cluster in Ursa Major that is famous for looking like a space Smiley Face.
Here, the source of the gravitational lensing is perfectly aligned between the cluster and Earth, giving us a ring around the object, known as an "Einstein Ring". We'd love to attempt imaging this object when we get a large telescope someday :)
Below is our image of the Twin Quasar, annotated so that you can easily see where it is in the image! Scroll down a little more to see the full uncropped image.
NGC 3079 and the Twin Quasar - Annotated
GEAR USED:
Camera: QHY600C
Telescope: Stellarvue SVX130
Mount: Astro-Physics Mach1
Guiding: ZWO ASI 290MM Mini
Accessories: Moonlite Nitecrawler focuser
Processing: Pixinsight
ACQUISITION DETAILS:
Total Exposure Time: 5 hours
Exposure Time per frame: 5 minutes
Filters: N/A
Gain: 26
...And here is the full image. Difficult to spot the Double Quasar, isn't it?
How to Find the Twin Quasar
The Twin Quasar can be found in the constellation of the big bear: Ursa Major. It is obviously tiny and impossible to spot with the naked eye or any amateur instrument (although I now wonder if you could spot it with a long focal-length telescope under very dark skies... let us know in the comments!).
The easiest way to image the Twin Quasar is to slew your telescope to the nearest large galaxy, NGC 3079. From there, you will almost certainly include the Twin Quasar in your frame unless you are using a really large telescope. Compare your framing with our images in this post to ensure you got it in there!
Processing the Twin Quasar
This was a difficult target to process, mostly because it is just so tiny! If you are using a small or medium-sized telescope like us, know that it will definitely be difficult to bring out the two dots individually. A great camera with a high resolution is required so that both dots of light can appear separated.
Something you will absolutely need to do as well is to go through all your frames one by one (using Blink for example) and delete any that is not 100% crisp. Although it is tempting to keep most of your frames, I imaged this object during a windy night and so I personally deleted about 40% of all the shots I had because many of them were not perfect.
Besides that, you'll want to make sure to keep a preview window ready on just the twin quasar during your entire processing workflow. Check on that preview every time you apply a new process, and revert the process if the two dots were affected in a bad way (for example: became blurry during a noise reduction process...)
Learn how to process photos as we do by purchasing our PixInsight Processing Workflow.
Capture the Twin Quasar with Amateur Equipment
Below you can watch the video on our channel about imaging the Twin Quasar with an amateur telescope and camera!
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Final Thoughts
The Twin Quasar may not be the most impressive or most beautiful object out there, but it definitely is a great challenge! It is nice to know that it is possible to capture with amateur equipment, and to learn that this very object has a history in the world of astronomy as the first object where gravitational lensing was proven!
Have you captured the Twin Quasar? Attach your image in the comments and let us know your acquisition details!
Clear Skies,
Galactic Hunter
