Mis à jour : 6 juil. 2020
One thing I have always dreamed of is to spend several nights on the same target and end up with an incredible image. This has always been impossible for us as we never had a backyard and had to image far from home every single time. Time being of the essence, we usually spent 4 hours on one target, then went home.
Now that we finally have a backyard, I decided to do start my first “long” project, and chose the Sadr Region to do so. Why? for a couple of reasons. It is one of the first targets to rise at the end of the Spring season and so I wouldn't have to stay up too late just to start imaging.
For this project, I used our small Meade 70mm APO Refractor telescope and our ZWO ASI 1600MM monochrome camera.
I wanted to use the small Meade because it allows me to carry the entire setup in and out of the house without having to unplug or de-attach anything! That made the job much easier.
The Sadr Region is very large and is full of gases that look great in narrowband. Living in the heart of Las Vegas, light pollution is as terrible as it gets in our backyard and the lights from the neighbors don’t help either, so I aimed for 40 hours of total exposure in HSO. I ended up with 41.15 hours in total.
The image shows the bright star Sadr (mag 2.2), and part of the "Sadr Region” that includes the Butterfly nebula. Known as IC 1318, the Sadr Region is located at the center of Cygnus’s cross asterism. We can see lots of interesting gas formation within the entire photograph.
The cropped image on the left shows the Butterfly Nebula only. The black area represents the body of the insect, and two large wings can be seen on each side.
The bright star near the right is Sadr.
We made a video about what it's like to image the same target for several weeks, make sure to watch it!
The Sadr Region from our Bortle 9 backyard in narrowband
Interested in a print? You can get one HERE!
Raw Data available on Patreon
Camera: ZWO ASI 1600MM
Telescope: Meade 70mm APO
Mount: Orion Atlas EQ-G
Guiding: ZWO ASI 290MM Mini
Acquisition: ZWO ASIAIR
Total Exposure Time: 41.15 hours
Exposure Time per frame: 5 minutes
Filters: Ha (236)/Sii (139)/Oiii (121)
How to find the Sadr Region?
The Sadr Region is extremely easy to find. It is located in Cygnus, one of the brightest constellations in the night sky, home to one of the three stars forming the "Summer Triangle": Deneb. As the name implies, the Sadr Region is a nebulous region around Sadr, a bright 2.2 magnitude star located at the center of the swan. Because Sadr is so easy to spot, you can simply aim your telescope at the star and take a long exposure image, preferably with a Hydrogen Alpha filter, to see lots and lots of gas.
As you can see in our picture above, we pretty much centered Sadr in the middle of our frame and slightly aimed a little bit higher to include the entire Butterfly Nebula.
Sadr is 150 times larger than our Sun's radius
The Butterfly Nebula shares its name with another Butterfly Nebula, NGC 6302
The Sadr region is surrounded by several clusters and nebulae
Processing of the Sadr Region
Processing IC 1318 was pretty difficult! First of all, I had to stack each channel individually or the computer would crash. Drizzling was also not fun and took many, many hours. Sometimes, the computer sounded like a rocket about to explode.
I wasn't happy until the results until I tried Steven Miller's processing workflow, which you can find HERE. This made such a huge difference and I want to thank Steven for making this tutorial so wonderful and easy to follow.
The channels were combined using the Hubble Palette (SHO). I had to reprocess the image several times as I was never pleased with the blues throughout the gases. At some point I decided to go way too crazy with the blue colors and ended up with a pretty interesting result, as seen below.
What did each narrowband channel look like?
Below you can see what each stacked frames looks like for the three narrowband channels. We used the following filters to capture IC 1318:
Hydrogen Alpha (left)
Sulfur II (center)
Oxygen III (right)
I was a little scared with the Oxygen data because Sadr looked completely blown out. Making this less obvious required some extensive post-processing in Lightroom.
Our video about capturing the Sadr Region from our backyard
If you'd like to learn more about how I photographed this area of the sky for several nights, watch the video below! I also show you the difference between a 5-minute frame taken from home vs one taken from a Bortle 3 desert spot. If you are scared of insects, know that there are some spiders in that video...
This was... an interesting project! It took a long, long time but I feel like it was worth it in the end. I only wonder how many hours would it have taken if I imaged it from the desert instead. My guess would be about 8 hours. Imaging from a very light polluted backyard requires lots and lots of frames to get rid of the noise, but we are glad we are able to image from home!
Would you like this image as print? You can purchase one on photo paper or metal HERE!
Have you captured the Sadr Region or the Butterfly Nebula? Attach your image in the comments and let us know your acquisition details!
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