I recently ran an impromptu astrophotography image processing challenge, and the results were out of this world (sorry, I had to do it). The craziest thing about it is that the data wasn’t overly great (in terms of overall exposure time) or interesting. Just a seemingly random portion of the constellation Cygnus that includes the Tulip Nebula.
I posted the challenge on Facebook, with instructions to grab my backyard image data from this website’s ‘practice image data‘ section. I expected a few die-hard fans to post their results, but I certainly didn’t expect over 40 entries. I also didn’t expect them to be so good.
My example image of the data (processed by me) was humbly outdone, one after the other, in the post’s comments section. In fact, if I had to rank my version of the image against all of the submissions, it would land in the bottom 5. But you know what, I learned why the best images looked so good, thanks to the detailed image processing notes.
The image was captured using an Askar SQA55 refractor telescope from my backyard.
The Top 4 Results
It wasn’t easy, but I narrowed down the top 4 images. While a lot of ‘what makes a great astrophotography image‘ comes down to personal artistic taste, these submissions went above and beyond what I thought was possible with the data. Not only that, but what they did with it was thoughtfully controlled.
Thankfully, I have learned how to largely take the pressure off myself when making these tough decisions. You make the fans vote. I commented with the four names you see in the image below, and simply asked my Facebook audience to ‘like’ the name of the image they liked most.
4 images rose to the top of the processing challenge results.
You may have noticed a common theme in these images. They managed to pull the faint OIII (shown in blue tones) elements in this region forward, to balance the image. As this area of Cygnus is dominated by bright, hydrogen gas, the delicate blue oxygen wavelengths can quickly get overwhelmed (as you previously saw in my process of the data).
After seeing these results, I immediately went back to my image processing software (mostly Adobe Photoshop) to start playing with the OIII channel, in a desperate attempt to recreate what I was seeing. It turns out that an incredibly handy PixInsight script known as ‘DBXtract‘ was used to separate the Ha from the OIII. Bingo.
Overall Winner
I think you’ll agree that the image has a lot of depth and that the color palette is beautiful. If you need more convincing, go ahead and take a good look at that Tulip Nebula. I had no idea such an image was possible with this lackluster data! Congratulations, Thomas Rider, for your talented work, and for making me aware of an incredible new processing script!
As anyone who has used PixInsight knows, powerful tools don’t automatically mean great results. The art of image processing is involved, time-consuming, and rewards those with an artistic eye. Clearly, Thomas has a great feel for the tools in his routine and knows how to deploy them on challenging projects. Well done, sir!
The Tulip Nebula and Surrounding Area. Processing by Thomas Rider.
Thomas’ processing notes:
- I removed the gradient with background extractor then removed the stars with StarXterminator.
- Following that, I used DBxtract to separate the Ha from the Oiii.
- Found quite a bit of noise which is expected with such little integration time.
- Used BlurXterminator to try to clean up the Ha and Oiii.
- Performed linear fit after seeing how much brighter the OIII was when creating an HOO image with channel combination.
- Seeing the other post, I didn’t see anyone try to push the OIII, so I went for it, but could not push the data too hard.
- Tried to bring out some yellows and a couple different levels of red to create (to me) a more interesting color combo than the traditional Red/Purple of HOO using Selective Color Correction.
- Played with that and adjusted the colors until I was ok with it. Threw in some other bits to try to bring some texture and depth to the image.
- Although the stars were tiny, I reduced them anyway to try to push the nebula more.
- I’ve never processed this nebula before, but would love to get about 20-30 hours on it and some Sii data and see how far it can be pushed.
As for the DBextract script, I will continue to experiment with it. I have a feeling that it will be an extremely handy tool for images taken with my dual narrowband filters. If you have successfully installed and used this script on your images, please let me know how it went in the comments.
Trevor Jones is an astrophotographer and a valued member of the RASC. His passion is inspiring others to start their astrophotography journey on YouTube so they can appreciate the night sky as much as he does. His images have been featured in astronomy books & online publications, including the NASA Astronomy Picture of the Day (APOD).
Related Content:
