I’ve been serious astrophotography for about 20 years. I started in Seattle (a big mistake), but now, I’m in Arizona, where we have a lot of “clear sky” nights.
I use a small, portable wide-field telescope, and I have a home observatory that houses a 12-inch lens designed just for photography.
Stargazers know that you can spend hours getting a good picture of a galaxy or nebula. The light emitted by these distant objects is very faint, so it will be a while before those photons overlap.
There are several programs dedicated to astrophotography. PixInsight is a great example. I think it has slowly drawn astrophotography photographers away from Photoshop, but it has a huge learning curve and many photographers who have spent a lot of time using Photoshop can stay with Adobe.
One of the things that makes Photoshop so much easier to use in astrophotography is a series of plug-ins by Russell Croman, a former engineer, chip designer and professional software expert, who put those software skills to use creating plug-ins that don’t work with anything other than astrophotography. The plug-ins have become so popular that he’s doing it full-time.
GradientXTerminator
I first bought a Croman plug-in around 2000. It’s called GradientXTerminator. It fixed a major problem for astrophysicists, which was gradient correction (uneven background). His solution was so nice and easy, I’m still using it 20 years later. It has gone through a lot of updates (all free so far) and it now supports my Apple Silicon computers.
This is a wide shot of the Veil Nebula, with lots of gradations and a particularly bright color in the center.
Fixing this is pretty simple. Open an image with an uneven background that is messing up your photo. Outline your image with the noose tool. Invert the selection so that you select the sky where the gradients will be.
Then, open the plug-in and choose how much you want Russell’s smart algorithms to use to fix gradients. On top of that, GradientXTerminator will color balance your images.
Here is the final result:
miniature stars
Croman wasn’t content to just deal with the gradient problem, so he went ahead with bulging stars. While the stars should ideally be precise points of light, our atmosphere and even the optics we choose could magnify the stars, drawing attention away from the object. image in your photo.
There are a number of filters built into Photoshop that can help with this, but you’re better off getting a filter designed specifically for bulging stars. That’s what Star Shrink does. You turn on the filter, then adjust the stars so that the smaller ones become precise highlights. You can adjust the radius of the stars and the intensity of the filter. In regions with a lot of stars, such as near the Veil Nebula, it can make a big difference. Unlike some built-in Photoshop solutions, it works on the entire image at once. So basically all the stars are dropped by one click.
Here is the Veil Nebula again with star reduction. It can help highlight the subject you’re working on and help reduce distracting stars.
NoiseXTerminator
Of course, noise is one of the biggest problems with astrophotography. You are shooting in very low light and there is always noise as a result.
Topaz and a few others have some great noise reduction plug-ins and I’ve used them on photos of the sky. But Croman told me he wanted something designed to combat noise in astrophotography, so he created his own plug-in.
As Croman says: “NoiseXTerminator is specifically trained in astrophotography in the deep sky, so its neural network is familiar with the shapes of stars and the types of details we see in images. It can do natural detail enhancement without increasing noise or inventing unnecessary things. structure exists.”
This is a close-up of NGC1977 in Orion. It’s an old image I made years ago and has a lot of noise.
Giving you a web-friendly JPEG isn’t the best way to see noise, but there is a lot of noise.
After running NoiseXTerminator everything is much cleaner.
While Topaz and other plug-ins work quite well, for astrophotography, Croman’s solution is more suitable.
star Xterminator
This plug-in is truly remarkable. Here’s Croman’s explanation:
StarXTerminator uses an advanced convolutional neural network with a unique architecture that is well-suited to this task. The network has been extensively trained on photographs from a variety of instruments, from camera lenses to the James Webb space telescope. Minor stars, massive stars, giant stars and even diffraction spikes are identified and eliminated, with minimal impact on non-stellar features.
I didn’t think it would be worth it, but it is. Nebula in particular is impressive without a stellar background, but StarXterminator is really valuable because it allows you to separate your stars and main object on different layers, allowing you to adjust the stars accordingly. to your liking while keeping the nebula or galaxy intact.
Here is my Veil Nebula again, but with the stars removed.
In general, I would save the stars and place them on another layer so that I can process both layers independently, but these starless objects are quite intriguing, although not exactly the same as the mode. their real world view.
Summary
If you’re using Photoshop for processing, I think some or all of Croman’s tools are a must. They can save you a lot of time and give you better results than you can get using Photoshop’s built-in tools alone. These Photoshop plug-ins also work with Related Photos, if that’s your choice to deal with.
They also work with the very complex PixInsight, and Croman has produced a PixInsight-only sharpening tool called BlurXTerminator, which is getting rave reviews.
Processing astronomical images is as difficult as image processing. Roman made a great contribution to the art and science of astrophotography.
His website is Thisand you can test each plug-in and buy any of them if you want.
