I’ve been having quite the time figuring out how to properly calibrate the images from my big ass Newtonian. I think I might be getting somewhere! The first key was taking proper flats, which I will do a separate post on soon. Along with flats, you also need bias frames.… Continue Reading... "Preprocessing with Siril"
I started my first multi-night project in Siril. It was a little unintuitive on how to do this. First, you’ll want to create sequences for the data from each night, and then preprocess the files. Make sure these sequences have the same name. However, you want to index the files… Continue Reading... "Combining sequences in Siril"
You hear this advice everywhere you look when it comes to astro imaging. It’s pretty much true. Dithering is an event that occurs between exposures, where the mount is moved a little bit in a random way to point a few pixels away from where it just was. This is… Continue Reading... "Dither or Die"
I’ve been fighting a big problem recently with concentric rings of different colors appearing in both my lights and flats. However, the flats do not correct the rings in the lights, and possibly make them worse. Below is a severely stretched stack of over 60 images of M101 that were… Continue Reading... "Concentric coloured rings in images"
I finally noticed that after debaying my RAW images in Siril, the colors didn’t look right. With my modified DSLR, the images are definitely strongest in the red channel, but the debayered images did not match that. I fiddle with the settings for the program, and it now processes the… Continue Reading... "General settings in Siril for DSLR images"
If you have an uneven background in your image with a target that doesn’t take up most of the image, I have found a good method to remove it. My flats are sometimes not the best, probably due to the multiple pieces of glass I have between the telescope and… Continue Reading... "Effective background removal"
With the new denoise scheme and other skills under my belt, I’ve been redoing the post-processing of many of my older images, with much better results. As another example, here is the Crescent nebula: Steps taken to process this were the following: Levels adjustment to remove most of the background.… Continue Reading... "Retouching the Crescent"
I did some tests with the stacking settings in Siril, and then checking the noise values afterwards. Trying both average and median, along with the many rejection schemes and their settings, I have found the following settings to work best for me: The sigma rejection scheme seems to give me… Continue Reading... "Siril stacking settings"
Even after stacking dozens of subframes to reduce noise in an image, I would still have quite a good deal of luminance and color noise. Luminance noise is definitely the most distracting, and removing it without removing detail of approximately the same scale was very hard to do manually. After… Continue Reading... "The silver bullet for still noisy stacks"
Still experimenting with post-processing techniques, I made another attempt at the Triangulum. The subframes for this were extremely noisy, and the resulting stack was still quite noisy. The flats I took at the time were pretty poor and added some rotational gradients to the image. I decided to take a… Continue Reading... "Triangulum 2: Galactic Boogaloo"
