Stacking in astrophotography is the superimposition of several images. The images were all taken with the same settings. Nevertheless, each image has a different level of noise. Software such as Sequator now reduces the noise by calculating all these images.
Stacking astro images should produce images with significantly less noise and create detailed star images even with shorter exposure times. This way you can get more detailed images with Sequator. I have used this technique several times and am very satisfied with the method. Optimizing astro images with the stacking method requires taking several identical images of the astro scene. It is best to take at least 10 images. Download the free Sequator software for Windows.
Add your captured images in .tif format using the Add button.
For the base image, select the image with the highest resolution of the foreground. This image is used by the software as the basis for the landscape without the starry sky. For the noise image, you can select an image with the lens cap in place to remove the hot pixels.
Select the "Irregular Mask" under Sky-Region and use the tool to select the landscape (green color) with the left mouse button. The selection wheel adjusts the size of the selection and you can delete it again with the right mouse button.
You have several settings to choose from in the Composition tab. You can even create star trails, among other things. I select the Align stars and Accumulation options here to optimize the noise. To fix the foreground (the landscape), I set it to Freeze Ground.
After entering the name for the output file - Output, the image can be calculated via Start. Depending on your satisfaction, you can generate better results in the settings via Auto Brightness or High Dynamic Range, for example.
I think the comparison is very clear. You can see much less noise on the right-hand image (stacked image) than on the left-hand image (not stacked). That’s why I always try to take a larger number of pictures to make them more detailed and less noisy.
If you want to go one step further, consider buying a Star Tracker.
My tip for a Star Tracker (advertising).
