these are typically made by taking video of the planet or at least several hundred images. then a software (i use registax) will take the clear parts of the images, and stitches them together. this is because as you take an image of a planet, you see the atmosphere move and you'll have waves of blury, and spots of clear parts of every image you take. but if you take many pictures, different parts will be clear in each. and you can yust stitch them together to get one clear image. the effect of the atmosphere moving in the eyepiece and the planet kind of waving with it looks really cool. i once on a -20c winter night i tried to take images from my living room window, but the glass was in the way (i was mostly getting dirt on the glass instead of the planet). so i opened the window and the planet strated waving like i was lookig at it from under water.  i love this hobby.
Hungary