~600 images with 4 seconds exposure without a tracker. This is my first ever (successful) try of any object on the night sky. I did a post a few weeks ago asking for a camera setup, and I went and bought a panasonic lumix g85 with the 45-150 f4-5.6 lens I had in mind before that. I know this is not the ideal setup, but I am still very proud of that image. Although I would appreciate any feedback on how to improve my skills.
Those star trails look longer than you would get from 4 second exposures, so I suspect you could do even better with more careful processing. Good start, though!
But the star trails are similar sized in the raw files. I used Siril to stack and had to set the roundness value to around 0.3 for it to register the stars. I saw a yputube fix for that. The guy also set the Relax PSF thing to true, maybe this made them not perfectly aligned?
Then it’s a problem with how you’re taking the images. Maybe the system is physically moving when you take the image?