Here are some screenshots for comparison: I am using KSP version 1.3.1
I'm not able to upload images here, So please refer this link: https://imgur.com/a/nQ0FJ2T,
Not only those planets but moons as well, textures in the map mode looks fine but when in game mode it looks pixelated blurred and not clear. This problem persists in both the texture packs 4k and 2k. I tried with 4k first, but same problem, then I replaced it with 2k thinking my laptop is not supporting 4k, again same problem. The hardware is compatible.
So what is the issue? Also before installing all the other mods unrelated to Astronomer's visual pack I tested it once but, same problem. Please tell me how to fix it?
EDIT: Kerbin looks just fine both in Map and game modes, Problem is with only other planets. AND I used CKAN to install mods.