Since I personally had a lot of trouble with finding all of Margoria's Star knowledge locations I made overlay so you can use software like OnTopReplica to put the overlay on top of your screen with 50% opacity and see exactly where you need to be, make sure to enable Advanced -> Enable Click-Through.

Keep in mind the location of NPC that gives knowledge is a little bit off like this.

For overlay to work set your world map to 90 degrees in settings, and resolution to 1920x1080 Full Screen Window.

If you want to see how knowledge location looks on minimap watch this