Completed!
Instructions

The goal is to position two stars in each row, each column and each box.

Stars may not be adjacent in any direction.

Click or tap to place a star or to remove it. Forbidden boxes will be shaded automatically.

Boxes can also be shaded by a right-click or long press. Repeat to remove the shading. This is just to help visualise where stars probably can't go.

These puzzles have been taken from the Puzzler Collection magazines and are probably in breach of copyright even though the page is for private use, so please don't share it.

1
2
3
471/146
4
471/147
5
6
7
480/158
8
480/159
9
481/89
10
481/146
11
485/158
12
485/159
13
662/40