Rotating 2D Camera

I have a layer of size 7680 * 4320. There is a planet in the center of the layer. Now imagine the layer being divided into four quadrants of equal size. What I want is that the user is able to see only one quadrant at a time with the center planet at the bottom left. If the user wants to view another quadrant however, the entire layer is rotated so that the center planet still remains at the bottom left.
The first thing I tried was rotating the layer itself which worked, but then I added projectiles (and this center planet acts as the main source of gravity) and when I rotate the screen, the projectiles start moving in the wrong way (because of change in transformation matrix and hence force applied towards center). So next, I tried changing the camera instead. The only problem is, the camera always rotate in the center, even if i set the anchor point to (0,0).

Anybody has any solution to what I am trying to achieve here!? How can I rotate the camera around the center planet which is at (0,0) of the world. Or how can I rotate the layer without affecting the force applied on the projectiles (which requires their current position)