If you already have position keyframes for the drawing then moving the anchor point will mess up your animation. You could place a 3D null object in the center of your layer, then parent the layer to the null, then rotate the null.
One way to place the null at the exact layer’s position at the exact time you want it to spin is to create the null, make it 3d, drag the null’s parent pick whip to the sun layer. Type 0 (zero) in all position, rotation, orientation values of the null, then unparent it. Select “Local Axis mode” then drag the x and y axes to the center of your layer. If the anchor point z position of your layer is not 0 for some reason, then you’ll have to take the negative value of the z coordinate to zero that out. Then parent the layer to the null and keyframe the null rotation values. This makes it better than just guessing where your layer is in 3D.
Kind of convoluted, but I use this process all the time.
Dan Fredley