Photoshop :: Adjust Pivot Center Of Object To Anywhere In Space?

Inside 3D Studio max, its possible to adjust the pivot center of an object to anywhere in space. So if for example, I've got a sphere in my scene and I want to have a bunch of cones spin around the center of the sphere (to create the basic shape of a sun graphic) I can just change the cone's pivot to be in the exact center of the sphere and then when I rotate and copy the cone, they will all be perfectly centered around the sphere.
 
Tying to do this in Photoshop however is proving rather difficult. Since the triangle representing the sun's rays is smaller than the circle representing the sun, I can't move the traingle's pivot to match the center of the sun because the bounding box for the transform isnt  big enough.

If I duplicate the sun and merge the triangle and the sun together, the merge action re-adjusts the pivot to be in the center of both objects so its no longer in the correct center of the circle. I can however move the pivot point to the approximate location now because the bounding box is larger, but I don't need the approximate location, I need the exact location.
 
Is there a way to move the pivot to a specific coordinate? Or am I going to have to move everything onto a perfectly square canvas and snap everything to grid lines?