A procedure is proposed that, given any rotating device to support a camera, places the camera's center of projection to within a tenth of a millimeter from the axis of the rotating device, even with wide angle lenses with severe distortion. Results are experimentally validated by checking that all the camera projection centers as computed through an off-the-shelf calibration method are at the same point in the world, and that the camera rotations computed by the same calibration method are close to the true values measured with a mechanical, high accuracy positioning jig. Experimental data and Matlab code are accessible on the worldwide web.