def rprojs(self):
        """
        Return the projected (in xy/uv plane) radius of each element (either
        vertices or centers depending on the setting in the mesh) with respect
        to the center of the star.

        NOTE: unscaled

        (ComputedColumn)
        """
        # TODO: should this be moved to Mesh?  Even though its surely possible
        # to compute without being placed in orbit, projecting in x,y doesn't
        # make much sense without LOS orientation.
        rprojs = np.linalg.norm(self.coords_for_computations[:,:2], axis=1)
        return ComputedColumn(self, rprojs)