"In this paper we demonstrate a new technique in which we use the three parallel laser
beams alignment device and the CCD camera to rapidly and accurately align the optical axis of an
off-axis parabolic (OAP) mirror. In this method the optical axis of an OAP mirror is made parallel
to the “three incident laser beams” in the plane of incidence, by checking direction of these three
reflected laser beams and changing the height and orientation of the OAP mirror. This fast
aligning method for finding the optical axis of an OAP mirror can measure the Slant Focal Length
deviation to an accuracy of 0.2％ ."
