This paper describes the absolute phasing of two adjacent mirror panels using a 10 W tungsten lamp, a slit, a linear charge-coupled device array, and an oscilloscope. Repeatability of measurement settings equivalent to five one-thousandths of a wavelength was demonstrated using only visual observation of the oscilloscope and a calibrated phase changer. The indicator of phase used in these tests is the intensity distribution across the image, similar in this respect to the Phasar method developed by the Air Force Weapons Laboratory. The phasing of circular apertures as well as small subapertures is shown. A simple near-linear phase changer, to change phase manually by less than one thousandth of a wave, was developed to determine precision and accuracy of the phasing method.