Pattern grid generated by projector to (a) allow for focusing during set-up and (b) to zoom the image to completely fill the screen. The projector provides a 16:9 image to match the 16:9 screen - A Stewart StudioTek 130 96" x 54" 110" diagonal screen with a 1.3 gain factor. The screen is operated by a wall switch and has been calibrated to lower to the exact same spot every time, keeping everything aligned. This is accomplished by limiting switches in the screen mechanism.
NOTE: The light flare in the picture is caused by the overhead lighting, not by the screen. Naturally, it's "lights out" during normal viewing.