I give the results of a study for the optical design of wavefront sensors proposed for the Gemini 8-meter telescopes. The sensors are to provide information for wavefront profiles at various resolutions, including 20 X 20 points over the pupil and 4 X 4 points over the pupil. They include the tip-tilt (star tracking) system. Points discussed include: the use of off-axis sensors; following the curved focal surface in the telescope; methods for varying the resolution in the pupil; reproducibility injecting a point source of light for checking and calibration; methods of finding the positions of the sub- apertures in the whole aperture; and methods of switching to a wider or narrower field of view.
Richard G. Bingham,
"Optics for wavefront sensors on the Gemini 8-m telescopes", Proc. SPIE 2774, Design and Engineering of Optical Systems, (23 August 1996); doi: 10.1117/12.246689; https://doi.org/10.1117/12.246689