A shaped pupil for a backyard telescope

Dr. Russ Genet at Cal Poly does speckle interferometry observations of binary stars. He came up with the idea to use a shaped pupil to improve the search zone around his primaries, and increase the kinds of targets accessible to his small telescope observing program. Our team agreed it would be an interesting experiment to see what shaped pupils can do for seeing-limited observations of binary stars.
I wrote some 2-D optimization programs (making yet more use out of the approach of Carlotti et al 2013) to come up with a design for Russ’ 11-inch Schmidt-Cassegrain pupil. There was one solution with a fairly simple layout. It improves the open aperture telescope PSF by suppressing the first sidelobe along one axis, as shown in the horizontal contrast cut plot below.C11_SP_12wa60_logc27_bowtie90degC11_contrast_cut_12wa60_logc27_bowtie90degIf Russ and his observing team, led by Cal Poly Master’s student Ed Foley, can freeze out the atmosphere and limit static aberrations, then they have a shot of effectively (almost) doubling the aperture of their Celestron setup.