Wide field aplanatic two-mirror telescopes for ground-based γ-ray astronomy

Aplanatic telescopes with two aspheric mirrors, configured to correct spherical and coma aberrations, are considered for application in γ-ray astronomy utilizing the ground-based atmospheric Cherenkov technique. We explore the phase space of optical system parameters to find telescope configurations which minmize astigmatism. It is shown that unlike the traditional prime-focus Davies-Cotton design, such telescopes provide a solution for wide field of view γ-ray observations. The designs are isochronous, can be optimized to have no vignetting across the field, and allow for significant reduction of the plate scale, making them compatible with finely-pixilated cameras, which can be constructed from modern, cost-effective image sensors such as multi-anode PMTs, SiPMs, or image intensifiers.