Schwarzschild-type aplanatic telescopes with two aspheric mirrors, configured to correct spherical and coma aberrations, are considered for application in gamma-ray astronomy utilizing the ground-based atmospheric Cherenkov technique. We use analytic
al descriptions for the figures of primary and secondary mirrors and, by means of numerical ray-tracing, we find telescope configurations which minimize astigmatism and maximize effective light collecting area. It is shown that unlike the traditional prime-focus Davies-Cotton design, such telescopes provide a solution for wide field of view gamma-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.
We present simulations of a large array of imaging atmospheric Cherenkov telescopes (IACTs), for which the size of the array footprint is much larger than the size of the Cherenkov lightpool. To evaluate limitations of the imaging atmospheric Cherenk
ov technique, the array is simulated under the assumption of ideal optics, having infinite resolution of the photon arrival direction, which makes our conclusions independent of any particular telescope implementation. The primary characteristics of the array performance, gamma-ray trigger efficiency, photon energy at the peak of the detection rate, and angular resolution are calculated as a function of the parameters of the array: telescope spacing, telescope aperture, and camera pixelation. We discuss implication of the results for the design of the next generation ground-based gamma-ray observatory.
