Detailed simulations of a small-sized telescope with secondary optics for the Cherenkov Telescope Array, and for the first time, an attempt to show a comprehensive tolerance analysis of a Schwarzschild–Couder Cherenkov telescope.

The radius of the encircled point spread function (Θ₈₀) for the ideal optical system is found to be approximately 1.3 arcmin for an on-axis observation and approximately 3.6 arcmin for an off-axis observation at the edge of the field of view.

Shadowing is found to be at a similar level (∼11%) to that seen with the current generation of conventional Davies–Cotton Cherenkov telescopes.

An extensive tolerance analysis highlights the importance of maintaining the correct separation distance between the secondary mirror and the focal plane in order to contain the Θ₈₀ parameter within the size of a single pixel.

A small circular area (radius < 150 mm) at the center of the secondary mirror can be used for calibration and alignment instrumentation.