A 15° wide field of view imaging air Cherenkov telescope

Abstract

Contemporary imaging air Cherenkov telescopes (IACT) for ground-based very high energy (VHE) gamma-ray astronomy have prime focus optical design. Typically, these telescopes have a (2–4)° wide field of view (FoV). They use F/0.7– F/1.2 optics and provide (3–10)′ resolution in the FoV. Generally, a well designed telescope that includes more than one optical element will offer some advantages not available in prime focus designs, such as a wider FoV, a more compact size, a higher and more homogeneous resolution and a lower degree of isochronous distortion of light rays focused onto the focal plane. Also, they allow monitoring the gamma-ray activity in a sizeable portion of the sky in a single observation. This would allow one to perform a sensitive all-sky survey in a relative short time. We present an F/0.8 15° wide FoV telescope design, which provides a high and near uniform resolution and low isochronous distortion across the entire FoV.