Pachmarhi array of Cerenkov telescopes

Abstract

Pachmarhi Array of Cerenkov Telescopes (PACT) consisting of 25 telescopes has been installed at Pachmarhi (longitude : 76d 26' E, latitude : 22d 28' N and altitude : 1075m) recently. The telescopes are deployed in the form of a 5 - 5 matrix spread over an area of 80m - 100m. The array is designed to detect celestial TeV gamma-rays by wavefront sampling technique as against the standard imaging technique used at other ?-ray observatories elsewhere in the world. Each telescope consists of 7 parabolic reflectors of 90 cm diameter and an f/d ~1. Each telescope is independently steerable on separate equatorial mounts operated through a computer based control system capable of orienting them with an angular accuracy better than 0.2d. The pointing is monitored in real time to maintain a source tracking accuracy of better than 0.1d. We will discuss the array design, its suitability for wavefront sampling and its pointing capabilities.