Angular resolution of the Pachmarhi array of Čerenkov telescopes

The Pachmarhi array of Čerenkov telescopes consists of a distributed array of 25 telescopes that are used to sample the atmospheric Čerenkov photon showers. Each telescope consists of seven parabolic mirrors each viewed by a single photo-multiplier tube (PMT). Reconstruction of photon showers are carried out using fast timing information on the arrival of pulses at each PMT. The shower front is fitted to a plane and the direction of arrival of primary particle initiating the shower is obtained. The error in the determination of the arrival direction of the primary has been estimated using the split array method. It is found to be ∼2.4′ for primaries of energy>3 TeV. The dependence of the angular resolution on the separation between the telescopes and the number of detectors are also obtained from the data.