A Pulsar Experiment—Our Experiences in Time Keeping

Abstract

Our group has been operating over the past five years at Ootacamund, a parabolic mirror array to detect Atmospheric Cerenkov Radiation signals induced by pulsed high-energy (≳200 GeV) gamma ray emission by pulsars. Though the experiment calls for very accurate time-keeping necessitating the use of an atomic clock, we did not have one. We have overcome this difficulty by using a temperature-controlled crystal oscillator with frequent calibrations by signals received by telephone from a nearby atomic clock and by radio from ATA (National Physical Laboratory) broadcast. Relevance of accurate time-keeping to pulsar research is outlined. After a brief description of our experiment, our needs and experiences in time-keeping as well as suggestions for improvement in the broadcast of standard time signals are presented.