The GRAPES-3 experiment observes extensive air showers using a high-density array of scintillators and a large area tracking muon detector. The array consists of 300 scintillation detectors (each 1m^2 in area) and 16 modules of muon detectors having a total area of 560m^2. We have developed a new method of detector time offset correction to improve the angular resolution of the array by using shower data. We have been able to determine the angular resolution of the array using the shadow of Sun and Moon by using this method. The showers due to charged cosmic rays are identified by measuring their muon content using large area muon detector. Here we report on the status of the search for gamma rays from the `standard candle' CRAB nebula using the GRAPES-3 data.

GRAPES-3

Proceedings of the 30th International Cosmic Ray Conference; Rogelio Caballero, Juan Carlos D'Olivo, Gustavo Medina-Tanco, Lukas Nellen, Federico A. Sánchez, José F. Valdés-Galicia (eds.); Universidad Nacional Autónoma de México, Mexico City, Mexico, 2008; Vol. 2 (OG part 1), pages 819-822