Long-term correction of GRAPES-3 muon telescope efficiency

The GRAPES-3 experiment in Ooty, India has been operating a large area (560m$^2$) tracking muon telescope since 2000. It consists of 16 identical modules and each one is designed to measure the flux of muons in 13 $\times$ 13 directions covering 2.3 sr field of view. The high statistics data has enabled to probe transient space weather events on time scale of minutes. Due to independent nature of operation of the modules, despite intermittent failure of individual modules, a continuity in rate could still be achieved. By correcting for transient instrumental problems and gradual efficiency variations, an uninterrupted muon record is being assembled which may prove to be a valuable database for probing both transient and long-term solar phenomena. Details of the efficiency correction technique will be presented during the conference.