A variable star survey of the open cluster M 37

A CCD photometric study of the dense galactic open cluster M 37 is presente d and discussed. The majority of the analysed data are time-series measurem ents obtained through an R-C filter. The observations were carried out on s even nights between December 1999 and February 2000, and have led to the di scovery of 7 new variable stars in the field. Three of them have been unamb iguously identified as W UMa-type eclipsing binaries, while two more are mo noperiodic pulsating stars, most probably high-amplitude delta Scuti-type v ariables. The remaining two stars seem to be long-period eclipsing binaries without firm period determination. Johnson B and V frames have been used t o construct a new colour-magnitude (CM) diagram of the cluster, and to find the locations of the new variable stars. The pulsating variables are most likely background objects. The CM diagram is fitted with recent isochrones yielding the main parameters of the cluster.