The Monitor Project: Stellar rotation at 13~Myr: I. A photometric monitoring survey of the young open cluster h~Per

We aim at constraining the angular momentum evolution of low mass stars by measuring their rotation rates when they begin to evolve freely towards the ZAMS, i.e. after the disk accretion phase has stopped. We conducted a multi-site photometric monitoring of the young open cluster h Persei that has an age of ~13 Myr. The observations were done in the I-band using 4 different telescopes and the variability study is sensitive to periods from less than 0.2 day to 20 days. Rotation periods are derived for 586 candidate cluster members over the mass range 0.4