Maximum Depth of Development of EASes with Energies above 1016 eV, Measured in Individual Events by Cherenkov Tracking Detectors

The Cherenkov radiation of extensive air showers (EASes) is studied using a system of optical tracking detectors based on a camera obscura as part of the Yakutsk EAS complex. These detectors allow photons to be counted from a certain height in the atmosphere and thus reconstruction of longitudinal development of a shower. Good coincidence is observed between EAS cascade curve parameter X max measured in this way and by modeling. Preliminary results on the cosmic ray mass composition are obtained for energies above 10 16 eV.