The 1.2m Cassegrain telescope of the Astronomical Station Kryoneri, made by Grubb Parsons Co., was installed in 1975.
Its optical system consists of a paraboloidal primary mirror of 1.2m diameter and f/3 focal ratio, and a hyperboloidal secondary mirror (31 cm). Both mirrors are made of Zerodur. Its mounting is based on modified torque-tube equatorial system.
During its first 40 years of operation the telescope final focal ratio was f/13, with a field of view about 40’ and an image scale of 12.5"/mm. The main scientific instrument of the 1.2m Telescope has been the 2.5'x2.5' CCD camera Apogee Ap47p with UBVRI filters.
In 2016, the telescope underwent an extensive upgrade, which included replacement of the servo motors and associated hardware, and installation of a new computerised telescope control system. Furthermore, the optics of the telescope were modified to operate with instruments in the prime focus, bringing the telescope back to its original f/3 focal ratio, with a seeing-limited field of view of 1.4 degrees. The telescope primary mirror was also aluminised in October 2015, further increasing its sensitivity.