At present ZTA-2.6 telescope is the largest observational instrument of BAO operating since 1976. It was constructed at the LOMO (Leningrad Optical-Mechanical Association, Sent-Petersburg, Russia) and actually represents the twin of the G.A.Shain reflector mounted at the CrAO in 1960. Both these reflectors, as well as the 6m telescope of the Russian Special Astrophysical Observatory (SAO) have been designed by Bagrat Ioanissian – the LOMO General constructor.

The new main parabolic mirror of diameter 264cm made of sitall has been installed in 1984. Its relative focus distances are the followings: 3.85; 16 and 40.

The three-store building (tower) of the telescope has been designed by Sargis Gurzadyan the Observatory principal architect. The 60 ton dome is designed by Gurgen Minassian and built of duraluminum at the BOML (Byuarakan Optical Mechanical Laboratory).