On the Eurasian SubMillimeter Telescopes Project (ESMT)

The new challenges in the submillimeter astronomy call for the instruments combining high sensitivity and angular resolution, wide field of view, and multiwavelength (multicolor) spectral range. New single dish mm/submm telescopes in Eurasia are in high demand as well as their inclusion in the Event Horizon Telescope (EHT) VLBI network. The astroclimate studies aimed at the selection of the appropriate Eurasian site for a new mm/submm telescope began in 2012. The ESMT concept suggests the construction of three new mm/submm radio telescopes of 15-21 m class to be built in Suffa (Aktashtau), Uzbekistan, in Russia, and in Tibet, China to cover frequency bands up to 230 GHz (Russia), up to 350 GHz (Uzbekistan) and up to 1.5 THz (China). In the ESMT concept European ALMA antennas are taken as a starting point, increased their diameter to 21m, optimized an optical layout and the truss frame, supplemented an active surface and tertiary optics, including adaptive optics. Variants of the ESMT optical layout and tertiary optics are presented, which make it possible to maintain a compact dilution cryostat with KID-array camera in a vertical position during operation of the telescope to ensure its operability. The characteristics of the image quality of ESMT with a large-format KID-array camera in a field of view up to 10'×10' are estimated. The possibilities of applying active optics with the use of fast holography, precise laser trackers and radars and adaptive optics with a tilted tertiary mirror are considered.