The Kalyazin RT-64 is a massive 64-meter radio telescope situated near Kalyazin, Russia.

Constructed in the 1980s and operated by the Russian Academy of Sciences, it plays a key role in radio astronomy and deep-space communication.

As part of Russia's VLBI (Very Long Baseline Interferometry) network, it has contributed valuable data in the study of quasars, pulsars, and interstellar matter. Its size and sensitivity also make it a critical tool for global scientific partnerships and advanced astrophysical research.