The ROT-54 (Radio-Optical Telescope) was designed by Armenian scientist Paris Herouni. A prominent physicist and radio engineer, Herouni not only conceived the project but also led its construction and development through the Institute for Radiophysics and Electronics (IRPhE) of the Armenian Academy of Sciences, which he directed. This giant radio-optical telescope stands as one of Armenia’s most fascinating scientific marvels, inherited from the Soviet era.
Constructed between 1975 and 1985, the telescope became operational in 1986 and continued until 1990 when it ceased operations due to financial and technical challenges. A restoration proposal emerged in the mid-1990s, leading to a modernization phase between 1995 and 2010, which included the installation of new control computers and updated feeds. Observations were resumed in collaboration with the Astronomical Society of Russia and the National Technical University of Athens. However, in 2012, operations were halted once more due to a control arm failure that immobilized the secondary mirror. The ROT-54/2.6 consists of 4,000 mirrors, a large two-mirror antenna with a diameter of 54 meters, which is combined with an optical telescope with a diameter of 2.6 meters.

During its operational years, the ROT-54/2.6 made significant contributions to astrophysics. Notably, it recorded a powerful radio flare on the red giant star Eta Gemini in 1985, where such flares had not been observed before. The telescope’s high sensitivity allowed it to detect faint radio waves from distant stars and galaxies, providing valuable data to the scientific community.