The Orgov Radio-Optical Telescope, also known as ROT54 or the Herouni Mirror Radio Telescope, is a radio telescope in Orgov, Armenia. It was built between 1975-1985 and was active between 1986-1990 before its use was halted. Model is scaled 1:1.
3600 shields made of high-strength alloys based on aluminum with additions of copper, magnesium and manganese, in turn attached to iron pipes, were “walled up” in the pit. Of particular technical difficulty was the polishing of the shields (with an average size of one by one meter) that covered the telescope mirror, because the reception of radio waves in the millimeter and sub-millimeter ranges depends on the quality of the surface of the shields. Therefore, each panel of the mirror was hand-molded and precision-finished to within 70 microns. Wikipedia