РАТАН-600: Әлемдегі ең ірі радиотелескоп

Radio telescope at the Special Astrophysical Observatory in southern Russia

The RATAN 600 (РАТАН 600 – радиоастрономический телескоп Академии наук – 600, an acronym for the "Academy of Sciences Radio Telescope – 600") is a radio telescope in Zelenchukskaya, Karachay–Cherkess Republic, Russia. It comprises a 576 m diameter circle of rectangular radio reflectors and a set of secondary reflectors and receivers, based at an altitude of 970 m. Each of the 895 2×7.4 m reflectors can be angled to reflect incoming radio waves towards a central conical secondary mirror, or to one of five parabolic cylinders. Each secondary reflector is combined with an instrumentation cabin containing various receivers and instruments. The overall effect is that of a partially steerable antenna with a maximum resolving power of a nearly 600 m diameter dish, when using the central conical receiver, making it the world's largest diameter individual radio telescope.

It has a resolving power in the horizontal plane of 1 arcminute at a wavelength of 8 cm (3.75 GHz). The effective collecting area of the entire ring is which is 0.33% of that expected of a completely filled reflector of this size.

The RATAN 600 is primarily operated as a transit telescope, in which the rotation of the Earth is used to sweep the telescope focus across the subject of observation. Radio frequency observations can be made in the frequency band 610 MHz to 30 GHz, though primarily in the centimetric waveband, with an angular resolution of up to 2 arcseconds. Observation of the Sun at radio wavelengths, in particular of the solar corona, has been a long standing focus of the RATAN 600's scientific programme. It has also contributed to radio observation for the SETI project. The RATAN 600 has not suffered from the persistent technical problems of the neighbouring BTA 6, and has generally been in high demand since it began operation in mid 1974.

On 15 May 2015, at 18:01:15.65 sidereal time, RATAN 600 detected a strong (0.75 Jansky) signal from the direction of HD164595. More specifically, the signal intensity rose and fell as the telescope panned past in a way that closely matched what would be expected for a distant source. Since the short wavelength (2.7 cm, or 11 GHz, in the X band) is unusual for a natural source of that power, after the researchers announced the signal in late August 2016 (in the form of a request for follow up observations) there was a flurry of excitement that it might be a SETI candidate. Of course, the same artificial appearance also makes a terrestrial source likely. Because the signal is in a frequency band allocated to military use, it might have originated from a secret reconnaissance satellite. After further analysis, and a failure of other observatories to corroborate the signal, the Special Astrophysical Observatory concluded that it was of probably terrestrial origin. Later research suggests that it might have been a faulty satellite in a slow spin, as the frequency matches one used for inter satellite beacons, but was more likely to be the downlink from an intact but classified satellite.