Ring in the mountains
It lies in the spurs of the Greater Caucasian ridge, in the two rivers of Bol'shoi Zelenchuk and Khusa. Huge, white. From a bird's eye view, it looks like a fragment of the mysterious "Nazca drawings" on the coast of Peru. And like those drawings left by an ancient civilization, it seems that this ring is a sign for aliens. Equal straight lines radiate out from the center of the ring. On them, from time to time, "ships" with square metal sails move. There is complete calm in the valley, but the sails are bent, a ray of the sun beats in them, as if not an earthly one, but the cosmic wind fills them.
And here I stand in the middle of the ring and see it from the inside. Around - a wall of metal plates almost closely pressed against each other, as high as a two-story house. Some of them are facing the sky. Suddenly, somewhere overhead, as if from the skies, a voice multiplied by a loudspeaker is heard: “Attention! On flat you can practice the following program. A minute passes, then another … In the ringing silence, the thrown back edge of the metal ring slowly aligns and at the same time its other edge tilts up to the heavens.
The barely noticeable movement of huge planes creates the impression that all this is happening not in reality, but in a fantastic dream. So one of the "ships" swam and swam to the center of the ring … it slides along the rails - these are the same radial straight lines emanating from the center of the ring. And the "solar sail" is the same metal plate as those that make up the ring.
All this is RATAN-600 - the world's largest ring radio telescope with a variable profile antenna, commissioned in 1974. RATAN is an abbreviation of the words Radio Telescope of the Academy of Sciences, number 600 is the diameter of its annular mirror in meters. The incredible device, the size of a stadium tribune, is located in a high-mountain valley, at an altitude of almost a kilometer above sea level. The mountains bordering the valley reliably protect RATAN from extraneous interference and atmospheric instabilities.
The radio telescope has become a "second window" for man to the sky, allowing one to see many phenomena and objects previously inaccessible to observation with optical instruments. With its help, it was possible to "probe" our Galaxy and establish its spiral shape. Quasars (quasi-stellar radio sources) and pulsars were unexpectedly discovered. Radio astronomers have discovered "relict radiation" - cosmic microwave radio emission from "nowhere" to "nowhere"; according to modern cosmological theories, we hear the echo of the Big Bang at the moment of the birth of the universe.
For radio astronomy there are no obstacles in the form of clouds or bright daylight - radio beams allow you to observe the "elusive" Mercury, which, due to its proximity to the Sun, is difficult to observe in ordinary telescopes - the planet rises above the horizon only in the hours of dawn and disappears from the sky immediately after sunset … The sensitivity of radio telescopes is amazing - the energy received by all radio telescopes in the world over the 80 years of radio astronomy is not enough to heat a drop of water by a hundredth of a degree.
Kingdom of Crooked Mirrors
To examine the ring in detail, you have to walk more than one hundred meters along the mown grass past the fragrant haystacks. In general, RATAN is a truly amazing object: the familiar earthly world and messages from the distant depths of the Cosmos intersect here. And while scientists go about their space affairs, among the giant parts of their instrument, the valley continues to live its normal life.
We come close to the plates that make up the ring. There are 895 of them in total, and each measuring 11.4 x 2 meters. There are wide gaps between the plates, and they themselves are not at all solid, but consist of smaller plates. Excuse me, - the reader will grin, - how is this carelessly assembled structure capable of capturing cosmic signals? Take a look at the radio telescope of the Arecibo Observatory (USA, 1963) - this is a real antenna!
In fact, the "curved" RATAN antenna has an enviable accuracy and is capable of bearing the coordinates of celestial objects with an accuracy of one arc second. In the process of creating large radio telescopes, it became clear that the dimensions of the mirrors cannot be increased infinitely - the accuracy of their real surfaces is gradually decreasing. Scientists and engineers ran into an insurmountable technological problem until they received a proposal to dismember the reflective mirror into separate elements and, using geodetic and radio methods, make perfectly smooth surfaces of any size from them.
RATAN-600 was created on the basis of N. L. Kaidanovsky. The Soviet astronomer proposed an original design, when instead of building a solid circular antenna, a ring of reflectors is used. The ring itself is the primary reflector; it is the first to collect the energy of cosmic radio signals. Taking into the "sight" a given part of the sky, the reflective elements of each sector are set in a parabola, forming a reflective and focusing band of the antenna, while not violating the ideal smoothness of the annular reflector. In the focus of such a strip, the irradiators are located, they collect and register radio waves collected by a giant antenna. The annular shape of the antenna provides an overview of the entire visible part of the sky, and the presence of several feeds allows you to simultaneously observe several space objects.
Perhaps we will not bore the reader with a list of meager scientific characteristics like the "limit for brightness temperature" or "limit for flux density." We only note that the true diameter of the "ring" is 576 meters, and the effective area of the antenna is 3500 square meters. meters. The radio telescope is capable of receiving instantaneous spectra of celestial objects in the range (0.6 ÷ 30 GHz). The rest of the information about RATAN can be easily found on the official website of the Russian Astrophysical Observatory
At RATAN, radio emissions from Jupiter's large satellites, Io and Europa, were first received, which are thousands of times weaker than the radiation from the giant planet. To distinguish them is all the same that at the other end of the street you can hear the breathing of the KAMAZ driver through the roar of the engine.
For almost 40 years, the radio telescope has been continuously observing the Sun, studying the state of our star, determining the nature of its excitations, and even learned how to diagnose "solar disturbances." Systematic studies of the Milky Way and extragalactic objects of the distant space are under way.
On March 17, 1980, the RATAN research team began an experiment codenamed "Cold" in order to look as deeply as possible into the Universe. The equipment was tuned to receive extremely weak signals, the sensitivity of the radio telescope was provided by ultra-low temperatures - the receivers were cooled by boiling helium vapor with a temperature of minus 260 ° C.
For 100 days, RATAN continuously looked at one point in the sky, as a result, due to the rotation of the Earth, not a point, but a narrow strip appeared in its field of view. Thousands of new objects were registered, distant from us for billions of light years, including the instantaneous spectrum of the quasar OQ172 - the most distant object in the Universe at that time. The density of the location of distant objects in space was heterogeneous - the further RATAN looked, the more the number of radio sources decreased. We can assume that somewhere there are none at all - there must be an opaque impassable wall - the "edge" of the Universe. And who knows if physicists are joking when they draw a border fence near the OQ-172 quasar?
The unique astronomical instrument RATAN-600, "listed in the Guinness Book of Records", is now in the department of the Russian Astrophysical Observatory and continues to explore the Universe. 20% of RATAN's working time is allocated for international researchers, the rest of the time the radio telescope works at the request of Russian astronomers. There are many applications - the average competition is 1: 3. The grandiose Soviet project was appreciated by scientists from all over the world.
