The largest Chinese telescope. FAST telescope: first discoveries

A little more than a year ago, the world's largest radio telescope, FAST, a spherical radio telescope with a five-hundred-meter aperture, began operating in China. It was built with the aim of studying the origins and evolution of our universe. In addition, the telescope is expected to be able to study the formation and movement of galaxies, gravitational waves and dark matter, as well as molecules of interstellar space.

First discovery

Despite huge amount Conflicting information, including that thousands of people lost their land due to the construction of the telescope and that China did not have enough specialists to successfully launch it, FAST worked for a full year. Just recently, lab leaders published his first findings. They became pulsars - neutron stars, which rotate around their (slightly tilted) axis at enormous speed.

The importance of the telescope for science

According to the Chinese newspaper China Daily, the telescope was able to detect several dozen previously unknown pulsars. The existence and location of some of them was confirmed by a radio observatory in Australia.

According to the director of the FAST radio telescope, such results are a clear demonstration of the successful work of the observatory and specialists. Findings like these suggest that FAST will be extremely useful to the global scientific community, as it is powerful enough to sense signals from pulsars far beyond our galaxy.

In addition, the sensitivity of the radio telescope ensures that it will prove to be an important tool in studying the evolution of the universe and its mysterious composition ( dark matter and dark energy).

The telescope's sensitivity to radio waves emitted by pulsars also demonstrates the likelihood that FAST will be useful in further studies of gravitational waves.

Anticipation of future discoveries

It is expected that the Chinese FAST radio telescope will be able to double the number of known pulsars in the galaxy Milky Way. Today, we know of 2,700 pulsars within our galaxy, the first of which was discovered in 1967.

In addition to searching for radio waves emitted by pulsars as they rotate, the telescope is searching for signals from alien life forms. Experts do not place great hopes on discovering an extraterrestrial civilization; instead, they strive to find as much as possible more possibilities and areas in which FAST could be useful to modern astrophysics.

For example, very soon the radio telescope will begin searching for and studying complex interstellar molecules, as well as neutral hydrogen located in the vastness of the universe.

In my distant childhood, I came across a textbook on astronomy from those even more distant years, which I did not find when this astronomy was a subject at school. I read it thoroughly and dreamed of a telescope so that I could look into the night sky with at least one eye, but it didn’t work out. I grew up in a village where there was neither knowledge nor a mentor for this. And so this passion went away. But with age I discovered that the desire remained. I scoured the Internet, and it turns out there are a ton of people who are passionate about telescope construction and assembling telescopes, and what kind of telescopes, and from scratch. I gathered information and theory from specialized forums and decided to build a small telescope for a beginner.

If you had asked me earlier what a telescope is, I would have said - a tube, on one side you look, the other you point at the object of observation, in a word, a spyglass, but bigger size. But it turns out that for telescope construction they mainly use a different design, which is also called a Newtonian telescope. Despite its many advantages, it does not have many disadvantages compared to other telescope designs. The principle of its operation is clear from the figure - light distant planets falls on a mirror, which ideally has a parabolic shape, then the light is focused and carried outside the pipe using a second mirror, installed at 45 degrees relative to the axis, diagonally, which is called diagonal. Then the light enters the eyepiece and into the eye of the observer.


The telescope is accurate optical instrument Therefore, care must be taken during manufacturing. Before this, it is necessary to make calculations of the structure and installation locations of the elements. There are online calculators calculating telescopes and it would be a sin not to use this, but knowing the basics of optics also doesn’t hurt. I liked the calculator.

To make a telescope, in principle, nothing supernatural is needed, I think that anyone economic person in the utility room there is a small lathe, at least for wood, and even for metal. And if there is also a milling machine, I envy you with white envy. And it’s not at all uncommon now to have home CNC laser machines for cutting plywood and a 3D printing machine. Unfortunately, in my household I have nothing of all of the above, except for a hammer, drill, hacksaw, jigsaw, vice and small hand tools, plus a bunch of cans, trays with a scattering of tubes, bolts, nuts, washers and other garage scrap metal, which seems and I need to throw it away, but it’s a shame.

When choosing the size of the mirror (diameter 114mm), it seems to me that I chose golden mean, on the one hand, such a chassis size is no longer quite small, on the other hand, the cost is not so huge that in the event of a fatal failure you would suffer financially. Especially main task I had to touch it, figure it out and learn from mistakes. Although, as they say on all forums, the most good telescope it is the one in which one is observed.

And so, for my first, I hope not the last, telescope, I chose a spherical main mirror with a diameter of 114 mm and an aluminum coating, a focus of 900 mm and a diagonal mirror shaped like an oval with a small diagonal of one inch. With these mirror sizes and focal lengths, the differences between the shapes of a sphere and a parabola are negligible, so an inexpensive spherical mirror can be used.

According to Navashin’s book, Telescope of an Amateur Astronomer (1979), the internal diameter of the pipe for such a mirror must be at least 130 mm. Of course, more is better. You can make the pipe yourself from paper and epoxy, or from tin, but it would be a sin not to use ready-made cheap material - this time a meter-long PVH sewer pipe DN160, bought for 4.46 euros in a hardware store. The wall thickness of 4mm seemed sufficient to me in terms of strength. Easy to saw and process. Although there is one with a 6mm thick wall, it seemed a bit heavy to me. In order to saw it, I had to brutally sit on it; no residual deformations were visible to the eye. Of course, aesthetes will say fi, how can you look into the stars through a pipe for an Aries. But for real hands-on priests this is not an obstacle.

Here she is, beauty

Where to start? I started, in my opinion, with the most difficult one - the diagonal mirror mounting assembly. As I already wrote, the manufacture of a telescope requires precision, but that does not negate the possibility of adjusting the position of the same diagonal mirror. Without fine adjustment - nothing. There are several mounting schemes for a diagonal mirror: on one stand, on three stretchers, on four, and others. Each has its own pros and cons. Since the dimensions and weight of my diagonal mirror, and therefore its mounting, are, frankly speaking, small, I chose a three-beam mounting system. As stretch marks I used a found stainless steel adjustment sheet 0.2mm thick. As fittings I used copper couplings for a 22mm pipe with an outer diameter of 24mm, slightly smaller than the size of my diagonal, as well as an M5 bolt and M3 bolts. The central M5 bolt has a conical head, which, inserted into the M8 washer, acts as a ball joint, and allows you to tilt the diagonal mirror with the M3 adjusting bolts when adjusting. First I soldered the washer, then roughly cut it at an angle and adjusted it to 45 degrees on a sheet of coarse sandpaper. Both parts (one completely filled, the second 5mm through the hole) took less than 14 ml of five-minute two-component epoxy adhesive Moment. Since the dimensions of the unit are small, it is very difficult to place everything and for it all to work properly, the adjustment arm is not enough. But it turned out very, very well, the diagonal mirror is adjusted quite smoothly. I dipped the bolts and nuts into hot wax to prevent the resin from sticking when pouring. Only after the production of this unit did I order the mirrors. The diagonal mirror itself was glued to double-sided foam tape.


Below the spoiler are some photos of this process.

Diagonal Mirror Assembly

In the photo the mount already has a mirror, but without the rear disc.


Photo of the manufacturing process itself.

Mounting the main mirror

After assembly and primitive setup, the first tests were completed.


A problem immediately appeared. I ignored advice smart people Do not drill holes for mounting the main mirror without testing. It’s good that I sawed the pipe with a reserve. The focal length of the mirror turned out to be not 900mm, but about 930mm. I had to drill new holes (the old ones were sealed with electrical tape) and move the main mirror further. I just couldn’t get anything into focus; I had to lift the eyepiece itself from the focuser. The disadvantage of this solution is that the fastening and adjusting bolts at the end are not hidden in the pipe. but they stick out. In principle, it is not a tragedy.

I filmed it with my cell phone. At that time there was only one 6mm eyepiece, the degree of magnification was the ratio of the focal lengths of the mirror and the eyepiece. IN in this case it turns out 930/6=155 times.
Test number 1. 1 km to the object.




Number two. 3km.



The main result has been achieved - the telescope is working. It is clear that to observe the planets and the Moon, better alignment is needed. A collimator was ordered for it, as well as another 20mm eyepiece, and a filter for the Moon on a full moon. After this, all the elements were removed from the pipe and put back more carefully, more firmly and more accurately.

And finally, the purpose of all this is observation. Unfortunately starry nights in November there was practically none. Of the objects that I managed to observe, only two were the Moon and Jupiter. The moon does not look like a disk, but rather a majestically floating landscape. With a 6mm eyepiece, only part of it fits. And Jupiter with its satellites is simply a fairy tale, taking into account the distance that separates us. It looks like a striped ball with satellite stars on the line. It is impossible to distinguish the colors of these lines; here you need a telescope with another mirror. But it’s still fascinating. To photograph objects you need both additional equipment, and another type of telescope - high-aperture with low focal length. Therefore, here are only photos from the Internet that accurately illustrate what is visible with such a telescope.

Unfortunately, you will have to wait until spring to observe Saturn, but for now Mars and Venus are in the near future.

It is clear that mirrors are not the only cost of construction. Here is a list of what was purchased besides this.

Telescope FAST

The 500-meter FAST radio telescope, the world's largest filled aperture telescope, has been put into operation in China. In terms of its diameter, it is second only to RATAN-600, located in Karachay-Cherkessia, which, however, does not have a filled aperture. The closest analogue of FAST is the 300-meter radio telescope at the Arecibo Observatory. Xinhua agency reports this.

The dimensions of the telescope determine its performance characteristics - sensitivity, resolution, and so on. The larger the radio telescope, the smaller or more distant objects it can detect. In terms of resolution, the absolute record holder is RadioAstron. This is a monitoring system space objects using ultra-long baseline interferometry, consisting of the Spektr-R space radio telescope and various ground-based radio telescopes. Together they form an instrument equivalent to a radio telescope with a diameter of about one hundred thousand kilometers.

However, such systems have low sensitivity due to their small effective area. General sensitivity is defined as the geometric mean of the sensitivity of the 10-meter Spektr-R and the ground-based radio telescope operating in tandem with it. Therefore, such observations require high-sensitivity ground-based instruments. In addition, new radio telescopes expand the tools available to astronomers around the world.

The new radio telescope is located in Guizhou province and has an area of ​​about 30 football fields. Despite the 500-meter diameter, observations will use reflector fragments with a diameter of about 300 meters - this is the effective diameter of the telescope. By this indicator, FAST is only slightly better than the Arecibo Observatory (221 meters). The 500-meter reflector will allow the telescope to have a much larger field of view.

After commissioning, the first test observations were already carried out at the telescope. According to Qian Lei, a researcher from the National Astronomical Laboratory (China), the telescope successfully detected a signal from one of the pulsars located in 1351 light year from the Earth.

FAST's tasks will include tracking pulsars, studying interstellar gas, searching for complex molecules, and analyzing objects from the reionization era. Scientists expect the radio telescope to double the number of pulsars known to science. This can help in the search for gravitational wave signals in "glitches" of pulsar radiation (such observations, for example, by the NANOGrav consortium). Representatives of the RadioAstron project previously stated that FAST will be able to work in tandem with Spektr-R. The radio telescope will be tuned for the first two to three years after commissioning, after which it will become available to the international community.

Interestingly, to build the telescope, the Chinese authorities had to resettle about 9,000 local residents beyond the five-kilometer zone around the telescope. Construction took place in July 2016. Next to the telescope there is an observation deck, to which access will be organized for tourist groups - up to two thousand people a day. The cost of a ticket for it will be about 3.5 thousand rubles in terms of Russian money.

Vladimir Korolev

— The whole world was talking about the largest radio telescope, which was launched yesterday in China. How do you assess the importance of this event?

“It would probably be more correct to call this the official completion of the telescope’s construction.” You can call this a discovery, but you need to understand that for all instruments of this class in the world, without exception, it takes years to put them into full operation.

Years since the completion of their construction is announced.

This is due to the fact that such telescopes are technologically extremely complex. And to achieve the parameters that were included in the project, a lot of work is required.

— What is special about the telescope design?

— The FAST telescope is a 500-meter mirror placed inside a natural depression, which has been slightly straightened. His geometric shape- sphere. Aim at different objects in heaven he can with great difficulty simply because different objects in different times in the sky are in different places. The telescope is similar to the 300-meter Arecibo radio telescope, which is also located in a natural depression. Sometimes, by the way, they say that Arecibo was built in the crater of a volcano, in fact - in sinkhole. Arecibo is aimed at objects in a fairly limited range of angles by moving the secondary mirror on three cables.

Our Chinese colleagues have made fundamental changes to this scheme, thanks to which FAST will have significantly greater capabilities for pointing at and tracking a celestial object.

In fact, FAST will see a much larger area of ​​the sky, roughly about 2/3 of the entire sky.

How? FAST will actually have an active surface. The 4.5 thousand panels from which it is made cannot yet move. Therefore, the first observations will be made while the telescope is a sphere, at or near the zenith. But within a year or two, Chinese colleagues should learn to make this area active. That is, each panel in real time will be able to adapt to a paraboloid of rotation directed to the point in the sky from which we want to catch radiation. As a result, it won't lose its effective area like Arecibo does, and it will be able to target a wider range of sources and track them for longer. This is a major leap forward relative to Arecibo, not only due to an increase in area, but also due to the introduction of an active surface.

— What will this telescope be the best at?

- He will be the most sensitive. Bye. Because if you sum up the collecting surface, it has the largest one. It will only be most sensitive at the wavelengths at which it operates. Obviously, at short wavelengths it will no longer be able to compete with telescopes such as the Effelsberg antenna, Green Bank Telescope, ALMA and others.

— What are the declared and real goals radio telescope?

— Firstly, these are radio pulsars. Because pulsars have an incident spectrum: the shorter the wavelength, the weaker the signal. Therefore, any telescope operating on long waves, very suitable for pulsars, FAST for studying pulsars would be awesome.

Pulsars are interesting in themselves, let's not forget that these are the most accurate clocks in the world, and that today this is the coolest way to test predictions arising from general theory relativity.

In addition, based on pulsars, it is proposed to build a circuit that catches gravitational waves. And this scheme will not replace the ground-based gravitational interferometer LIGO simply because they are focused on studying gravitational waves of different frequencies. The many pulsars in the sky can actually be used as reference points, and we can explore how the Earth shakes relative to them. After all, the Earth is the very brick that trembles when space-time changes.

The second task will be the study of dark matter.

One of the reasons we know it exists is because of the rotation curves of neutral hydrogen in the disks of galaxies. If we want to get statistics, rich material on a large number galaxies, obviously we need a sensitive telescope, and FAST will do that.

Since this is the most sensitive telescope in the world at a wavelength of 18 cm, then it will be able to do this for more galaxies located further away.

Undoubtedly important task will be the study of so-called ultrafast radio bursts (FRBs). Many of them are quite weak, some were just opened with the help of Arecibo. The problem with such telescopes is that the area of ​​the sky that they can observe at any given time is small. But this problem can be solved. It is necessary to build a multi-beam system with several radiation receivers, which is somewhat reminiscent of CCD matrices in optics. If the Chinese do this, they can get serious about FRBs. And this is cool, since fast radio bursts are detected strictly at those waves on which FAST will operate.

It is still not clear what they are, there is a whole zoo of fast radio bursts, and this telescope will be able to study them much better and collect their statistics.

— The main thing is not to open microwave ovens that are not turned off. FRBs in Australia were erroneously recorded when employees near a radio telescope opened the oven door without turning it off. They didn't wait for the furnace to finish working.

— The whole world is shouting that the telescope will look for life in the Universe. Even The New York Times came out with the headline "China seeks scientific glory and aliens." Is this some kind of populism aimed at attracting attention?

— Obviously, this is being written because it is incomparably easier to explain than the scientific tasks facing the telescope. It’s just that journalists don’t bother to spend time and effort explaining it.

And they can be understood: they need to be read, and most people in the world will not spend more than a minute reading this news.

And with so many characters you won’t be able to write about anything other than “little green men”. At the same time, there is nothing shameful in searching for extraterrestrial intelligence; this is a normal task, one of many that the telescope will solve. I was in China when the FAST builders gave a report on the scientific problems that would be solved. The discussion was professional, there was no populism. This is a very serious project, and the main thing in it is not even science, but technologies that no one else has come up with before.

As for access to the telescope, obviously it will not be closed to the whole world. Around him, a couple of years ago, international working groups were organized to study prospects for various scientific tasks. It will be accessible to scientists around the world, just like any other major radio telescope today.

— In light of this, will the telescope be used in such international projects, like “Very Long Baseline Radio Interferometry” (VLBI), your “Radioastron” and others?

- Without a doubt, it will be. We really hope that it will be used in the Radioastron program. I hope that our Chinese colleagues will introduce interferometric mode, that is, the opportunity to participate in VLBI programs, before Radioastron ceases its activities. Today, the situation at Radioastron is very good; Roscosmos has extended funding for observations until the end of 2018.

If FAST introduces interferometry before this time, we will definitely work together.

Today, in this mod, we work with all Chinese radio telescopes. This is a 25-meter mirror in Urumqi, a 25-meter mirror near Shanghai and a 65-meter mirror also near Shanghai.

— What place does China occupy today in world radio astronomy and what will it occupy with the introduction of the new telescope?

— Our Chinese radio astronomer colleagues still have room to grow. This is clearly visible, and our Chinese colleagues themselves admit that they still have a shortage of highly qualified personnel in radio astronomy. And in this sense, FAST is one of the ways in which they can fill this shortage of personnel by conducting active training on two, and soon on three, new radio telescopes.

The first is a 65-meter full-revolving mirror with an active surface near Shanghai, which was commissioned a year ago, the second is FAST, and there will be a third

— China begins construction of a record-breaking 110-meter fully rotating telescope in Urumqi.

They will have three high-end telescopes on which they can forge their frames. Those things that their industry can produce on their own, they do themselves. And what they cannot do, they buy. For example, they buy receivers for radio telescopes and the electronics behind them in the USA from National Radio astronomical observatory.

As for the future of global radio astronomy, it is moving towards a 1 square meter antenna array. km SKA (Square Kilometer Array). The first phase of SKA will be built in Australia and South Africa and will be comparable to FAST. But the second phase of SKA, which will be based on large quantities small telescopes will be incomparably more sensitive than FAST.

— With the introduction of these capacities, will radio astronomy receive a quantitative or qualitative leap?

- Undoubtedly, high quality. Because if you are interested not only in new technologies, but also in the opportunity to make sure that a new telescope will provide qualitatively new scientific results, there is an unwritten rule,

that to do this you need to build a telescope that is an order of magnitude better in one of the key parameters.

One of these parameters is sensitivity, or collecting surface. Radioastron took the path of improving angular resolution, increasing it ten times or more, and we got results that no one could have predicted before us. It’s the same with FAST - the huge collecting area will translate into quality and give interesting results.

In the Chinese province of Guizhou this week, construction was completed on the world's largest filled aperture radio telescope, called FAST (Five hundred meter Aperture Spherical Telescope), whose bowl area exceeds 30 football fields.

Radio telescope FAST (Five hundred meter Aperture Spherical Telescope)

FAST received the title of the largest ground-based radio telescope in the world.

The huge disk was assembled from individual 4450 triangular panels (reflectors). It is noted that the diameter of the FAST reflector is 500 meters, which is 200 meters larger than that of its closest competitor, the famous 300-meter Arecibo Observatory in Puerto Rico.

One of the scientists involved in the FAST project once said that his parabolic antenna could fit so many bottles of wine that each of the 7 billion people on Earth would have enough of five bottles.

With the help of such a device it will be possible to observe objects at a distance of up to 11 billion light years. The new radio telescope will make it possible to observe and discover various astronomical objects and phenomena that occur too far from Earth and whose radio signals are too weak to be captured by small telescopes. Also, the tasks of the FAST radio telescope will include hunting for aliens.

"The size of this telescope is key to its scientific purpose. The larger the telescope, the more radio waves it will be able to pick up and the more dim objects can then be seen,” says Tim O'Brien of the University of Manchester, deputy director of the UK's Jodrell Bank Observatory.

Construction of the FAST radio telescope began in the southwestern province of Guizhou back in 2011, and the project cost about $180,000,000. To create the telescope, it was necessary to resettle more than 9 thousand people living in the mountainous counties of Pingtang and Luodian within a radius of 5 km from the construction site. And the government paid each of them compensation in the amount of $1,800.

The telescope is located in a natural crater, which is ideal for housing a huge concave bowl. The telescope was designed so that individual panels could be rearranged to track radio waves from specific objects. This gives the device a much greater range and sensitivity compared to other telescopes.

According to O'Brien, FAST will allow for more thorough studies of pulsars - astronomical objects that emit powerful, strictly periodic pulses. electromagnetic radiation mainly in the radio range.

“We will be able to find more pulsars outside our Galaxy. The telescope will also allow us to study hydrogen in very distant galaxies, search for natural radio waves emitted by exoplanets orbiting other stars, and help search for radio signals extraterrestrial civilizations"O'Brien notes.

Zheng Xiaonian, deputy head of the State Astronomical Observatory of the Chinese Academy of Sciences, says observations will begin in September 2016 after the telescope has been thoroughly tested by specialists. FAST, he said, will be a "global leader" for ten to 20 years, and will help humanity better understand the emergence of the universe.

The world's largest radio telescope "FAST"

A radio telescope is an astronomical instrument that is capable of receiving the own radio emissions of celestial objects and studying their characteristics.

It consists of an antenna device and a sensitive receiving device (radiometer), which amplifies the received radio emission and converts it into a form convenient for recording and processing.

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