The term telescope literally means “looking far away.” Modern optical devices allow astronomers to study our solar system, as well as discover new planets located beyond its borders. The top ten below includes the most powerful telescopes in the world.
BTA
BTA opens the ranking of the most powerful telescopes, which has one of the largest monolithic mirrors in the whole world. This giant, built in the 70s of the last century, still holds the advantage in terms of the largest astronomical dome. The mirror with a diameter of over 6 meters is made in the form of a paraboloid of rotation. Its mass is forty-two tons, if you do not take into account the weight of the frame. The total mass of this giant is 850 tons. The chief designer of the BTA is B.K. Ionnisani. The reflective mirror coating was made of unprotected aluminum. The working layer requires replacement every ten years.
Giant Magellan Telescope is one of the ten largest and most powerful in the world. Full completion of its construction is planned for 2020. To collect light, a system will be used that includes seven primary mirrors, each of which will have a diameter of 8.4 m. The total aperture of the device will correspond to a telescope with a mirror more than 24 m in diameter. Presumably, the MHT will be several times more powerful than all modern telescopes. It is planned that MHT will become the most powerful and will help discover many new exoplanets.
Gemini South and Gemini North
Gemini South And Gemini North are a complex that includes two telescopes, eight meters high. They are designed to provide full, unobstructed coverage of the sky and are located on different peaks. These are some of the most powerful and advanced infrared optical telescopes available today. The devices provide the clearest possible images, which is achieved using spectroscopy and adaptive optics. Telescopes are often controlled remotely. The devices are actively involved in the search for exoplanets.
Subaru
Subaru- one of the most powerful telescopes in the world, created by Japanese scientists. It is located at the top of the Mauna Kea volcano. It has one of the largest monolithic mirrors in the world with a diameter of more than eight meters. Subaru is capable of detecting planets outside our solar system, and can also determine their size by studying planetary light and detect the gases that dominate the atmosphere of exoplanets.
Hobby-Eberly Telescope
Hobby-Eberly Telescope is one of the ten most powerful telescopes today with a main mirror diameter exceeding nine meters. During its creation, many innovations were used, which is one of the main advantages of this device. The main mirror includes 91 elements that function as a single unit. Hobby - Eberly is used both to study our solar system and to study extragalactic objects. With its help, several exoplanets were discovered.
SALT
SALT– the full name sounds like Southern African Large Telescope. The optical device has a large main mirror, the diameter of which is eleven meters and consists of an array of mirrors. It is located on a hill almost 1.8 km high near the province of Sutherland. Using this device, astronomy specialists conduct research into nearby galaxies and find new planets. This most powerful astronomical device allows for various types of analyzes of the radiation of astronomical objects.
LBT or Large Binocular Telescope translated into Russian means Large Binocular Telescope. It is one of the most technologically advanced devices that has the highest optical resolution in the world. It is located at an altitude of more than 3 kilometers on a mountain called Graham. The device includes a pair of huge parabolic mirrors with a diameter of 8.4 m. They are installed on a common mount, hence the name “binocular”. In terms of its power, the astronomical instrument is equivalent to a telescope with one mirror having a diameter of more than 11 meters. Thanks to its unusual structure, the device is capable of producing images of one object simultaneously through different filters. This is one of its main advantages, because thanks to this you can significantly reduce the time to obtain all the necessary information.
Keck I and Keck II
Keck I and Keck II located at the very top of Mauna Kea, whose height exceeds 4 kilometers above sea level. These astronomical instruments are capable of operating in interferometer mode, which is used in astronomy for high-resolution telescopes. They can replace a large aperture telescope with an array of devices with small apertures that are connected like an interferometer. Each of the mirrors consists of thirty-six small hexagonal ones. Their total diameter is ten meters. Telescopes were created according to the Ritchie-Chretien system. The twin devices are controlled from the Waimea headquarters offices. It was thanks to these astronomical units that most of the planets located outside the solar system were found.
GTC– this abbreviation translated into Russian means the Grand Canary Telescope. The device really has an impressive size. This optical reflecting telescope has the largest mirror in the world, the diameter of which exceeds ten meters. It is made from 36 hexagonal segments, which were obtained from Zerodur glass-crystalline materials. This astronomical device has active and adaptive optics. It is located at the very top of the extinct Muchachos volcano in the Canary Islands. A special feature of the device is the ability to see various objects at a very large distance, billions weaker than the naked human eye can distinguish.
VLT or Very Large Telescope, which translated into Russian means “very large telescope.” It is a complex of devices of this type. It includes four separate and the same number of optical telescopes. This is the largest optical device in the world in terms of total mirror area. It also has the highest resolution in the world. The astronomical device is located in Chile at an altitude of more than 2.6 km on a mountain called Cerro Paranal, located in the desert near the Pacific Ocean. Thanks to this powerful telescopic device, a couple of years ago scientists finally managed to get clear photographs of the planet Jupiter.
Today, telescopes are still one of the main tools of astronomers, both amateur and professional. The task of the optical instrument is to collect as many photons as possible at the light receiver.
In this article we will touch on optical telescopes and briefly answer the question: “why does the size of the telescope matter?” and consider a list of the largest telescopes in the world.
First of all, it should be noted the differences between a reflecting telescope and a telescope. A refractor is the very first type of telescope, which was created in 1609 by Galileo. The principle of its operation is to collect photons using a lens or lens system, then reduce the image and transmit it to the eyepiece, which the astronomer looks through during observation. One of the important characteristics of such a telescope is the aperture, the high value of which is achieved, among other things, by increasing the size of the lens. Along with the aperture, the focal length is also of great importance, the value of which depends on the length of the telescope itself. For these reasons, astronomers sought to enlarge their telescopes.
Today, the largest refracting telescopes are located in the following institutions:
- At the Yerkes Observatory (Wisconsin, USA) - with a diameter of 102 cm, created in 1897;
- At the Lick Observatory (California, USA) - with a diameter of 91 cm, created in 1888;
- At the Paris Observatory (Meudon, France) - with a diameter of 83 cm, created in 1888;
- At the Potsdam Institute (Potsdam, Germany) - with a diameter of 81 cm, created in 1899;
Modern refractors, although they have stepped significantly further than Galileo’s invention, still have such a disadvantage as chromatic aberration. Briefly speaking, since the angle of refraction of light depends on its wavelength, then, when passing through the lens, light of different lengths seems to be stratified (light dispersion), as a result of which the image looks fuzzy and blurry. Despite the fact that scientists are developing new technologies to improve clarity, such as ultra-low dispersion glass, refractors are still in many ways inferior to reflectors.
In 1668, Isaac Newton developed the first. The main feature of such an optical telescope is that the collecting element is not a lens, but a mirror. Due to the distortion of the mirror, a photon incident on it is reflected into another mirror, which, in turn, directs it into the eyepiece. Different designs of reflectors differ in the relative position of these mirrors, but one way or another, reflectors relieve the observer from the consequences of chromatic aberration, giving the output a clearer image. In addition, reflectors can be made of much larger sizes, since refractor lenses with a diameter of more than 1 m are deformed under their own weight. Also, the transparency of the refractor lens material significantly limits the range of wavelengths compared to the reflector device.
Speaking about reflecting telescopes, it should also be noted that as the diameter of the main mirror increases, its aperture also increases. For the reasons described above, astronomers are trying to get the largest optical reflecting telescopes.
List of largest telescopes
Let's consider seven telescope complexes with mirrors with a diameter of more than 8 meters. Here we tried to organize them according to such a parameter as aperture, but this is not a determining parameter for the quality of observation. Each of the listed telescopes has its own advantages and disadvantages, certain tasks and the characteristics required to perform them.
- The Grand Canary Telescope, opened in 2007, is the largest aperture optical telescope in the world. The mirror has a diameter of 10.4 meters, a collecting area of 73 m², and a focal length of 169.9 m. The telescope is located in the Roque de los Muchachos Observatory, which is located on the peak of the extinct Muchachos volcano, approximately 2400 meters above sea level, in one of the Canary Islands. islands called Palma. The local astroclimate is considered the second best for astronomical observations (after Hawaii).
The Grand Canary Telescope is the largest telescope in the world
- Two Keck telescopes have mirrors with a diameter of 10 meters each, a collecting area of 76 m² and a focal length of 17.5 m. They belong to the Mauna Kea Observatory, which is located at an altitude of 4145 meters, on the peak of Mauna Kea (Hawaii, USA). The Keck Observatory has the largest number of exoplanets discovered.
- The Hobby-Eberly Telescope is located at the McDonald Observatory (Texas, USA) at an altitude of 2070 meters. Its aperture is 9.2 m, although physically the main reflector mirror has dimensions of 11 x 9.8 m. The collecting area is 77.6 m², the focal length is 13.08 m. The peculiarity of this telescope lies in a number of innovations. One of them is movable instruments located at the focus, which move along a fixed main mirror.
- The Large South African Telescope, owned by the South African Astronomical Observatory, has the largest mirror - 11.1 x 9.8 meters. However, its effective aperture is slightly smaller - 9.2 meters. The collecting area is 79 m². The telescope is located at an altitude of 1783 meters in the semi-desert region of the Karoo, South Africa.
- The Large Binocular Telescope is one of the most technologically advanced telescopes. It has two mirrors (“binocular”), each of which has a diameter of 8.4 meters. The collecting area is 110 m² and the focal length is 9.6 m. The telescope is located at an altitude of 3221 meters and belongs to the Mount Graham International Observatory (Arizona, USA).
- The Subaru telescope, built back in 1999, has a diameter of 8.2 m, a collecting area of 53 m² and a focal length of 15 m. It belongs to the Mauna Kea Observatory (Hawaii, USA), the same as the Keck telescopes, but there are six meters lower - at an altitude of 4139 m.
- VLT (Very Large Telescope - from English “Very Large Telescope”) consists of four optical telescopes with diameters of 8.2 m and four auxiliary ones - 1.8 m each. The telescopes are located at an altitude of 2635 m in the Atacama Desert, Chile. They are under the control of the European Southern Observatory.
Very Large Telescope (VLT)
Direction of development
Since the construction, installation and operation of giant mirrors is a fairly energy-intensive and expensive undertaking, it makes sense to improve the quality of observation in other ways, in addition to increasing the size of the telescope itself. For this reason, scientists are also working towards developing the surveillance technologies themselves. One such technology is adaptive optics, which allows minimizing distortion of the resulting images as a result of various atmospheric phenomena.
Taking a closer look, the telescope focuses on a star bright enough to determine the current atmospheric conditions, resulting in the resulting images being processed to take into account the current astroclimate. If there are not enough bright stars in the sky, the telescope emits a laser beam into the sky, forming a spot on it. Using the parameters of this spot, scientists determine the current atmospheric weather.
Some optical telescopes also operate in the infrared range of the spectrum, which makes it possible to obtain more complete information about the objects under study.
Projects for future telescopes
Astronomers' tools are constantly being improved and the most ambitious projects of new telescopes are presented below.
- it is planned to be built in Chile, at an altitude of 2516 meters, by 2022. The collecting element consists of seven mirrors with a diameter of 8.4 m, while the effective aperture will reach 24.5 m. The collecting area is 368 m². The resolution of the Giant Magellan Telescope will be 10 times greater than that of the Hubble Telescope. The light-gathering capacity will be four times greater than that of any current optical telescope.
- The thirty-meter telescope will belong to the Mauna Kea Observatory (Hawaii, USA), which also includes the Keck and Subaru telescopes. They intend to build this telescope by 2022 at an altitude of 4050 meters. As the name suggests, the diameter of its main mirror will be 30 meters, the collecting area will be 655 m2, and the focal length will be 450 meters. The thirty-meter telescope will be able to collect nine times more light than any existing one, its clarity will be 10-12 times greater than that of Hubble.
- (E-ELT) is the largest telescope project to date. It will be located on Mount Armazones at an altitude of 3060 meters, Chile. The E-ELT mirror will have a diameter of 39 m, a collecting area of 978 m2 and a focal length of up to 840 meters. The telescope's collecting power will be 15 times greater than any existing telescope today, and its image quality will be 16 times better than Hubble's.
The telescopes listed above go beyond the visible spectrum and are also capable of capturing images in the infrared region. Comparing these ground-based telescopes with the Hubble orbiting telescope means that scientists have overcome the barrier of atmospheric interference while outperforming the powerful orbiting telescope. All three of these devices, together with the Large Binocular Telescope and the Grand Canary Telescope, will belong to a new generation of so-called Extremely Large Telescopes (ELT). 
March 23rd, 2018
The James Webb Telescope is an orbital infrared observatory that will replace the famous Hubble Space Telescope. The James Webb will have a composite mirror 6.5 meters in diameter and cost about $6.8 billion. For comparison, the diameter of the Hubble mirror is “only” 2.4 meters.
Work on it has been going on for about 20 years! The launch was initially scheduled for 2007, but was later postponed to 2014 and 2015. However, the first segment of the mirror was installed on the telescope only at the end of 2015, and the entire main composite mirror was assembled only in February 2016. Then they announced a launch in 2018, but according to the latest information, the telescope will be launched using an Ariane 5 rocket in the spring of 2019.
Let's see how this unique device was assembled:
The system itself is very complex; it is assembled in stages, checking the performance of many elements and the already assembled structure during each stage. Starting in mid-July, the telescope began to be tested for performance at ultra-low temperatures - from 20 to 40 degrees Kelvin. The operation of the telescope's 18 main mirror sections was tested over several weeks to ensure that they could operate as a single unit. The diameter of the telescope's composite mirror is 6.5 meters.
Later, after everything turned out to be fine, scientists tested the orientation system by emulating the light of a distant star. The telescope was able to detect this light; all optical systems were operating normally. The telescope was then able to locate the “star” by tracking its characteristics and dynamics. Scientists are convinced that the telescope will work quite correctly in space.
The James Webb Telescope should be placed in a halo orbit at the L2 Lagrange point of the Sun-Earth system. And it's cold in space. Shown here are tests conducted on March 30, 2012, to examine the ability to withstand the cold temperatures of the space. (Photo by Chris Gunn | NASA):
In 2017, the James Webb telescope was again conducted under extreme conditions. He was placed in a chamber in which the temperature reached only 20 degrees Celsius above absolute zero. In addition, there was no air in this chamber - scientists created a vacuum in order to place the telescope in outer space conditions.
“We are now confident that NASA and the agency's partners have built an excellent telescope and set of scientific instruments,” said Bill Ochs, James Webb Project Manager at Goddard Space Flight Center.
The James Webb will have a composite mirror 6.5 meters in diameter with a collecting surface area of 25 m². Is this a lot or a little? (Photo by Chris Gunn):
But that’s not all, the telescope still has to undergo many checks before it is considered fully ready for shipment. Recent tests have shown that the device can operate in a vacuum at ultra-low temperatures. These are the conditions that prevail at the L2 Lagrange point in the Earth-Sun system.
In early February, James Webb will be transported to Houston, where he will be placed on a Lockheed C-5 Galaxy aircraft. On board this giant, the telescope will fly to Los Angeles, where it will be finally assembled with a sun shield installed. Scientists will then check whether the entire system works with such a screen, and whether the device can withstand vibration and stress during flight.
Let's compare with Hubble. Hubble (left) and Webb (right) mirrors on the same scale:
4. Full-scale model of the James Webb Space Telescope in Austin, Texas, March 8, 2013. (Photo by Chris Gunn):
5. The telescope project is an international collaboration of 17 countries, led by NASA, with significant contributions from the European and Canadian Space Agencies. (Photo by Chris Gunn):
6. Initially, the launch was planned for 2007, but was later postponed to 2014 and 2015. However, the first segment of the mirror was installed on the telescope only at the end of 2015, and the main composite mirror was not fully assembled until February 2016. (Photo by Chris Gunn):
7. The sensitivity of a telescope and its resolution are directly related to the size of the mirror area that collects light from objects. Scientists and engineers have determined that the minimum diameter of the primary mirror must be 6.5 meters in order to measure light from the most distant galaxies.
Simply making a mirror similar to that of the Hubble telescope, but larger, was unacceptable, since its mass would be too large to launch the telescope into space. The team of scientists and engineers needed to find a solution so that the new mirror would have 1/10 the mass of the Hubble telescope mirror per unit area. (Photo by Chris Gunn):
8. Not only here everything becomes more expensive from the initial estimate. Thus, the cost of the James Webb telescope exceeded the original estimates by at least 4 times. It was planned that the telescope would cost $1.6 billion and be launched in 2011, but according to new estimates, the cost could be 6.8 billion, but there is already information about exceeding this limit to 10 billion (Photo by Chris Gunn):
9. This is a near-infrared spectrograph. It will analyze a range of sources, which will provide information about both the physical properties of the objects under study (for example, temperature and mass) and their chemical composition. (Photo by Chris Gunn):
The telescope will make it possible to detect relatively cold exoplanets with a surface temperature of up to 300 K (which is almost equal to the temperature of the Earth’s surface), located further than 12 AU. that is, from their stars, and distant from Earth at a distance of up to 15 light years. More than two dozen stars closest to the Sun will fall into the detailed observation zone. Thanks to James Webb, a real breakthrough in exoplanetology is expected - the capabilities of the telescope will be sufficient not only to detect the exoplanets themselves, but even the satellites and spectral lines of these planets.
11. Engineers test in the chamber. telescope lift system, September 9, 2014. (Photo by Chris Gunn):
12. Research of mirrors, September 29, 2014. The hexagonal shape of the segments was not chosen by chance. It has a high fill factor and has sixth order symmetry. A high fill factor means that the segments fit together without gaps. Thanks to symmetry, the 18 mirror segments can be divided into three groups, in each of which the segment settings are identical. Finally, it is desirable that the mirror has a shape close to circular - to focus the light on the detectors as compactly as possible. An oval mirror, for example, would produce an elongated image, while a square one would send a lot of light from the central area. (Photo by Chris Gunn):
13. Cleaning the mirror with carbon dioxide dry ice. Nobody rubs with rags here. (Photo by Chris Gunn):
14. Chamber A is a giant vacuum test chamber that will simulate outer space during testing of the James Webb Telescope, May 20, 2015. (Photo by Chris Gunn):
17. The size of each of the 18 hexagonal segments of the mirror is 1.32 meters from edge to edge. (Photo by Chris Gunn):
18. The mass of the mirror itself in each segment is 20 kg, and the mass of the entire assembled segment is 40 kg. (Photo by Chris Gunn):
19. A special type of beryllium is used for the mirror of the James Webb telescope. It is a fine powder. The powder is placed in a stainless steel container and pressed into a flat shape. Once the steel container is removed, the beryllium piece is cut in half to make two mirror blanks about 1.3 meters across. Each mirror blank is used to create one segment. (Photo by Chris Gunn):
20. Then the surface of each mirror is ground down to give it a shape close to the calculated one. After this, the mirror is carefully smoothed and polished. This process is repeated until the shape of the mirror segment is close to ideal. Next, the segment is cooled to a temperature of −240 °C, and the dimensions of the segment are measured using a laser interferometer. Then the mirror, taking into account the information received, undergoes final polishing. (Photo by Chris Gunn):
21. Once the segment is processed, the front of the mirror is coated with a thin layer of gold to better reflect infrared radiation in the range of 0.6-29 microns, and the finished segment is re-tested at cryogenic temperatures. (Photo by Chris Gunn):
22. Work on the telescope in November 2016. (Photo by Chris Gunn):
23. NASA completed assembly of the James Webb Space Telescope in 2016 and began testing it. This is a photo from March 5, 2017. At long exposures, the techniques look like ghosts. (Photo by Chris Gunn):
26. The door to the same chamber A from the 14th photograph, in which outer space is simulated. (Photo by Chris Gunn):
28. Current plans call for the telescope to be launched on an Ariane 5 rocket in the spring of 2019. When asked what scientists expect to learn from the new telescope, project lead scientist John Mather said, "Hopefully we'll find something that no one knows anything about." (Photo by Chris Gunn):
James Webb is a very complex system that consists of thousands of individual elements. They form the telescope's mirror and its scientific instruments. As for the latter, these are the following devices:
Near-Infrared Camera;
- A device for working in the mid-range of infrared radiation (Mid-Infrared Instrument);
- Near-Infrared Spectrograph;
- Fine Guidance Sensor/Near InfraRed Imager and Slitless Spectrograph.
It is very important to protect the telescope with a screen that will block it from the Sun. The fact is that it is thanks to this screen that the James Webb will be able to detect even the very faint light of the most distant stars. To deploy the screen, a complex system of 180 different devices and other elements was created. Its dimensions are 14*21 meters. “It makes us nervous,” admitted the head of the telescope development project.
The main tasks of the telescope, which will replace Hubble, are: detecting the light of the first stars and galaxies formed after the Big Bang, studying the formation and development of galaxies, stars, planetary systems and the origin of life. Webb will also be able to talk about when and where the reionization of the Universe began and what caused it.
sources
Far from the lights and noise of civilization, on the tops of mountains and in deserted deserts live titans, whose multi-meter eyes are always turned to the stars. Naked Science has selected the 10 largest ground-based telescopes: some have been contemplating space for many years, others have only yet to see the “first light”.
10.Large Synoptic Survey Telescope
Main mirror diameter: 8.4 meters
Location: Chile, peak of Mount Cero Pachon, 2682 meters above sea level
Type: reflector, optical
Although LSST will be located in Chile, it is a US project and its construction is entirely financed by Americans, including Bill Gates (who personally contributed $10 million of the required $400).
The purpose of the telescope is to photograph the entire available night sky every few nights; for this purpose, the device is equipped with a 3.2 gigapixel camera. LSST features a very wide viewing angle of 3.5 degrees (by comparison, the Moon and Sun as seen from Earth occupy just 0.5 degrees). Such capabilities are explained not only by the impressive diameter of the main mirror, but also by the unique design: instead of two standard mirrors, LSST uses three.
Among the scientific goals of the project are the search for manifestations of dark matter and dark energy, mapping the Milky Way, detecting short-term events such as nova or supernova explosions, as well as registering small solar system objects such as asteroids and comets, in particular, near Earth and in the Kuiper Belt.
LSST is expected to see “first light” (a common Western term meaning the moment when the telescope is first used for its intended purpose) in 2020. Construction is currently underway, and the device is scheduled to become fully operational in 2022.
Large Synoptic Survey Telescope, concept / LSST Corporation
9. South African Large Telescope
Main mirror diameter: 11 x 9.8 meters
Location: South Africa, hilltop near the settlement of Sutherland, 1798 meters above sea level
Type: reflector, optical
The largest optical telescope in the southern hemisphere is located in South Africa, in a semi-desert area near the city of Sutherland. A third of the $36 million needed to build the telescope was contributed by the South African government; the rest is divided between Poland, Germany, Great Britain, the USA and New Zealand.
SALT took its first photograph in 2005, shortly after construction was completed. Its design is quite unusual for optical telescopes, but is common among the newer generation of “very large telescopes”: the primary mirror is not single and consists of 91 hexagonal mirrors with a diameter of 1 meter, the angle of each of which can be adjusted to achieve a specific visibility.
Designed for visual and spectrometric analysis of radiation from astronomical objects that are inaccessible to telescopes in the northern hemisphere. SALT employees observe quasars, nearby and distant galaxies, and also monitor the evolution of stars.
There is a similar telescope in the States, it is called the Hobby-Eberly Telescope and is located in Texas, in the town of Fort Davis. Both the mirror diameter and its technology are almost exactly the same as SALT.
South African Large Telescope/Franklin Projects
8. Keck I and Keck II
Main mirror diameter: 10 meters (both)
Location: USA, Hawaii, Mauna Kea mountain, 4145 meters above sea level
Type: reflector, optical
Both of these American telescopes are connected into one system (astronomical interferometer) and can work together to create a single image. The telescopes' unique location in one of the best locations on Earth for astroclimate (the degree to which the atmosphere interferes with the quality of astronomical observations) has made Keck one of the most efficient observatories in history.
The main mirrors of Keck I and Keck II are identical to each other and are similar in structure to the SALT telescope: they consist of 36 hexagonal moving elements. The observatory's equipment makes it possible to observe the sky not only in the optical, but also in the near-infrared range.
In addition to being a major part of the widest range of research, Keck is currently one of the most effective ground-based instruments in the search for exoplanets.
Keck at sunset / SiOwl
7. Gran Telescopio Canarias
Main mirror diameter: 10.4 meters
Location: Spain, Canary Islands, La Palma island, 2267 meters above sea level
Type: reflector, optical
Construction of the GTC ended in 2009, at which time the observatory was officially opened. Even the King of Spain, Juan Carlos I, came to the ceremony. A total of 130 million euros were spent on the project: 90% was financed by Spain, and the remaining 10% was equally divided by Mexico and the University of Florida.
The telescope is capable of observing stars in the optical and mid-infrared range, and has CanariCam and Osiris instruments, which allow GTC to conduct spectrometric, polarimetric and coronagraphic studies of astronomical objects.
Gran Telescopio Camarias / Pachango
6. Arecibo Observatory
Main mirror diameter: 304.8 meters
Location: Puerto Rico, Arecibo, 497 meters above sea level
Type: reflector, radio telescope
One of the most recognizable telescopes in the world, the Arecibo radio telescope has been captured on more than one occasion by movie cameras: for example, the observatory appeared as the site of the final confrontation between James Bond and his antagonist in the film GoldenEye, as well as in the sci-fi film adaptation of Karl's novel Sagan "Contact".
This radio telescope even found its way into video games - in particular, in one of the Battlefield 4 multiplayer maps, called Rogue Transmission, a military clash between two sides takes place right around a structure completely copied from Arecibo.
Arecibo looks really unusual: a giant telescope dish with a diameter of almost a third of a kilometer is placed in a natural karst sinkhole, surrounded by jungle, and covered with aluminum. A movable antenna feed is suspended above it, supported by 18 cables from three high towers at the edges of the reflector dish. The gigantic structure allows Arecibo to catch electromagnetic radiation of a relatively wide range - with wavelengths from 3 cm to 1 m.
Commissioned back in the 60s, this radio telescope has been used in countless studies and has helped make a number of significant discoveries (like the first asteroid discovered by the telescope, 4769 Castalia). Arecibo once even provided scientists with a Nobel Prize: in 1974, Hulse and Taylor were awarded for the first ever discovery of a pulsar in a binary star system (PSR B1913+16).
In the late 1990s, the observatory also began to be used as one of the instruments of the American SETI project to search for extraterrestrial life.
Arecibo Observatory / Wikimedia Commons
5. Atacama Large Millimeter Array
Main mirror diameter: 12 and 7 meters
Location: Chile, Atacama Desert, 5058 meters above sea level
Type: radio interferometer
At the moment, this astronomical interferometer of 66 radio telescopes of 12 and 7 meters in diameter is the most expensive operating ground-based telescope. The USA, Japan, Taiwan, Canada, Europe and, of course, Chile spent about $1.4 billion on it.
Since ALMA's purpose is to study millimeter and submillimeter waves, the most favorable climate for such a device is dry and high-altitude; this explains the location of all six and a half dozen telescopes on the desert Chilean plateau 5 km above sea level.
The telescopes were delivered gradually, with the first radio antenna becoming operational in 2008 and the last in March 2013, when ALMA was officially launched at its full planned capacity.
The main scientific goal of the giant interferometer is to study the evolution of space at the earliest stages of the development of the Universe; in particular, the birth and subsequent dynamics of the first stars.
ALMA / ESO/C.Malin radio telescopes
4. Giant Magellan Telescope
Main mirror diameter: 25.4 meters
Location: Chile, Las Campanas Observatory, 2516 meters above sea level
Type: reflector, optical
Far southwest of ALMA, in the same Atacama Desert, another large telescope is being built, a project of the United States and Australia - GMT. The main mirror will consist of one central and six symmetrically surrounding and slightly curved segments, forming a single reflector with a diameter of more than 25 meters. In addition to a huge reflector, the telescope will be equipped with the latest adaptive optics, which will eliminate as much as possible the distortions created by the atmosphere during observations.
Scientists expect these factors will allow GMT to produce images 10 times clearer than Hubble's, and likely even better than its long-awaited successor, the James Webb Space Telescope.
Among the scientific goals of GMT is a very wide range of research - searching for and photographing exoplanets, studying planetary, stellar and galactic evolution, studying black holes, manifestations of dark energy, as well as observing the very first generation of galaxies. The operating range of the telescope in connection with the stated purposes is optical, near and mid-infrared.
All work is expected to be completed by 2020, but it is stated that GMT can see the “first light” with 4 mirrors as soon as they are introduced into the design. Currently, work is underway to create a fourth mirror.
Giant Magellan Telescope Concept / GMTO Corporation
3. Thirty Meter Telescope
Main mirror diameter: 30 meters
Location: USA, Hawaii, Mauna Kea mountain, 4050 meters above sea level
Type: reflector, optical
The TMT is similar in purpose and performance to the GMT and Hawaiian Keck telescopes. It is on the success of Keck that the larger TMT is based, with the same technology of a primary mirror divided into many hexagonal elements (only this time its diameter is three times larger), and the stated research goals of the project almost completely coincide with the tasks of the GMT, right down to photographing the earliest galaxies almost at the edge of the Universe.
The media quote different project costs, ranging from $900 million to $1.3 billion. It is known that India and China have expressed their desire to participate in TMT and agree to take on part of the financial obligations.
At the moment, a place for construction has been chosen, but there is still opposition from some forces in the Hawaiian administration. Mauna Kea is a sacred site for Native Hawaiians, and many of them are categorically against the construction of an ultra-large telescope.
It is assumed that all administrative problems will be resolved very soon, and construction is planned to be completely completed around 2022.
Thirty Meter Telescope Concept / Thirty Meter Telescope
2. Square Kilometer Array
Main mirror diameter: 200 or 90 meters
Location: Australia and South Africa
Type: radio interferometer
If this interferometer is built, it will become 50 times more powerful astronomical instrument than the largest radio telescopes on Earth. The fact is that SKA must cover an area of approximately 1 square kilometer with its antennas, which will provide it with unprecedented sensitivity.
In structure, SKA is very similar to the ALMA project, however, in size it will significantly exceed its Chilean counterpart. At the moment there are two formulas: either build 30 radio telescopes with antennas of 200 meters, or 150 with a diameter of 90 meters. One way or another, the length over which the telescopes will be placed will be, according to scientists’ plans, 3000 km.
To choose the country where the telescope will be built, a kind of competition was held. Australia and South Africa reached the “finals,” and in 2012 a special commission announced its decision: the antennas would be distributed between Africa and Australia into a common system, that is, the SKA would be placed on the territory of both countries.
The declared cost of the megaproject is $2 billion. The amount is divided between a number of countries: Great Britain, Germany, China, Australia, New Zealand, the Netherlands, South Africa, Italy, Canada and even Sweden. It is expected that construction will be fully completed by 2020.
Artist's rendering of the SKA/SPDO/Swinburne Astronomy Production 5 km core
1. European Extremely Large Telescope
Main mirror diameter: 39.3 meters
Location: Chile, top of Cerro Armazones mountain, 3060 meters
Type: reflector, optical
For a couple of years - perhaps. However, by 2025, a telescope will reach full capacity, which will exceed the TMT by a whole ten meters and which, unlike the Hawaiian project, is already under construction. We are talking about the undisputed leader among the newest generation of large telescopes, namely the European Very Large Telescope, or E-ELT.
Its main almost 40-meter mirror will consist of 798 moving elements with a diameter of 1.45 meters. This, together with the most modern adaptive optics system, will make the telescope so powerful that, according to scientists, it will not only be able to find planets similar to Earth in size, but will also be able to use a spectrograph to study the composition of their atmosphere, which opens up completely new prospects in the study planets outside the solar system.
In addition to searching for exoplanets, E-ELT will study the early stages of cosmic development, try to measure the exact acceleration of the expansion of the Universe, and test physical constants for, in fact, constancy over time; The telescope will also allow scientists to delve deeper than ever before into the formation of planets and their primordial chemistry in the search for water and organics - that is, E-ELT will help answer a number of fundamental scientific questions, including those affecting the origin of life.
The cost of the telescope declared by representatives of the European Southern Observatory (the authors of the project) is 1 billion euros.
European Extremely Large Telescope / ESO/L concept. Calçada
Size comparison of E-ELT and Egyptian pyramids / Abovetopsecret
The first telescope was built in 1609 by Italian astronomer Galileo Galilei. The scientist, based on rumors about the invention of the telescope by the Dutch, unraveled its structure and made a sample, which he used for the first time for space observations. Galileo's first telescope had modest dimensions (tube length 1245 mm, lens diameter 53 mm, eyepiece 25 dioptres), imperfect optical design and 30-fold magnification. But it made it possible to make a whole series of remarkable discoveries: discovering the four satellites of the planet Jupiter, the phases of Venus, spots on The Sun, mountains on the surface of the Moon, the presence of appendages on the disk of Saturn at two opposite points.
More than four hundred years have passed - on earth and even in space, modern telescopes are helping earthlings look into distant cosmic worlds. The larger the diameter of the telescope mirror, the more powerful the optical system.
Multi-mirror telescope
Located on Mount Hopkins, at an altitude of 2606 meters above sea level, in the state of Arizona in the USA. The diameter of the mirror of this telescope is 6.5 meters. This telescope was built back in 1979. In 2000 it was improved. It is called multi-mirror because it consists of 6 precisely adjusted segments that make up one large mirror.
Magellan telescopes
Two telescopes, Magellan-1 and Magellan-2, are located at the Las Campanas Observatory in Chile, in the mountains, at an altitude of 2400 m, the diameter of their mirrors is 6.5 m each. The telescopes began operating in 2002.
And on March 23, 2012, construction began on another more powerful Magellan telescope - the Giant Magellan Telescope; it should go into operation in 2016. In the meantime, the top of one of the mountains was demolished by the explosion to clear a place for construction. The giant telescope will consist of seven mirrors 8.4 meters each, which is equivalent to one mirror with a diameter of 24 meters, for which it has already been nicknamed “Seven Eyes”.
Separated twins Gemini telescopes
Two brother telescopes, each of which is located in a different part of the world. One - "Gemini North" stands on the top of the extinct volcano Mauna Kea in Hawaii, at an altitude of 4200 m. The other - "Gemini South", is located on Mount Serra Pachon (Chile) at an altitude of 2700 m.
Both telescopes are identical, the diameters of their mirrors are 8.1 meters, they were built in 2000 and belong to the Gemini Observatory. Telescopes are located on different hemispheres of the Earth so that the entire starry sky is accessible for observation. Telescope control systems are adapted to work via the Internet, so astronomers do not have to travel to different hemispheres of the Earth. Each of the mirrors of these telescopes is made up of 42 hexagonal fragments that have been soldered and polished. These telescopes are built with the most advanced technologies, making the Gemini Observatory one of the most advanced astronomical laboratories today.
Northern Gemini in Hawaii
Subaru telescope
This telescope belongs to the Japan National Astronomical Observatory. A is located in Hawaii, at an altitude of 4139 m, next to one of the Gemini telescopes. The diameter of its mirror is 8.2 meters. Subaru is equipped with the world's largest “thin” mirror: its thickness is 20 cm, its weight is 22.8 tons. This allows the use of a drive system, each of which transmits its force to the mirror, giving it an ideal surface in any position, which allows you to achieve the best image quality.
With the help of this keen telescope, the most distant galaxy known to date was discovered, located at a distance of 12.9 billion light years. years, 8 new satellites of Saturn, protoplanetary clouds photographed.
By the way, “Subaru” in Japanese means “Pleiades” - the name of this beautiful star cluster.
Japanese Subaru Telescope in Hawaii
Hobby-Eberly Telescope (NO)
Located in the USA on Mount Faulks, at an altitude of 2072 m, and belongs to the MacDonald Observatory. The diameter of its mirror is about 10 m. Despite its impressive size, Hobby-Eberle cost its creators only $13.5 million. It was possible to save the budget thanks to some design features: the mirror of this telescope is not parabolic, but spherical, not solid - it consists of 91 segments. In addition, the mirror is at a fixed angle to the horizon (55°) and can only rotate 360° around its axis. All this significantly reduces the cost of the design. This telescope specializes in spectrography and is successfully used to search for exoplanets and measure the rotation speed of space objects.
Large South African Telescope (SALT)
It belongs to the South African Astronomical Observatory and is located in South Africa, on the Karoo plateau, at an altitude of 1783 m. The dimensions of its mirror are 11x9.8 m. It is the largest in the Southern Hemisphere of our planet. And it was made in Russia, at the Lytkarino Optical Glass Plant. This telescope became an analogue of the Hobby-Eberle telescope in the USA. But it was modernized - the spherical aberration of the mirror was corrected and the field of view was increased, thanks to which, in addition to working in spectrograph mode, this telescope is capable of obtaining excellent photographs of celestial objects with high resolution.
The largest telescope in the world ()
It stands on the top of the extinct Muchachos volcano on one of the Canary Islands, at an altitude of 2396 m. Diameter of the main mirror – 10.4 m. Spain, Mexico and the USA took part in the creation of this telescope. By the way, this international project cost 176 million US dollars, of which 51% was paid by Spain.
The mirror of the Grand Canary Telescope, composed of 36 hexagonal parts, is the largest existing in the world today. Although this is the largest telescope in the world in terms of mirror size, it cannot be called the most powerful in terms of optical performance, since there are systems in the world that surpass it in their vigilance.
Located on Mount Graham, at an altitude of 3.3 km, in Arizona (USA). This telescope belongs to the Mount Graham International Observatory and was built with money from the USA, Italy and Germany. The structure is a system of two mirrors with a diameter of 8.4 meters, which in terms of light sensitivity is equivalent to one mirror with a diameter of 11.8 m. The centers of the two mirrors are located at a distance of 14.4 meters, which makes the telescope's resolving power equivalent to 22 meters, which is almost 10 times greater than that of the famous Hubble Space Telescope. Both mirrors of the Large Binocular Telescope are part of the same optical instrument and together constitute one huge binocular - the most powerful optical instrument in the world at the moment.
William Keck Telescopes
Keck I and Keck II are another pair of twin telescopes. They are located next to the Subaru telescope on the top of the Hawaiian volcano Mauna Kea (height 4139 m). The diameter of the main mirror of each of the Keks is 10 meters - each of them individually is the second largest telescope in the world after the Grand Canary. But this telescope system is superior to the Canary telescope in terms of vigilance. The parabolic mirrors of these telescopes are composed of 36 segments, each of which is equipped with a special computer-controlled support system. Atacama in the Chilean Andes mountain range, on Mount Paranal, 2635 m above sea level. And it belongs to the European Southern Observatory (ESO), which includes 9 European countries.
A system of four 8.2-meter telescopes, and another four auxiliary 1.8-meter telescopes, is equivalent in aperture to one instrument with a mirror diameter of 16.4 meters.
Each of the four telescopes can work separately, obtaining photographs in which stars up to 30th magnitude are visible. Rarely do all telescopes work at once; it is too expensive. More often, each of the large telescopes works in tandem with its 1.8-meter assistant. Each of the auxiliary telescopes can move on rails relative to its “big brother”, occupying the most advantageous position for observing a given object. The Very Large Telescope is the most advanced astronomical system in the world. A lot of astronomical discoveries were made on it, for example, the world's first direct image of an exoplanet was obtained.
The Hubble Space Telescope is a joint project of NASA and the European Space Agency, an automatic observatory in Earth orbit, named after the American astronomer Edwin Hubble. The diameter of its mirror is only 2.4 m, which is smaller than the largest telescopes on Earth. But due to the lack of atmospheric influence, the resolution of the telescope is 7 - 10 times greater than a similar telescope located on Earth. Hubble is responsible for many scientific discoveries: the collision of Jupiter with a comet, images of the relief of Pluto, auroras on Jupiter and Saturn...
But the price one has to pay for Hubble's achievements is very high: the cost of maintaining a space telescope is 100 times higher than a ground-based reflector with a 4-meter mirror.
Hubble telescope in earth orbit
