An overview of the most powerful optical telescopes in the world today. The first part is the diameter of the main mirror up to 6 meters ..
In this two-part survey, you will find almost all optical telescopes in the world with a primary mirror over 6 meters in diameter, and definitely all over 8 meters in diameter.
As you know, the diameter of the lens of an optical device is the main characteristic of this device, since the larger this diameter, the more light the lens will collect, respectively, the fainter objects can be observed. In addition, with an increase in the diameter of the objective, the resolution of the telescope increases, that is, its ability to see individually very closely spaced stars.
For starters, you can see the location of the most powerful telescopes on a map of the world.
Map of the location of the largest telescopes in the world.
On the map yellow The names of the observatories to which the telescope belongs are indicated, in white - the names of the telescopes already existing at the moment, in green - the approved projects of super-powerful telescopes (the construction of some of them has already begun). The diameter of the main mirror of the telescope and the number of telescopes, if there are several, are indicated in brackets.
Dome of the Anglo-Australian Telescope (AAT). View of Warrumbangle National Park. This is a small telescope by modern standards. I only added it to this list to fill a gap in the above telescope map, so I'll mention it briefly.
The diameter of the main mirror is 3.9 m. Observations began in 1975. Located in Australia, New South Wales, in the Warrumbungle National Park. More precisely, on Mount Siding Spring (height 1165 m) on the territory of the Siding Spring Observatory, which belongs to Australian Astronomical Observatory (AAO).
With the help of this tool, survey photography of the southern hemisphere of the sky is mainly carried out, searches for near-earth objects, studies of gas flows around, the search for the oldest stars of the Milky Way, etc.
On August 7, 2006, the brightest comet of the last few decades was discovered by Robert McNaught on this instrument. Comet McNaught (C / 2006 P1) reached 6th magnitude in January 2007 and the inhabitants of the southern hemisphere could observe it even during the day with the naked eye.
Hale telescope dome at night. The diameter of the main mirror is 5.08 m. Mount Palomar Astronomical Observatory on Mount Palomar (height 1700 meters) about 200 km. from the city of Pasadena (USA, California).
Its construction began in 1936, but due to the Second World War, work was delayed until 1948. For over 20 years, until the appearance of BTA-6 in 1976, it remained the largest telescope in the world.
A bit of history .. This telescope owes its appearance to a real fan of astronomy named George Ellery Hale, who has been engaged in the creation of large (for that time) telescopes almost all his life. In 1908, on Mount Wilson (California), he installed a 1.5-meter telescope, in 1917 he built a 2.5-meter telescope there, which remained the largest in the world until 1948. But he set out to build another 2 times a larger telescope. In 1928, he received $ 6 million from Rockefeller Financial Fund. The primary mirror was entrusted to Corning Glass Works using new glass. Pyrex with improved characteristics. The construction of the observatory began in 1936, but due to the Second World War, work was delayed until 1948. George Hale himself died in 1938, not having lived 10 years before the telescope named after him saw the "first light".
This instrument is still actively used by scientists to study the universe, of course, in a modernized form - it was equipped with a modern optical and infrared sensor and adaptive optics system,which significantly reduces the distortion of the light of stars introduced by the movements of the earth's atmosphere .
Large Telescope Alt-azimuth (BTA-6).
The BTA-6 dome opens up like a visor on a knight's helmet, and does not move apart in different directions, like in other telescopes. Diameter - 6.05 m. Located in the Caucasus, in Karachay-Cherkessia near the village of Nizhny Arkhyz on Mount Semiruchi (height 2070 m). Zelenchuk observatory. First observations - 1975. He managed to stay the largest in the world until 1993, when the Americans built a telescope. Keck I in Hawaii.
In fact, the construction of BTA-6 is another act of the former USSR's gigantomania.
The history of the creation of BTA-6 ..
In the early 60s, Soviet scientists received a "special task" from the government - to create a telescope larger than that of the Americans (Hale telescope - 5 m). They considered that a meter more would be enough, since the Americans generally considered it senseless to create solid mirrors more than 5 meters in size due to deformation under their own weight.
The Soviet optical industry of those times was not designed to solve such problems, therefore, to create a 6-meter mirror, a plant was specially built in Lytkarino near Moscow on the basis of a small workshop for the production of mirror reflectors.
The blank for such a mirror weighs 70 tons, the first few were "screwed up" because of the rush, as they had to cool for a very long time in order not to crack. "Successful" workpiece cooled down for 2 years and 19 days. Then, during its grinding, 15,000 carats of diamond tools were produced and almost 30 tons of glass were "erased". The fully finished mirror now weighs 42 tons.
The delivery of the mirror to the Caucasus is worth a separate mention .. First, a dummy of the same size and weight was sent to the destination, some adjustments were made to the route - 2 new river ports were built, 4 new bridges and 6 existing ones were strengthened and expanded, several hundred kilometers were laid new roads with perfect coverage.
The mechanical parts of the telescope were created at the Leningrad Optical and Mechanical Plant. The total mass of the telescope was 850 tons.
But despite all efforts, the American Hale BTA-6 telescope failed to "surpass" in quality (that is, in resolution). Partly due to defects in the main mirror (the first pancake is still lumpy), partly due to the worse climatic conditions at its location. Such a failure gave rise to ridicule from the Americans .. "The Russians have a tsar cannon that does not fire, a tsar bell that does not ring, and a telescope that does not see." 
The installation in 1978 of a new mirror, already the third in a row, significantly improved the situation, but the weather conditions remained the same. In addition, the work is complicated by the too high sensitivity of the solid mirror to minor temperature fluctuations. “Doesn't see” - this is of course loudly said, until 1993 BTA-6 remained the world's largest telescope, and it is the largest in Eurasia to this day. With the new mirror, it was possible to achieve a resolution almost like that of the Hale, and the "penetrating power", that is, the ability to see faint objects in the BTA-6 is even greater (after all, the diameter is a whole meter larger).
New life for BTA-6.
In 2007, it was decided to radically restore and modernize the BTA-6. The main mirror was removed and sent to the plant in Lytkarino, and a spare one was temporarily installed in its place (which will later also be restored).
Restoration of the main mirror of the BTA-6 telescope. Lytkarino optical glass plant Over the past decades, the technology has stepped far forward and now LZOS (Lytkarinsky Optical Glass Plant) can create an almost perfect mirror from an old worn-out mirror, three (!) Times superior to the old one in optical characteristics. The crisis made it difficult to finance the work, so at the time of this writing (2012) the new mirror is not yet ready. Presumably this will happen in mid-2013.
With the new mirror, as well as with the modern optical receivers already used on BTA-6 (CCDs cooled with liquid nitrogen to reduce intrinsic noise), this telescope should enter the top ten telescopes in the world in terms of its characteristics. Most likely not for long, since time, as always, moves forward.
Large Zenith Telescope (LZT).
Large Anti-Aircraft Telescope. Located near Vancouver (Canada). Belongs University of British Columbia. The diameter of the main mirror is 6 meters, it is located at a height of 395 m, the first light "saw" in 2004.
The world's largest liquid mirror. A bowl with 28 liters of mercury. An unusual telescope. Its main mirror is a rotating bowl of a mercury-based ferromagnetic liquid with a diameter of 6 meters. Moreover, the bowl rotates on an air cushion to reduce vibration to zero.
The LZT telescope tower looks like a regular barn with an opening at the top, as it does not need a rotating dome. The most economical super telescope project. The mirror makes one revolution in 8.5 seconds, the rotation gives it a perfect parabolic surface, which is very difficult to obtain in the manufacture of solid mirrors. Therefore, the creation of this telescope cost a "ridiculous" figure - only $ 500,000, which is ten times less than would have to be spent on a telescope with the same mirror diameter, but solid-state.
In addition, this mirror is equipped with a unique adaptive system - there are 91 electromagnets under the mirror, which, under the control of a computer, impart minor distortions to the surface of the ferromagnetic liquid. Precisely calculated distortions compensate for the interference introduced by the movement of the earth's atmosphere, which significantly increases the clarity of the image obtained by the telescope.
The main disadvantage of the Large Zenith Telescope is that, like other telescopes with a liquid mirror, it can only look at the zenith. Indeed, after all, the mirror must rotate strictly in horizontal plane... But the earth rotates, besides, the movement of the secondary mirror allows the telescope's field of view to expand, therefore, during the year, most of the sky falls into the LZT's field of view.
In addition to studying stars and galaxies, this telescope also tracks the movement of "space debris".
A story about more modern largest telescopes in the world in
Over the past 20-30 years, a satellite dish has become an integral part of our life. Many modern cities have access to satellite television. Satellite dishes became massively popular in the early 1990s. For these dish antennas, used as radio telescopes to receive information from different parts of the planet, size does matter. Here are the ten largest telescopes on Earth, located in the largest observatories in the world
10 Stanford Satellite Telescope, USA
Diameter: 150 feet (46 meters)
Located in the foothills of Stanford, California, a radio telescope known as the landmark dish. It is visited by approximately 1,500 people every day. Built by Stanford Research Institute in 1966, the 150-foot-diameter (46 meters) radio telescope was originally designed to study the chemical composition of our atmosphere, but, with such a strong radar antenna, was later used to communicate with satellites and spacecraft.
9 Algonquin Observatory, Canada
Diameter: 150 feet (46 meters)
This observatory is located in Algonquin Provincial Park in Ontario, Canada. The main centerpiece of the observatory is a 150-foot (46 m) parabolic dish, which became known in 1960 during the early technical tests of the VLBI. The VLBI allows for simultaneous observations of many telescopes that are interconnected.
8 LMT Large Telescope, Mexico
Diameter: 164 feet (50 meters)
The LMT Large Telescope is a relatively recent addition to the list of the largest radio telescopes. Built in 2006, this 164-foot (50 m) instrument is the best telescope for sending radio waves in its own frequency range. Providing astronomers with valuable information regarding stellar formation, the LMT is located in the Negra mountain range - the fifth highest mountain in Mexico. This combined Mexican and American project cost $ 116 million.
7 Parks Observatory, Australia
Diameter: 210 feet (64 meters)
Completed in 1961, Parks Observatory in Australia was one of several used to transmit television signals in 1969. The observatory provided NASA with valuable information during their lunar missions, transmitting signals and providing necessary assistance when our only natural satellite was on the Australian side of the Earth. More than 50 percent of known pulsars -neutron stars - were discovered in Parks.
6 Aventurine Communication Complex, USA
Diameter: 230 feet (70 meters)
Known as the Aventurine Observatory, this complex is located in the Mojave Desert, California. This is one of 3 such complexes - the other two are located in Madrid and Canberra. Aventurine is known as the antenna of Mars, which is 230 feet (70 m) in diameter. This highly sensitive radio telescope - which was actually modeled and later upgraded to be larger than the saucer from Australia's Parks Observatory - and provide more information to aid in the mapping of quasars, comets, planets, asteroids and many other celestial bodies. The aventurine complex has also proven its worth in the search for high-energy neutrino transfers on the moon.
5 Evpatoria, Radio Telescope RT-70, Ukraine
Diameter: 230 feet (70 meters)
The Yevpatoria telescope was used to detect asteroids and space debris. It was from here that on October 9, 2008, a signal was sent to the planet Gliese 581c called "Super Earth". If Gliese 581 is inhabited by sentient beings, maybe they will send us a signal back! However, we will have to wait until the message reaches the planet in 2029.
4 Lovell Telescope, UK
Diameter: 250 feet (76 meters)
Lovell is a United Kingdom Telescope located at the Jordell Bank Observatory in the northwest of England. Built in 1955, it was named after one of its creators, Bernard Lovell. Among the telescope's most famous accomplishments was the confirmation of the existence of a pulsar. The telescope also contributed to the discovery of quasars.
3 Effelsberg Radio Telescope in Germany
The Effelsberg radio telescope is located in western Germany. Built between 1968 and 1971, the telescope is at the disposal of the Max Planck Institute for Radio Astronomy, Bonn. Equipped to observe pulsars, star formations and the nuclei of distant galaxies, Effelsberg is one of the world's most important super-strong telescopes.
2 Green Telescope Bank, USA
Diameter: 328 feet (100 meters)
Located in West Virginia, in the heart of the United States' National Quiet Zone, the Green Bank Telescope is an area of \u200b\u200brestricted or prohibited radio transmissions that greatly assists the telescope in reaching its highest potential. The telescope, which was completed in 2002, took 11 years to build.
1. Arecibo Observatory, Puerto Rico
Diameter: 1,001 feet (305 meters)
The largest telescope on Earth is by far the Arecibo Observatory near the city of the same name in Puerto Rico. Operated by SRI International - a research institute from Stanford University, the Observatory is involved in radio astronomy, radar observations solar system and in the study of the atmospheres of other planets. The huge plate was built in 1963.
Continuation of the survey of the largest telescopes in the world, begun in
The diameter of the main mirror is over 6 meters.
See also the location of the largest telescopes and observatories on
Multi-mirror Telescope
Tower of the Multi-Mirror Telescope with Comet Hale-Bopp in the background. Mount Hopkins (USA).Multiple Mirror Telescope (MMT). Located in the observatory Mount Hopkins in Arizona, (USA) on Mount Hopkins at an altitude of 2606 meters. The mirror diameter is 6.5 meters. Started working with a new mirror on May 17, 2000.
In fact, this telescope was built in 1979, but then its lens was made of six mirrors of 1.8 meters, which is equivalent to one mirror with a diameter of 4.5 meters. At the time of construction, it was the third most powerful telescope in the world after BTA-6 and Hale (see the previous post).
As the years passed, the technology improved, and already in the 90s it became clear that with a relatively small amount of investment, it was possible to replace 6 separate mirrors with one large one. Moreover, this will not require significant changes in the design of the telescope and tower, and the amount of light collected by the lens will increase by as much as 2.13 times.
Multiple Mirror Telescope before (left) and after (right) reconstruction. This work was completed by May 2000. A 6.5 meter mirror was installed, as well as a system active and adaptive optics. It is not a single one, but a segmented mirror, consisting of precisely fitted 6-angle segments, so that the name of the telescope did not have to be changed. Is that sometimes they began to add the prefix "new".
The new MMT, in addition to seeing 2.13 times fainter stars, has a 400 times larger field of view. So, the work was clearly not in vain.
Active and adaptive optics
System active optics allows, with the help of special drives installed under the main mirror, to compensate for the deformation of the mirror when the telescope rotates.
Adaptive opticsby tracking the distortion of the light of artificial stars in the atmosphere created by lasers and the corresponding curvature of the auxiliary mirrors, compensates for atmospheric distortion.
Magellan Telescopes
Magellan's telescopes. Chile. Located at a distance of 60 m from each other, they can operate in the interferometer mode. Magellan telescopes - two telescopes - "Magellan-1" and "Magellan-2", with mirrors 6.5 meters in diameter. Located in Chile, at the observatory "Las Campanas" at an altitude of 2400 km. Besides common name each of them also has its own name - the first, named after the German astronomer Walter Baade, began work on September 15, 2000, the second, named after Landon Clay, an American philanthropist, entered service on September 7, 2002.
Las Campanas Observatory is located two hours by car from La Serena. This is a very convenient place for the location of the observatory, both due to the rather high altitude above sea level, and due to the distance from settlements and dust sources. Two twin telescopes Magellan-1 and Magellan-2, operating both separately and in the interferometer mode (as a whole), are currently the main instruments of the observatory (there is still one 2.5-meter and two 1- meter reflector).
Giant Magellanic Telescope (GMT). Project. Implementation date - 2016.On March 23, 2012, the construction of the Giant Magellanic Telescope (GMT) began with a spectacular explosion from the top of one of the nearby mountains. The top of the mountain has been torn down to make way for a new telescope, due to begin work in 2016.
The Giant Magellan Telescope (GMT) will consist of seven mirrors of 8.4 meters each, which is equivalent to one mirror with a diameter of 24 meters, for which it has already been nicknamed "Semiglaz". Of all the projects of huge telescopes, this one (for 2012) is the only one whose implementation has moved from the planning stage to practical construction.
Gemini telescopes
Gemini North Telescope Tower. Hawaii. Mauna Kea volcano (4200 m). 
Gemini South. Chile. Mount Serra Pachon (2700 m). Also two twin telescopes, only each of the "brothers" is located in a different part of the world. The first - "Gemini North" - in Hawaii, on the top of the extinct volcano Mauna Kea (altitude 4200 m). The second - "Gemini South", is located in Chile on the Serra Pachon mountain (height 2700 m).
Both telescopes are identical, their mirrors have diameters of 8.1 meters, they were built in 2000 and belong to the Gemini Observatory, operated by a consortium of 7 countries.
Since the telescopes of the observatory are located in different hemispheres of the Earth, the entire starry sky is available for observation at this observatory. In addition, telescope control systems are adapted for remote operation via the Internet, so astronomers do not have to make long journeys from one telescope to another.
North Gemini. View inside the tower. Each of the mirrors of these telescopes is made up of 42 hexagonal pieces that have been soldered and polished. The telescopes use systems of active (120 drives) and adaptive optics, a special system of silvering mirrors, which provides a unique image quality in the infrared range, a system of multi-object spectroscopy, in general, "full stuffing" of the most modern technologies. All this makes the Gemini Observatory one of the most advanced astronomical laboratories today.
Telescope "Subaru"
Japanese telescope "Subaru". Hawaii. "Subaru" in Japanese means "Pleiades", the name of this beautiful star cluster is known by everyone, even a beginner, a fan of astronomy. Subaru telescope belongs Japan National Astronomical Observatory, but located in Hawaii, on the territory of the Observatory Mauna Kea, at an altitude of 4139 m, that is, in the vicinity of the northern Gemini. The diameter of its main mirror is 8.2 meters. I saw the "first light" in 1999.
Its main mirror is the world's largest single-piece telescope mirror, but it is relatively thin - 20 cm, its weight is "only" 22.8 tons. This makes it possible to effectively use the most accurate active optics system of 261 drives. Each actuator transmits its force to the mirror, giving it a perfect surface in any position, which allows you to achieve almost a record image quality to date.
A telescope with such characteristics is simply obliged to "see" hitherto unknown miracles in the universe. Indeed, with its help, the most distant galaxy known to date (distance 12.9 billion light years) was discovered, the largest structure in the universe - an object 200 million light years long, probably the embryo of a future cloud of galaxies, 8 new satellites of Saturn .. This telescope also "distinguished itself" in the search for exoplanets and photographing protoplanetary clouds (in some images, even clumps of protoplanets are distinguishable).
Hobby-Eberley Telescope
McDonald Observatory. Hobby-Eberly Telescope. USA. Texas. The Hobby-Eberly Telescope (HET) - located in the USA, in McDonald Observatory. The observatory is located on Mount Folks, at an altitude of 2072 m. Start of work - December 1996. The effective aperture of the main mirror is 9.2 m. (In fact, the mirror has a size of 10x11 m, but the light receiving devices located in the focal unit cut off the edges to a diameter of 9.2 meters.)
Despite the large diameter of the main mirror of this telescope, Hobby-Eberly can be attributed to low-budget projects - it cost only $ 13.5 million. This is not much, for example the same "Subaru" cost its creators about $ 100 million.
The budget was saved thanks to several design features:
- Firstly, this telescope was conceived as a spectrograph, and for spectral observations a spherical rather than a parabolic main mirror is sufficient, which is much easier and cheaper to manufacture.
- Secondly, the main mirror is not integral, but composed of 91 identical segments (since its shape is spherical), which also greatly reduces the cost of the design.
- Thirdly, the main mirror is at a fixed angle to the horizon (55 °) and can only rotate 360 \u200b\u200b° around its axis. This eliminates the need to equip the mirror with a complex system of shape correction (active optics), since its tilt angle does not change.
But despite such a fixed position of the main mirror, this optical instrument covers 70% of the celestial sphere due to the movement of an 8-ton light receiver module in the focal region. After aiming at the object, the main mirror remains stationary, and only the focal node moves. The time of continuous object tracking is from 45 minutes at the horizon to 2 hours in the upper part of the sky.
Due to its specialization (spectrography), the telescope is successfully used, for example, to search for exoplanets or to measure the rotation speed of space objects.
Large South African Telescope
Large South African Telescope. SALT. SOUTH AFRICA. Southern African Large Telescope (SALT) - located in South Africa in South African Astronomical Observatory 370 km northeast of Cape Town. The observatory is located on the dry Karu plateau, at an altitude of 1783 m. First light - September 2005. The dimensions of the mirror are 11x9.8 m.
The government of South Africa, inspired by the cheapness of the HET telescope, decided to build its analogue in order to keep up with other developed countries in the study of the universe. By 2005, construction was completed, the entire project budget was 20 million US dollars, half of which went to the telescope itself, the other half to the building and infrastructure.
Since the SALT telescope is almost a complete analogue of HET, everything that has been said above about HET applies to it as well.
But, of course, it was not without some modernization - it mainly concerned the correction of the spherical aberration of the mirror and an increase in the field of view, due to which, in addition to working in the spectrograph mode, this telescope is able to obtain excellent photographs of objects with a resolution of up to 0.6 ″. This device is not equipped with adaptive optics (probably the South African government did not have enough money).
By the way, the mirror of this telescope, the largest in the southern hemisphere of our planet, was made at the Lytkarinsky Optical Glass Plant, that is, on the same as the mirror of the BTA-6 telescope, the largest in Russia.
The largest telescope in the world
Large Canary Telescope
Tower of the Great Canary Telescope. Canary Islands (Spain). The Gran Telescopio CANARIAS (GTC) - located at the top of the extinct volcano Muchachos on the island of La Palma in the north-west of the Canary archipelago, at an altitude of 2396 m. The diameter of the main mirror is 10.4 m (area - 74 sq. M.). Start of work - July 2007.
The observatory is called Roque de los Muchachos. Spain, Mexico and the University of Florida contributed to the creation of GTC. This project cost US $ 176 million, of which 51% was paid by Spain.
Mirror of the Great Canary Telescope with a diameter of 10.4 meters, composed of 36 hexagonal segments - the largest existing in the world today (2012). Made by analogy with Keck telescopes.
..and it looks like GTC will hold the lead in this parameter until a telescope with a mirror 4 times larger in diameter is built in Chile on Mount Armazones (3,500 m) - "Extremely Large Telescope"(European Extremely Large Telescope), or Hawaii will not build a 30-meter telescope(Thirty Meter Telescope). Which of these two competing projects will be implemented faster is unknown, but according to the plan, both of them should be completed by 2018, which looks more doubtful for the first project than for the second.
Of course, there are also 11 meter mirrors for the HET and SALT telescopes, but as mentioned above, out of 11 meters, only 9.2 meters are effectively used.
Although it is the largest telescope in the world in terms of mirror size, it cannot be called the most powerful in terms of optical performance, as there are multi-mirror systems in the world that are superior to GTC in terms of their vigilance. We will talk about them further.
Large Binocular Telescope
Tower of the Large Binocular Telescope. USA. Arizona. (Large Binocular Telescope - LBT) - located on Mount Graham (3.3 km.) In the state of Arizona (USA). Belongs to the International Observatory Mount Graham. Its construction cost $ 120 million, the money was invested by the USA, Italy and Germany. LBT is an optical system of two mirrors with a diameter of 8.4 meters, which is equivalent in light sensitivity to one mirror with a diameter of 11.8 m. In 2004 LBT “opened one eye”, in 2005 a second mirror was installed. But only since 2008 it started working in binocular mode and in interferometer mode.
Large Binocular Telescope. Scheme. The centers of the mirrors are at a distance of 14.4 meters, which makes the telescope's resolution equivalent to 22 meters, which is almost 10 times that of the famous space hubble telescopeand. The total area of \u200b\u200bthe mirrors is 111 sq. m., that is, as much as 37 sq. m. more than the GTC.
Of course, if we compare the LBT with multi-telescope systems such as the Keck telescopes or VLT, which can operate in the interferometer mode with larger bases (distance between the components) than the LBT and, accordingly, give even greater resolution, then the Large Binocular Telescope will be inferior to them in terms of this indicator. But it is not entirely correct to compare interferometers with ordinary telescopes, since they cannot give photographs of extended objects at this resolution.
Since both LBT mirrors send light to a common focus, that is, they are part of the same optical device, unlike telescopes, which will be discussed later, plus the presence of this giant binoculars the latest systems active and adaptive optics, it can be argued that The Large Binocular Telescope is the most advanced optical instrument in the world at the moment.
Telescopes by William Keck
Telescope towers by William Keck. Hawaii. Keck Iand Keck II - another pair of twin telescopes. Location - Hawaii Observatory Mauna Kea, on the top of the Mauna Kea volcano (height 4139 m.), that is, in the same place as the Japanese telescope "Subaru" and "Gemini North". The inauguration of the first Keck took place in May 1993, the second in 1996.
The diameter of the main mirror of each of them is 10 meters, that is, each of them individually is the second largest telescope in the world after the Great Canary, just slightly inferior to the latter in size, but surpassing it in "vigilance", due to the ability to work in pairs, and also a higher location above sea level. Each of them is capable of giving an angular resolution of up to 0.04 arc seconds, and working together in the interferometer mode with a base of 85 meters - up to 0.005 ″.
The parabolic mirrors of these telescopes are composed of 6 hexagonal segments, each of which is equipped with a special computer-controlled support system. The first photograph was taken back in 1990, when the first Keck had only 9 segments installed, it was a photograph spiral galaxy NGC1232.
Very Large Telescope
Very Large Telescope. Chile. Very Large Telescope (VLT). Location - Mount Paranal (2635 m.) In the Atacama Desert in the Chilean Andes mountain range. Accordingly, the observatory is called Paranal, it belongs to European Southern Observatory (ESO), which includes 9 European countries.
The VLT is a system of four 8.2 meter telescopes and four additional 1.8 meter telescopes. The first of the main instruments entered service in 1999, the last in 2002, and later auxiliary ones. After that, for several more years, work was carried out to adjust the interferometric mode, the instruments were connected first in pairs, then all together.
At present, telescopes can operate in the mode of a coherent interferometer with a base of about 300 meters and a resolution of up to 10 microseconds of an arc. Also, in the mode of a single incoherent telescope, collecting light into one receiver through a system of underground tunnels, while the luminosity of such a system is equivalent to one device with a mirror diameter of 16.4 meters.
Naturally, each of the telescopes can work separately, obtaining photographs of the starry sky with an exposure of up to 1 hour, in which stars up to the 30th magnitude are visible.
The first direct photo of an exoplanet, next to the star 2M1207 in the constellation Centaurus. Received from VLT in 2004. The material and technical equipment of the Paranal Observatory is the most advanced in the world. It is more difficult to say which instruments for observing the universe are not here than to list which ones are. These are spectrographs of all kinds, as well as receivers of radiation from the ultraviolet to infrared range, as well as all possible types.
As mentioned above, the VLT system can operate as a single unit, but this is a very expensive mode and is therefore rarely used. More often, for interferometric operation, each of the large telescopes is paired with its 1.8 meter Auxiliary Telescope (AT). Each of the auxiliary telescopes can move along the rails relative to its "boss", occupying the most favorable position for observing this object.
All this does VLT the most powerful optical system in the worldand ESO, the most advanced astronomical observatory in the world, is a veritable paradise for astronomers. A lot of astronomical discoveries were made on the VLT, as well as previously impossible observations, for example, the world's first direct image of an exoplanet was obtained.
The James Webb Telescope is an orbiting infrared observatory to replace the famous Hubble Space Telescope.
This is a very complex mechanism. Work on it has been going on for about 20 years! "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.
We'll see?
1. 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 is a test conducted on March 30, 2012 to investigate the ability to withstand the cold temperatures of space. (Photo by Chris Gunn | NASA):
2. "James Webb" will have a composite mirror 6.5 meters in diameter with a collecting surface area of \u200b\u200b25 m². Is it a lot, or a little? (Photo by Chris Gunn):
3. Compare with Hubble. Mirror "Hubble" (left) and "Webb" (right) in 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 scheduled for 2007, 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 complete main composite mirror was assembled only in February 2016. (Photo by Chris Gunn):
7. The sensitivity of a telescope and its resolution are directly related to the size of the area of \u200b\u200bthe mirror that collects light from objects. Scientists and engineers have determined that the minimum diameter of the primary mirror should be 6.5 meters in order to measure light from the most distant galaxies.
Simply making a mirror like the Hubble telescope mirror but larger was unacceptable because its mass would be too large to launch the telescope into space. A team of scientists and engineers needed to find a solution so that the new mirror had 1/10 the mass of the Hubble telescope mirror per unit area. (Photo by Chris Gunn):
8. Not only in our country everything rises in price from the initial estimate. Thus, the cost of the James Webb telescope exceeded the initial calculations by at least 4 times. It was planned that the telescope will cost $ 1.6 billion and will be launched in 2011, but according to new estimates, the cost may be 6.8 billion, while the launch will take place no earlier than 2018. (Photo by Chris Gunn):
9. This is a near infrared spectrograph. It will analyze the spectrum of sources, which will allow obtaining 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 practically equal to the temperature of the Earth's surface), located further than 12 AU. e. from their stars, and distant from the Earth at a distance of up to 15 light years. More than two dozen stars closest to the Sun will fall into the zone of detailed observation. Thanks to "James Webb" a real breakthrough in exoplanetology is expected - the capabilities of the telescope will be sufficient not only to detect exoplanets themselves, but even satellites and spectral lines of these planets.
11. Engineers are testing in the chamber. telescope lifting system, September 9, 2014. (Photo by Chris Gunn):
12. Study of mirrors, September 29, 2014. The hexagonal shape of the segments was not chosen by chance. It has a high fill factor and sixth order symmetry. A high fill factor means the segments fit together without gaps. Due to the 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 - for the most compact focusing of light on the detectors. An oval mirror, for example, would give 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 here with rags. (Photo by Chris Gunn):
14. Chamber A is a giant vacuum test chamber that will simulate outer space when testing the James Webb Telescope, May 20, 2015. (Photo by Chris Gunn):
17. Each of the 18 hexagonal mirror segments measures 1.32 meters 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 segment as an assembly 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 mold. After the steel container is removed, a piece of beryllium 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 grinded to give a shape close to the calculated one. After that, the mirror is carefully smoothed and polished. This process is repeated until the shape of the mirror segment is close to ideal. The segment is then cooled to a temperature of −240 ° C, and the segment dimensions are measured using a laser interferometer. Then the mirror, taking into account the information received, undergoes a final polishing. (Photo by Chris Gunn):
21. Upon completion of the segment processing, the front part of the mirror is coated with a thin layer of gold for better reflection of infrared radiation in the 0.6-29 µm range, 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 and testing of the James Webb Space Telescope in 2016. This is a snapshot from March 5, 2017. On long exposure, the techniques look like ghosts. (Photo by Chris Gunn):
26. The door to the very chamber A from the 14th photo, in which outer space is modeled. (Photo by Chris Gunn):
28. Current plans call for the telescope to be launched by an Ariane 5 rocket in spring 2019. Asked about what scientists expect to learn with the new telescope, project lead researcher John Mather said, "I hope we find something that no one knows anything about." UPD. The launch of the James Webb Telescope has been postponed to 2020. (Photo by Chris Gunn).
March 23rd, 2018
The James Webb Telescope is an orbiting infrared observatory to replace the famous Hubble Space Telescope. "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! Initially, the launch was scheduled for 2007, 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 complete main composite mirror was assembled only in February 2016. Then they announced the launch in 2018, but according to the latest information, the telescope will be launched using the 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 operability of many elements and the already assembled structure during each stage. Beginning in mid-July, the telescope began to be tested for operability at ultra-low temperatures - from 20 to 40 degrees Kelvin. For several weeks, the operation of the 18 main mirror sections of the telescope was tested in order to make sure that they can work as a whole. The diameter of the composite telescope mirror is 6.5 meters.
Later, after it turned out that everything was fine, scientists tested the orientation system, 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 have made sure that the telescope will work quite correctly in space.
The James Webb telescope is to be placed in a halo orbit at the L2 Lagrange point of the Sun-Earth system. And it's cold in space. Shown here is a test conducted on March 30, 2012 to investigate the ability to withstand the cold temperatures of space. (Photo by Chris Gunn | NASA):
in 2017, the James Webb telescope was again held in extreme conditions. He was placed in a cell where 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 the conditions of open space.
“We are now convinced that NASA and agency partners have built an excellent telescope and science toolkit,” said Bill Ochs, Project Manager for James Webb at the Goddard Space Flight Center.
James Webb will have a 6.5 meter diameter composite mirror with a collecting surface area of \u200b\u200b25 m². Is it a lot, or a little? (Photo by Chris Gunn):
But that's not all, the telescope still has many tests to go before it is considered fully ready for shipment. Recent tests have shown that the device can operate in a vacuum at ultra-low temperatures. It is these 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. On board this giant, the telescope will fly to Los Angeles, where it will be finally assembled with a sunscreen. Scientists will then check whether the entire system works with such a screen, and whether the device can withstand vibration and stress during flight.
Compare with Hubble. Mirror "Hubble" (left) and "Webb" (right) in 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 scheduled for 2007, 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 complete main composite mirror was assembled only in February 2016. (Photo by Chris Gunn):
7. The sensitivity of a telescope and its resolution are directly related to the size of the area of \u200b\u200bthe mirror that collects light from objects. Scientists and engineers have determined that the minimum diameter of the primary mirror should be 6.5 meters in order to measure light from the most distant galaxies.
Simply making a mirror like the Hubble telescope mirror but larger was unacceptable because its mass would be too large to launch the telescope into space. A team of scientists and engineers needed to find a solution so that the new mirror had 1/10 the mass of the Hubble telescope mirror per unit area. (Photo by Chris Gunn):
8. Not only in our country everything rises in price from the initial estimate. Thus, the cost of the James Webb telescope exceeded the initial calculations by at least 4 times. It was planned that the telescope will cost $ 1.6 billion and will be launched in 2011, however, according to new estimates, the cost may be 6.8 billion, but there is already information about exceeding this limit up to 10 billion (Photo by Chris Gunn):
9. This is a near infrared spectrograph. It will analyze the spectrum of sources, which will allow obtaining 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 practically equal to the temperature of the Earth's surface), located further than 12 AU. e. from their stars, and distant from the Earth at a distance of up to 15 light years. More than two dozen stars closest to the Sun will fall into the zone of detailed observation. Thanks to James Webb, a real breakthrough in exoplanetology is expected - the capabilities of the telescope will be sufficient not only to detect exoplanets themselves, but even satellites and spectral lines of these planets.
11. Engineers are testing in the chamber. telescope lifting system, September 9, 2014. (Photo by Chris Gunn):
12. Study of mirrors, September 29, 2014. The hexagonal shape of the segments was not chosen by chance. It has a high fill factor and sixth order symmetry. A high fill factor means the segments fit together without gaps. Due to the 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 - for the most compact focusing of light on the detectors. An oval mirror, for example, would give 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 here with rags. (Photo by Chris Gunn):
14. Chamber A is a giant vacuum test chamber that will simulate outer space when testing the James Webb Telescope, May 20, 2015. (Photo by Chris Gunn):
17. Each of the 18 hexagonal mirror segments measures 1.32 meters 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 segment as an assembly 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 mold. After the steel container is removed, a piece of beryllium 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 grinded to give a shape close to the calculated one. After that, the mirror is carefully smoothed and polished. This process is repeated until the shape of the mirror segment is close to ideal. The segment is then cooled to a temperature of −240 ° C, and the segment dimensions are measured using a laser interferometer. Then the mirror, taking into account the information received, undergoes a final polishing. (Photo by Chris Gunn):
21. Upon completion of the segment processing, the front of the mirror is coated with a thin layer of gold for better reflection of infrared radiation in the 0.6-29 µm range, and the finished segment is retested at cryogenic temperatures. (Photo by Chris Gunn):
22. Work on the telescope in November 2016. (Photo by Chris Gunn):
23. NASA completed assembly and testing of the James Webb Space Telescope in 2016. This is a snapshot from March 5, 2017. On long exposure, the techniques look like ghosts. (Photo by Chris Gunn):
26. The door to the very chamber A from the 14th photo, in which outer space is modeled. (Photo by Chris Gunn):
28. Current plans call for the telescope to be launched by an Ariane 5 rocket in spring 2019. Asked about what scientists expect to learn with the new telescope, project lead researcher John Mather said, "I hope we find something that no one knows anything about." (Photo by Chris Gunn):
James Webb is a very complex system with thousands of individual elements. They form the telescope mirror and its scientific instruments. As for the latter, these are such devices:
Near-Infrared Camera;
- The device for work in the middle infrared range (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 shield that will shield it from the Sun. The fact is that it is thanks to this screen that James Webb will be able to detect even the very faint light of the most distant stars. To unfold the screen, a complex system of 180 different devices and other elements has been created. Its dimensions are 14 * 21 meters. "It makes us nervous," admitted the head of the telescope project.
The main tasks of the telescope, which will replace the Hubble in the ranks, are: detection of light from the first stars and galaxies formed after the Big Bang, study of the formation and development of galaxies, stars, planetary systems and the origin of life. Also, "Webb" will be able to tell about when and where the reionization of the Universe began and what caused it.
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