telescope

[wàng yuǎn jìng]

optical instrument

open 7 entries with the same name

Collection

zero Useful+1

zero

A telescope is a kind of telescope that uses a lens or reflector And other optical devices optics Instrument. It uses the Ray refraction Or light is Concave mirror The reflection makes it enter into the small hole and converge to form an image, which is then magnified eyepiece When seen, it is also called the "thousand mile mirror".

The first function of the telescope is to enlarge the angle of distant objects so that the human eye can see clearly Angular distance Smaller details. The second function of the telescope is to objective lense The collected light beam which is much thicker than the pupil diameter (maximum 8 mm) is sent to the human eye to make Observer It can see dim objects that can't be seen before.

In 1608, Netherlands Hans Lieberthi, an optician of, accidentally found that you can see distant scenery with two lenses. Inspired by this, he built the first telescope in human history. 1609 Italy Florence people Galileo Galilei He invented the 40x double mirror telescope, which is the first practical telescope put into scientific application. After more than 400 years of development, the telescope has become more and more powerful, and the observation distance is also getting farther and farther.

Chinese name: telescope
Foreign name: telescope
Alias: field glasses

Principle: Lens or reflector
inventor: Netherlands Man Hans Lieber
Invention time: 1608
product type: optical instrument

catalog

development history

Announce

edit

Hans Lippershey

1608 Netherlands Middleburg Optician Hans Lipol Hans Lippershey built the world's first telescope. once, Two children Playing with some lenses in front of Lipol's shop, they looked at the weathercock on the church in the distance through the front and back lenses, and they were very happy. Liposser picked up two lenses and saw that the weathercock in the distance magnified a lot. Lippol raced back to the store and put two lenses in one Bobbin After many experiments, Hans Lipper invented the telescope. The telescope he made for himself in 1608 Patent application And complied with the requirements of the authorities to build a Binoculars 。 It is said that dozens of telescope opticians in the town claimed to have invented the telescope.

At the same time, the German astronomer Kepler also began to study telescopes, and he proposed another kind of Astronomical telescope This telescope is composed of two convex lenses, which is different from Galileo's telescope Galileo telescope Wide field of vision. But Kepler did not manufacture the telescope he introduced. Shaina made this telescope for the first time between 1613 and 1617. He also made a telescope with a third convex lens according to Kepler's suggestion Convex lens The inverted image of the telescope becomes Positive image 。 Shaina has made eight telescopes, one by one, to observe the sun. No matter which one can see the same shape Sunspot 。 Therefore, he dispelled many people's illusion that sunspots may be caused by dust on the lens, and proved that sunspots really exist as observed. Observing Solar time Shaina puts on special Blackout glass Galileo did not add this Protector As a result, he hurt his eyes and almost lost his sight. Huygens in the Netherlands Refracting telescope In 1665, a telescope with a tube length of nearly 6 meters was built to explore Saturn And later made another one that was nearly 41 Meter long A telescope.

William Herschel

In 1793, William Herschel of England made Reflecting telescope ， reflector 130 cm in diameter Copper tin alloy Made of, weighing up to 1 ton.

It was made by William Parsons of England in 1845 Reflecting telescope The diameter of the reflector is 1.82m.

In 1917, Hooke The Hooker Telescope in the United States California Of Mount Wilson Observatory Completed. its primary mirror The caliber is 100 inches. It was with this telescope that Edwin Hubble discovered the amazing fact that the universe is expanding.

Hooker Telescope

In 1930, German Bernhard Schmidt Refracting telescope and Reflecting telescope Advantages of (refracting telescope aberration Small but with chromatic aberration, and the larger the size, the more expensive it is. The reflecting telescope has no chromatic aberration, is cheap, and the reflector can be made very large, but with aberration.) Catadioptric telescope 。

After the war, the reflecting telescope Astronomical observation In 1950, a Hale reflecting telescope with a diameter of 5.08 meters was installed on Palomar Mountain.

1969, before Soviet Union A reflector with a diameter of 6 meters was installed on the Pastuhov Mountain in the north of the Caucasus.

Chile VLT Telescope^[1]

In 1990, NASA Will Hubble Space telescope However, due to mirror failure, it was not until 1993 when astronauts completed space repair and replaced the lens, hubble space telescope Only then began to play a full role. Because you can not Earth's atmosphere Of the Hubble Space Telescope Image definition It is 10 times the image taken by similar telescopes on the earth.

In 1993, the United States was in Hawaii Mauna Kea A 10 meter caliber“ Keck telescope ”The mirror surface is composed of 36 pieces of 1.8m reflectors.

In 2001, located in Chile Of European Southern Observatory Development completed“ Very large telescope ”(VLT), which consists of four 8-meter telescopes Light gathering ability It is equivalent to a 16 meter reflecting telescope.

European Extra Large Telescope (E-ELT)^[1]

On June 18, 2014, Chile will level the top of Cerro Amazons to house the most powerful telescope in the world“ European Astronomical Telescope ”(E-ELT). The Sailo Amazon is located in Atacama Desert, with an altitude of 3000 meters.

E-ELT, also known as "the world's largest eye of the sky", is nearly 40 meters wide and weighs about 2500 tons Luminance ratio Existing telescopes are 15 times higher, definition It's 16 times the size of the Hubble telescope. The telescope costs 879 million pounds (about RMB 9.3 billion yuan), which is expected to be officially put into use in 2022.

A group of telescopes under construction began to impact the white giant brothers on the Monakia Mountain again. These new competitors include "30m" Large telescope ”(Third Meter Telescope, TMT for short), 20 meter diameter Large Magellan Telescope (Giant Magellan Telescope (GMT) and the Overwhelming Large Telescope (OWL) with a diameter of 100 meters. Their advocates point out that these new telescopes can not only provide images with better quality than those of the Hubble telescope Space pictures And can collect more light Galaxy formation We can learn more about the initial stars and cosmic gas, and see the planets around distant stars clearly.

At the beginning of November 2021, James Webb Space Telescope Arrived at French Guyana Of Launch site , which will be launched in December.^[2]

Fundamentals

Announce

edit

telescope

The telescope is a visual optical instrument used to observe distant objects. It can magnify the small angle of the distant object at a certain magnification, so that it has a large angle in the image space, making objects that could not be seen or distinguished with the naked eye become clear and recognizable. Therefore, telescopes are astronomical and Ground observation An indispensable tool in. It is a kind of objective lense and eyepiece Incident Parallel beam Still shooting in parallel optical system 。 According to the principle of telescope, there are generally three types. One is through collection electromagnetic wave The instrument used to observe the electromagnetic radiation of distant objects is called radio telescope In daily life, telescope mainly refers to Optical telescope But in modern astronomy, Astronomical telescope Including radio telescope Infrared telescope 、 X-ray and Gamma ray telescope. The concept of astronomical telescope is further extended to Gravitational wave 、 cosmic rays and dark substance The domain of.

The optical telescope in daily life is also known as the "telescope". It mainly includes amateur astronomical telescopes, drama viewing telescopes and military binoculars.

frequently-used Binoculars In order to reduce the volume and reverse the inverted image, it is necessary to add Prism System Prism system can be divided into Roof Prism (that is, Schmidt Behan roof prism system) and Porro prism The principle and application of the two systems are similar.

personal use The small hand-held telescope should not be used with too large magnification. Generally, it is better to use 3~12 times. When the magnification is too large, imaging definition Will Variogram At the same time, the jitter is serious, and more than 12 times of the telescope is generally used lampstand And so on.

type

Announce

edit

Refracting telescope

Galileo's refracting telescope

Refracting telescope A telescope that uses a lens as its objective lens. There are two types: Concave lens do eyepiece Scale of Galileo telescope ； from Convex lens Weigh for eyepiece Kepler telescope 。

Galileo telescope

objective lense yes Convergent lens And the eyepiece is divergent lens A telescope. The light is refracted by the objective lens Real image At the focus behind the eyepiece (close to the rear of the human eye), this Like pair The eyepiece is a Virtual image Therefore, it is refracted into a magnified upright virtual image. Galilean Magnification It is equal to the ratio of objective focal length to eyepiece focal length. Its advantage is that the lens tube is short and can form a positive image, but its field of vision is relatively small. Put two Magnification The low Galileo telescopes are arranged side by side, and a bolt button is used in the middle to adjust their clarity at the same time, which is called“ Opera spectator ”； Because it is convenient to carry, it is often used to watch performances. Galileo's telescope plays an important role in the history of human understanding of nature. It consists of a concave lens (eyepiece) and a convex lens (objective lens). Its advantages are simple structure and direct image formation.

Structure diagram of telescope

Kepler telescope

Kepler telescope The basic principle is that the distant light first enters the convex lens of the objective lens, and becomes inverted and reduced for the first time Real image , equivalent to a camera; Then the real image enters eyepiece The convex lens of is upright and magnified for the second time Virtual image , which is equivalent to magnifier 。

because Single lens Sum of objective chromatic aberration Spherical aberration Both are quite serious, modern Refracting telescope Two or more lenses are commonly used as crop mirrors. Among them Double lens objective (Normal Achromatic telescope ）The most common application. It consists of Crown Glass Made convex lens and a piece of Flint glass Made of concave lens, completely eliminates two specific wavelengths Positional chromatic aberration The chromatic aberration of other wavelength positions can also be reduced accordingly.

When certain design conditions are met, some can be eliminated Spherical aberration and Coma 。 Due to the influence of residual chromatic aberration and other aberrations relative aperture Smaller, generally 1/15-1/20, rarely greater than 1/7, available field Not much. The double lens objective with aperture less than 8 cm can transfer two lenses Gluing Together, they are called double glued objectives, and those with a certain gap but not glued are called double separated objectives. In order to increase the relative aperture and field of view, multi lens objective lens sets can be used. For Galileo telescope, its structure is very simple and light energy loss is small. The lens tube is short and light. And become Positive image , but multiple small field of view is narrow, generally used for Opera spectator and Toy telescope 。 For Kepler telescope, it is necessary to add prism group or lens group behind the objective lens to rotate the image, so that the eye can observe the positive image. The Kepler structure is commonly used in refractive telescopes. Because the imaging quality of the refracting telescope is better than Reflecting telescope Good, large field of view, easy to use, easy to maintain, medium and small Astronomical telescope And many special instruments Refracting system However, it is much more difficult to manufacture a large refracting telescope than a reflecting telescope, because it is very difficult to smelt high-quality lenses with large aperture, and Glass pair The absorption of light, and Primary mirror The lens will be deformed due to gravity, resulting in poor optical quality, so large aperture telescopes are reflective

Schematic diagram of optical principle of Kepler telescope

Kepler telescope consists of two convex lenses. Because there is a Real image , easy to install Reticle , and various performances are excellent, so Military telescope , Small Astronomical telescope Such professional telescopes all use this structure. But this kind of structural imaging is upside down, so it is necessary to add Positive image system 。 Positive image system can be divided into two types: prism positive image system and lens positive image system. Our common model of wide front and narrow back Binoculars The double right angle telescope positive image system is adopted. The advantage of this kind of system is that it can make optic axis The telescope is folded twice, thus greatly reducing the size and weight of the telescope. The lens positive image system uses a group of complex lenses to reverse the image, which is expensive, but Russia 20 × 50 three section telescopic classical type Monocular telescope Both well-designed lens positive image system is adopted.

Schematic diagram of optical principle of Kepler telescope

History of Kepler Telescope

In 1611, the German astronomer Kepler used two pieces of Biconvex lens As objective lens and eyepiece respectively, the magnification has been significantly improved optical system be called Kepler telescope 。 The refracting telescopes used by people are still in these two forms, and the astronomical telescopes are generally Kepler type.

It should be pointed out that, since the telescope at that time used a single lens as the objective lens, there was serious chromatic aberration curvature Very small lens, which will inevitably lead to the lengthening of the mirror body. So for a long time, astronomers have been dreaming of making longer telescopes, and many attempts have failed.

In 1757, Dulong By studying the refraction and dispersion , established Achromatic lens The achromatic lens is made of Mian brand glass and flint glass. Since then, the achromatic refracting telescope has completely replaced the long body telescope. However, due to technical limitations, it is difficult to cast large flint glass. In the early days of achromatic telescopes, only 10 cm lenses can be ground at most.

The effect of the lens on the Radiation absorption Very severe. And huge optical glass Casting was also very difficult. By 1897, the Keshi 1-meter telescope had been built, and the development of refracting telescopes had reached its peak. In the following 100 years, no larger refracting telescope had appeared. This is mainly because it is technically impossible to cast a large piece of perfect glass as a lens, and because gravity makes the deformation of large lenses very obvious, thus losing sharp focus.

Reflecting telescope

Is concave reflector A telescope for crop mirrors. Can be divided into Newton telescope ， Cassegrain telescope And so on. But in order to reduce other aberration The available field of view is small. Only the material for manufacturing the reflector is required Coefficient of expansion Small, low stress and easy to grind. The polished mirror is usually coated with an aluminum film, which is in the range of 2000-9000 angstrom reflectivity Are more than 80%, so in addition to the optical band, the reflecting telescope is also suitable for Near infrared And near ultraviolet band. The relative aperture of the reflecting telescope can be larger. The relative aperture of the main focus reflecting telescope is about 1/5-1/2.5, or even larger Newton telescope In addition, the length of the lens barrel is much shorter than the focal length of the system. In addition, the main mirror has only one surface to be processed, which greatly reduces the cost and manufacturing difficulties. Therefore, the diameter of the Optical telescope All are reflecting telescopes. A large aperture reflecting telescope Secondary mirror , available Main focus system (or Newton system), Cassegrain system and folding axis system. In this way, a telescope can obtain several different relative apertures and fields of view. The reflecting telescope is mainly used for Astrophysics Work on.

Imaging principle of reflecting telescope

Reflecting telescope history

First Reflecting telescope Born in 1668, Newton decided to adopt Spherical reflector As the primary mirror. He uses 2.5 cm diameter metal to grind a concave reflector, so that the convergent light reflected by the main mirror can reach the target after being reflected out of the mirror cylinder at an angle of 90 ° by the reflector eyepiece 。 This system is called Newton reflecting telescope 。 its Spherical mirror Although it will produce certain Aberration However, it is a great success to replace the refractor with a reflector.

James Gregory In 1663, a scheme was put forward: use one primary mirror and one secondary mirror, both of which are Concave mirror The secondary mirror is placed outside the focus of the primary mirror, and a small hole is left in the center of the primary mirror, so that the light can be emitted from the small hole after being reflected twice by the primary mirror and the secondary mirror and reach the eyepiece. The purpose of this design is to eliminate spherical aberration and chromatic aberration at the same time, which requires a paraboloid And one Ellipsoid This is theoretically correct, but the manufacturing level at that time could not meet this requirement, so Gregory He can't get a mirror that is useful to him.

In 1672, French Cassegrain proposed the third type of reflecting telescope design scheme The structure is similar to that of the Gregory telescope, but the difference is that the secondary mirror is advanced to the focus of the primary mirror and convex mirror This is the most commonly used Cassegrain reflection telescope. This makes the light reflected by the secondary mirror slightly divergent, reducing the magnification, but it eliminates spherical aberration, so that the telescope can also make the focal length very short.

Cassegrain telescope The primary mirror and secondary mirror can have many different forms, and the optical performance is also different. The Cassegrain telescope has a long focal length and a short body, Magnification Also large, the image obtained is clear; It has Cassegrain focus, which can be used to study celestial bodies in small field of view, and can be configured Newton focus , used to photograph large areas of celestial bodies. Therefore, Cassegrain telescope has been widely used.

At the end of 1918, the diameter of 254cm Hooke telescope It was put into use and was built under the leadership of Haier. astronomer It is the first time that this telescope has revealed Galaxy The true size of the Cosmic expansion theory It is the result of observation with Hooke telescope.

In the 1920s and 1930s, the success of the Hooke Telescope inspired astronomers to build larger reflective telescopes. In 1948, the United States built a telescope with a diameter of 508cm. In memory of Haier, the telescope maker, it was named Haier telescope 。 It has been more than 20 years since Haier Telescope was designed and manufactured. Although it can see farther than Hooke Telescope, Resolution Stronger, but it does not make human beings have a new understanding of the universe. As Asimov said, "Haier Telescope (1948) is just like the Yerkes telescope (1897), which seems to indicate that a certain type of telescope is about to develop to its end. " Before 1976 Soviet Union A 600cm telescope has been built, but its role is not as good as that of Haier telescope, which also confirms what Asimov said.

Reflective telescopes have many advantages, such as no chromatic aberration visible light It records the information sent by the celestial body within the range, and is easier to make than the refracting telescope. However, due to its inherent shortcomings, such as the larger the aperture, the smaller the field of view, and the objective lens needs to be coated regularly.

Catadioptric telescope

On the basis of spherical mirror, the refractive element for aberration correction is added, which can avoid difficult large-scale aspheric surface processing and obtain good image quality. The more famous ones are Schmidt telescope 。

It is located in the Spherical center Place a Schmidt correction plate at position. One face is flat, and the other is slightly deformed aspheric surface , so that the central part of the beam slightly converges and the peripheral part slightly diverges, just correcting spherical aberration and coma. There is another Maksutov telescope 。

Add a crescent lens in front of the spherical mirror, and select the appropriate Meniscus lens The spherical aberration and coma can be corrected at the same time. And derivatives of these two telescopes, such as Super Schmidt telescope , Beck Nuen camera, etc. stay Catadioptric telescope In, the image is formed by the reflector, and the refractor is used to correct the aberration. It is characterized by large relative aperture (even greater than 1), strong light power, wide field of view and excellent image quality. Suitable for sky survey photography and observation of nebulae comet , meteors and other celestial bodies. If catadioptric Cassegrain system is adopted for small visual telescope, the lens tube can be very short.

Catadioptric telescope history

Catadioptric telescope It first appeared in 1814. In 1931, German optician Schmidt used a unique aspherical surface close to a parallel plate Thin lens As Corrector , which can eliminate spherical aberration and Off-axis aberration Schmidt catadioptric telescope, which has strong light power field Large Aberration Small, suitable for taking pictures of large areas of the sky, especially for weak nebulae. Schmidt telescope has become Astronomical observation Important tools.

In 1940, Marksutov used a crescent shaped lens as the correction lens to manufacture another type of catadioptric telescope. Its two surfaces are two spheres with different curvature, which are not different, but the curvature and thickness are both large. All its surfaces are spherical Schmidt telescope The correction plate is easy to grind, and the lens tube is relatively short, but the field of view is smaller than that of Schmidt telescope, and the requirements for glass are higher.

Since the catadioptric telescope can take into account the advantages of both refraction and reflection telescopes, it is very suitable for amateur astronomical observation and Astronomical photography , and got a lot of Astronomer Love.

Maksutov telescope

A catadioptric telescope Soviet Union optics It was invented by Mark Sutov, hence the name. Netherlands The optician Bauworths also independently invented similar systems almost at the same time, so it is sometimes called the Marksutov Bauworths system.

The optical system of the Maksutov telescope is similar to that of the Schmidt telescope. It is composed of a concave spherical mirror and a lens added in front to correct spherical aberration. The correction lens is spherical, and its two surfaces are Radius of curvature The difference is small, but there is considerable curvature and thickness, and the lens is Lunate Therefore, this system is sometimes called the meniscus system. Proper selection of the curvature radius and thickness on both sides of the lens can make the meniscus lens produce enough compensation Concave spherical mirror At the same time, it meets the achromatic condition. The coma can be corrected by properly adjusting the distance between the meniscus lens and the spherical mirror in the whole system: Astigmatism Very small, but Field music It is relatively large, so the curved negative corresponding to the focal plane must be used. The central part of the second side of the meniscus lens can be ground into a sphere with a longer radius of curvature (or it can be a glued lens) to form a Maksutov Kaseglin system with the required relative aperture, or the central part of the meniscus lens can be directly aluminized to form a Maksutov Kaseglin system. The main advantages of the Maksutov telescope are that all surfaces in the system are spherical and easy to manufacture; With the same aperture and focal length, the length of the lens tube is shorter than that of Schmidt telescope. Disadvantages: Compared with the same Schmidt telescope, the field of view is slightly smaller; Meniscus lens The thickness of is relatively large, generally about 1/10 of the aperture. There is a high requirement for the optical glass to be used, so the increase of the aperture is limited.

The largest Maksutov telescope is located in Abbas Tumani, the Soviet Union observatory The diameter of the meniscus lens is 70cm, the diameter of the spherical mirror is 98cm, and the focal length is 210cm.

radio telescope

Detecting celestial bodies Radio radiation Basic equipment of. It can measure the intensity, spectrum and polarization of celestial radio. Typically, by antenna 、 Receiver and terminal equipment 3 parts. The antenna collects radio radiation from celestial bodies, and the receiver processes and converts these signals into a form that can be recorded and displayed. The terminal equipment records the signals, performs some processing according to specific requirements, and then displays them. Characterizing the performance of radio telescope Basic indicators yes spatial resolution And sensitivity, the former reflects the difference between two celestial sphere Radio close to each other on point source The latter reflects the ability to detect weak radio sources. Radio telescope usually requires high spatial resolution and high sensitivity. According to antenna overall structure Radio telescopes can be divided into Continuous aperture And discontinuous aperture. The former is mainly represented by the classical type of single disk parabolic antenna radio telescope The latter is a variety of combined antenna systems based on interference technology. In the 1960s, two new types of discontinuous aperture radio telescopes were produced—— Very long baseline interferometer and Synthetic aperture radio telescope The former has very high spatial resolution, while the latter can obtain clear radio images. The world's largest traceable classical radio telescope, with a parabolic antenna up to 100 meters in diameter, is installed at the Max Planck Institute of Radio Astronomy in Germany; The largest discontinuous aperture radio telescope in the world is the very large antenna array, which is installed on the National Radio Observatory 。

In 1931, in the United States New Jersey Of Bell Laboratories In charge of special search and identification of telephone interference signal American KG Jansky found that there is a kind of Maximum Of radio interference 。 After careful analysis, his article published in 1932 interrupted that this was radio radiation from the Milky Way. As a result, Jansky pioneered the use of Radio wave Astrological new era 。 At that time, he used a 30.5m long and 3.66m high rotation antenna array A 30 degree wide "fan-shaped" beam was obtained at 14.6 m wavelength. Since then, the history of radio telescopes has been the history of continuously improving resolution and sensitivity.

Space telescope

stay Earth's atmosphere Extraastronomic Large telescope 。 Since it avoids the influence of atmosphere and will not be distorted by gravity, it can greatly improve the observation ability and Discriminative ability And even some optical telescopes can be used as near-infrared Near ultraviolet Observation. But there are also many new strict requirements in manufacturing, such as mirror Machining accuracy To be within 0.01 microns, each component and Mechanical structure Be able to bear At launch It is vibrating and overweight, but it is required to be as light as possible to reduce the launch cost. First Space telescope also called hubble space telescope , dated April 24, 1990, by the United States Space Shuttle Discovery Put it on the track 600 kilometers above the ground. It is cylindrical in shape, 13 meters long and 4 meters in diameter. The front end is a telescope, second half It's an auxiliary device, Total weight About 11 tons. The telescope's Effective aperture It is 2.4 meters long, with a focal length of 57.6 meters. The observation wavelength ranges from 120 nm in the ultraviolet to 1200 nm in the infrared, with a cost of 1.5 billion dollars. The resolution of the original design is 0.005, 100 times that of the large ground-based telescope. However, due to a minor oversight in manufacturing, it was found that the instrument had a large spherical aberration until the sky, which seriously affected the quality of observation. December 2-13, 1993, USA Space Shuttle Endeavour Carrying 7 astronauts, we successfully replaced 11 parts for Hubble, completed the repair work, and created a large-scale repair project for human beings in space spacecraft History of. The successfully repaired Hubble telescope will continue to provide information about the depths of the universe within 10 years. In April 1991, the United States launched the second space telescope, which is an observation Gamma ray Device with total weight of 17 tons, power consumption of 1.52 watts, signal Transmission rate It is 17000 bits/second and contains four sets of detectors, Angular resolution 5 ′ - 10 ′. Its service life is about 2 years.

Gemini telescope

Gemini telescope It is an international equipment dominated by the United States (of which, the United States accounts for 50%, the United Kingdom accounts for 25%, Canada 15%, Chile 5%, Argentina 2.5%, Brazil 2.5%), which is implemented by the American University Astronomical Telescope Alliance (AURA). It consists of two 8m telescope Composition, one on Northern Hemisphere One is placed in the southern hemisphere for systematic observation throughout the day. Its main mirror adopts Active optics Control, the secondary mirror makes rapid correction of tilt mirror, and will also pass Adaptive optics system Make the infrared area close to Diffraction limit 。

Solar telescope

Corona It is a thin and weak outer atmosphere around the sun. Its structure is complex Total solar eclipse It can only be appreciated in a short time, because the light in the sky is always scattered or diffused into the telescope from all directions.

The first one was developed by French astronomer Leo in 1930 Coronagraph This instrument can effectively block out the sun, Scattered light Extremely small, so it can be used in sunlight In any day of Puzhao, successfully took photos of the corona. Since then, the world has gradually observed the corona.

The coronagraph is just Solar telescope Since the 20th century, due to the needs of practical observation, various solar telescopes have emerged, such as Chromosphere telescope 、 Solar tower 、 Combined solar telescope and Vacuum solar telescope Etc.

Infrared telescope

Infrared telescope (infrared telescope) infrared radiation A telescope. The shape structure is similar to that of optical mirror, and some can be used for infrared observation and Optical observation 。 However, the terminal equipment for infrared observation is quite different from that for optical observation modulation technique To suppress Background interference And use interferometry to improve its resolution. Infrared observation imaging is also related to optical image be quite different. Because the earth's atmosphere infrared There are only seven narrow "windows", so infrared telescopes are often located in high mountain areas. Most of the world's better ground-based infrared telescopes are installed in Hawaii, USA Monakia is the research center of infrared astronomy in the world. Built in 1991 Keck telescope It is the largest infrared telescope with an aperture of 10 meters, and can be used for both optical and infrared purposes. In addition, the infrared telescope can be mounted on the High-altitude balloon The infrared telescope on the balloon Maximum diameter It is 1 meter, but the effect is comparable to some infrared telescopes with larger aperture on the ground.

Digital telescope

Be mainstream Science and technology media Rated as one hundred technological innovation ”First, because of its simple structure and clear imaging, it can achieve the effect of ultra long focus with a small body length. In addition to advanced digital functions, it can achieve clearer photography and video recording functions, which greatly broadens the scope of the telescope application area Can be widely used in investigation birdwatching , electricity Wildlife protection wait.

Digital telescope With the photo function, you can save many unforgettable moments in your life. In the United States, this product is widely used by sports coaches Scouting , bird hunter wild animal observer , hunting enthusiasts and any photography and video enthusiasts. In China, the leader in this field is the watchto series remote shooting equipment, especially the WT-20A series and 30B series. Many domestic public security, military police and wildlife protection have taken advantage of digital telescopes and applied them to their work, especially the public security departments, who can easily take remote photos and obtain evidence.

Up to 5.1 megapixel cmos sensor integrated digital camera. It can quickly and simply switch from static high-resolution photos (2594 * 1786) to 30 second continuous photography. This ensures that you capture the best results. Photos and videos are stored in memory, or SD card Medium, and can be accessed via the collapsible LCD View, delete, view via TV, or without installing other software Photo download To your computer. Main popular optical parts Multiplication It is 35 times and 60 times, and can switch high and low times（ Windows 2000 , XP or Mac No drive required, Windows 98 /The 98SE requires a drive to be installed.)

Hard X-ray modulation telescope

In 2015, as an important research tool in the field of space astronomy Satellite launch A breakthrough of zero will be achieved. from Academician of CAS , China's famous high-energy celestial bodies physical scientist Li Shibei A new type of astronomical telescope—— Hard X-ray modulation telescope (HXMT) will be officially launched, becoming the first one in China Astronomical satellite 。

"According to the plan, all construction of HXMT will be completed in 2014, and it will be delivered in 2015 Low Earth orbit 。” Institute of High Energy Physics, Chinese Academy of Sciences Researcher, HXMT satellite Chief scientist assistant Zhang Shuangnan Accepted on《 China Science Daily 》The reporter said, "Astronomical satellites are generally divided into radio, ultraviolet, gamma ray and X-ray astronomical satellite 。 Hard under construction X-ray Modulation telescope (HXMT) belongs to X-ray astronomical satellite. In the history of space astronomy, it was also the first breakthrough in the field of X-ray. "

"In terms of function, astronomical satellites can be divided into special and observatory level ones. Special astronomical telescopes are designed and built for specific scientific research goals, while observatory level astronomical telescopes carry more instruments, which are more powerful and can involve scientific research The scope is also wider. HXMT is a special astronomical satellite, which is smaller than the observatory level. Compared with other special astronomical satellites, HXMT is a medium-sized special astronomical satellite. Last day, it will mainly undertake the research on black holes, as well as those related to black holes, such as neutron star "

In the universe, there are many extreme celestial bodies, such as black holes, and some extreme physical process It is impossible to conduct tests and observations on the ground. Therefore, astronomical satellite has become one of the most important research means.

With astronomical satellites countries and regions It can be divided into three echelons. The first echelon is dominated by the United States, and the second echelon includes European Space Agency , some countries in Europe, as well as Japan, Russia, China, Brazil, India, South Korea and Taiwan The region belongs to the third echelon. Among them, India is the most technologically advanced in the third echelon. It is expected to launch their astronomical satellites within one to two years, while Brazil is also planning to launch them in 2014.

Common parameters

Announce

edit

Magnification

General eyepiece visual angle and objective lens Angle of incidence As a telescope Magnification It is usually calculated by the ratio of objective focal length to eyepiece focal length to indicate the magnification of telescope angle of view. For example, a telescope with a magnification of 10 means that the target with a 1 degree angle of view can be magnified to 10 degrees.

Field angle

（ field Range) is marked with the product visual scene range at 1000m, such as 126m/1000m, indicating the distance Observer 1000 meters away, the telescope can observe the field of view within 126 meters.

Exit pupil diameter

telescope

Is a parameter that roughly describes the brightness of the image. In weak Light environment Lower, larger Exit pupil diameter , which can bring clearer images. The human pupil, under normal physiological conditions, cannot exceed 7mm at most, so the exit pupil diameter greater than 7mm is unintentionally a waste of light. This parameter cannot fully reflect the quality of the telescope, because this parameter can meet the numerical requirements as long as it meets the manufacturing specifications. The larger the diameter of the exit pupil is, the more suitable it is for use in a bumpy environment, and the observation picture will be more stable. Therefore, telescopes such as the 7X50 are mostly suitable for use at sea. This value can be divided by the objective diameter Magnification obtain.

resolving power

Resolution, Hong Kong and Taiwan It is called interpretive degree) Precision , refers to the number of pixels that the display can display. Since the dots, lines and planes on the screen are all composed of pixels, the more pixels the display can display, the finer the picture will be, and the more information can be displayed in the same screen area, so the resolution is very important performance index one of.

Twilight coefficient

Published by Zeiss Optics, Germany. It reflects the observation efficiency of telescopes with different apertures and magnification under dark light conditions. Calculation method: square root of the product of telescope magnification and aperture.

Effective diameter and relative diameter

The distance from the center of the objective lens to the focus is called the focal length of the objective lens, which is represented by the symbol F. The diameter of the objective lens is not framed and Diaphragm The blocked part is called objective lens Effective aperture , denoted by the symbol D. The performance of astronomical telescope is mainly marked by these two data.

Collecting power

In dark places, the pupil diameter of the human eye is generally about 7 mm. Therefore, the objective of the telescope Effective area The multiple relative to the pupil area is called Collecting power 。 Namely: light gathering force=(D * D)/(7 * 7), where D is in mm.

English abbreviation

Announce

edit

English letter Model of

The model of English letters sometimes has different meanings in different telescope manufacturers. Generally, it is easy to identify the following:

(1) CF: central focus

(2) ZCF: traditional Baltic prism left and right expansion, central focusing

(3) ZWCF: one more than item (2)“ Super wide-angle ”（W）

(4) CR : camouflage rubber Housing

(5) BR: Black rubber shock proof housing

(6) BCF: black, central focus

(7) BCR: black camouflage rubber shell

(8) IR： aluminium alloy Lightweight housing

(9) IF: Individual focusing of left and right eyes

(10) WP : nitrogen filled Waterproof type

(11) RA: rubber shock protection

(12) D: German prism roof prism (straight cylinder type)

(13) HP : High focus

(14) SP: superelevation Resolution

(15) ED: Ultra low chromatic aberration lens

(16) AS： Aspherical lens

(17) ZOOM: variable magnification Telescopic lens

(18) WF: Wide angle view

Optional maintenance

Announce

edit

maintain

telescope

1. Ensure that the telescope is stored in a ventilated, dry and clean place to prevent mildew. If possible, it can be placed around the telescope desiccant , and replace it frequently.

2. The residual dirty spots or stains on the lens should be gently wiped with a professional lens wiping cloth to avoid scratching the mirror surface. If the mirror surface needs to be cleaned, it should be cleaned with Absorbent cotton Take a little alcohol, wipe from the center of the mirror to the edge of the mirror in one direction, and constantly replace the absorbent cotton ball until it is clean.

3. The telescope is a precision instrument. Do not throw, press or do other violent actions on the telescope.

4. Non professionals should not attempt to disassemble the telescope and clean its interior.

5. Do not collide with sharp objects, such as Nails , needle, etc.

6. Pay attention to moisture-proof and waterproof when using the telescope. As a precision instrument, telescope should not be used in harsh conditions.

choose

1. Optical quality and lightweight appearance are often contradictory. If you want both, you need to significantly increase the budget.

2. Each type and specification of telescope has a specific environment suitable for its use to achieve perfect results. No telescope is omnipotent.

3. Roof prism telescope has the smallest volume among the telescopes of the same specification, but its optical quality is often not as good as that of poro prism telescope.

4. The price of the telescope depends on many external factors, such as cost, profit Market strategy It has nothing to do with the multiple of telescope.

5. The imaging effect of a telescope depends on many factors, and the multiple is only one of them. It is not advisable to blindly pursue the multiple.

6. The possibility of fake military telescopes is very high. Regular military telescopes are basically black and expensive.

7. Do not buy binoculars with large range magnification. There are many problems, such as small field of view, serious imaging distortion, and easy optical axis deviation.

8. You need to know that every price is worth every product. The actual effect of telescopes with the same specifications and parameters may be very different, and the price will also vary by thousands of miles.

9. Try not to buy a red film telescope. It is only suitable for Snow and ice Contour reflective environment, General environment The image under is dim, and Color cast Serious.

10. There's never any infrared Night vision telescope However, some telescopes, such as the 7X50, also work well in low light environment.

11. The telescope selection should refer to third-party websites and evaluation experience articles as much as possible to maximize the advantages, disadvantages and characteristics of the telescope.

Coating

The direct light will destroy the image presented in the telescope. In order to enhance visual image, lenses and prisms need to be coated Polarization Membrane. Generally, the single layer of the visual telescope Antireflective film The design has the best antireflection effect for the yellow green light with a wavelength of 5500A, because the human eye is most sensitive to the light in this wave band. Therefore, it reflects more blue and red light. plating Multilayers The lenses of Dark purple , such as Camera lens Coating. A single film that is too thick will appear green.

There will be a mark of lens coating on the binocular mirror, indicating the optical quality of the binocular mirror. The types of coating are as follows:

Coated Optics (Coating): It is the lowest level antireflection film. It only means that at least one optical surface is coated with a single-layer antireflection coating, which is usually applied to two objectives and eyepieces Outer surface The inner lens and prism are not coated.

Fully Coated: All lenses and prisms are coated with a single layer of film, but if used in eyepiece Optical plastics The plastic lens may not be coated.

Multi Coated: at least one optical surface is coated with a multilayer antireflection coating, while other optical surfaces may be coated with a single layer or not at all; Usually, only two objective lenses and the outer surface of the eyepiece are coated with multilayer films.

Fully Multi Coated: All lenses and prisms are coated with antireflection coatings. Some manufacturers have coated multilayers on all optical surfaces, while others have only coated multilayers on some optical surfaces, and other surfaces are still coated with single layers.

Wideband green film, decorative green film, red film and blue membrane , and Purple membrane And yellow film, etc.:

Broadband green film: in some places, it is also called antireflection green film, which is one of the best coatings in China. Different color bands will appear when observed from different angles (this is the performance of multi-layer coatings), and the imaging is good definition High, Color restoration Not bad.

Red film: generally only used for red dots. This is more general and has no characteristics.

Blue film: It is the most widely used coating method in China. Compared with the broadband green film, it is slightly yellow and dark. The blue film also has several layers. Some have three layers, five are better, and only one is worse.

Decorative green film: This is very immoral. The color is similar to the antireflective green film, but the optical performance is Don't flatter The easier way to identify is that the decorative green film reflects a lot of light, while the broadband green film is very light.

In a word, good lenses and coatings look very light, overall Transmittance It can be about 85% - 90%. If coated lenses are also used for internal lenses, the overall light transmittance can reach about 93% (relatively rare in China). However, the domestic lenses that even use broadband green films have more or less false edges. In order to achieve higher light transmittance, internal lens coating is also used to improve the optical performance, making the overall light transmittance reach 93% - 95%. Generally, the way to identify a good mirror is very simple. The darker the lens, the lower the light transmittance, and the mirror will be better.

Military and civilian

Although the basic principles of military telescopes are no different from those of ordinary civilian telescopes Use environment There are many differences between the two observation objects. The shell of the military telescope is made of metal instead of plastic to ensure no cracking and deformation after long-term use.

In contrast, ordinary civilian telescopes are worse in terms of sealing and materials. Some are not only plastic shells, but also internal lenses Plastic manufacturing 。

First, their optical systems are different. Most military telescopes have reticles, and those used at night also have reticles lighting 。 Military telescopic Pupillary exit distance Larger to Observer Wearing antigas mask 。 To prevent hitting the head during shooting, some Sight The pupillary exit distance is as large as 70 or 80 mm, and you should also have a soft and hard eye mask and forehead protection.

Military telescopes must pass through before leaving the factory environmental test , generally including vibration test High temperature (+55 ℃) test, low temperature (- 45 ℃) test, rain or Water immersion test 、 Air tightness test 。 After these tests, Product performance Still can Guaranteed on Only those within the specified range can leave the factory. Some products have their own mirrors dryer Before leaving the factory, draw out air and inject dry air or nitrogen to effectively prevent the internal lens from mildewing in the future Fogging 。

Because of these differences, the design and manufacture of military telescopes will cost much more, so their prices are also higher than those of ordinary civilian telescopes.

The most famous telescope

Announce

edit

To celebrate“ International Year of Astronomy 2009 ”, UK《 New scientist 》Selected Human history The most famous telescope. Here are the 14 most famous telescopes:

1. Galileo refracting telescope

Galileo was the first to realize that telescopes could be used Astronomical research People. Although Galileo did not invent the telescope, he improved the previous design and gradually enhanced its amplification function. The story happened in August 1609. Galileo was demonstrating his telescope to the Venetian ruler at that time. Galileo built a telescope with a diameter of 4.2 cm and a length of about 1.2 meters. He used Planoconvex lens As objective lens and concave lens as eyepiece, this optical system is called Galilean telescope 。 Galileo pointed to the sky with this telescope and got a series of important discoveries. Astronomy entered the era of telescopes from then on. The advantage of a refracting telescope is its long focal length, Negative scale Large, insensitive to lens tube bending, most suitable for Astrometry Work on. However, it always has residual color difference, and at the same time, it has a strong absorption of ultraviolet and infrared radiation.

2. Newton reflecting telescope

Hubble Space Telescope

The principle of Newton's reflecting telescope is not to use a glass lens to refract or bend the light, but to use a curved mirror to reflect the light to a focus. This method is several times higher than using a lens to magnify an object. Newton decided to use spherical mirror as the main mirror after many times of grinding aspherical lens failed. He grinds a concave reflector with 2.5 cm diameter metal, and places a reflector with an angle of 45 ° with the main mirror in front of the focus of the main mirror, so that the concentrated light after being reflected by the main mirror's reflector can reach the eyepiece after being reflected out of the mirror tube at an angle of 90 °. The main advantage of the reflecting telescope is that there is no chromatic aberration paraboloid It can also eliminate the spherical aberration diagram that shows the Replica 。

3、 Herschel telescope

In the late 18th century, German musician and astronomer William Herschel began to manufacture large reflective telescopes. The largest telescope manufactured by Herschel has a mirror aperture of 1.2 meters. The telescope is very heavy and needs four people to operate it. Herschel is a master of making reflective telescopes. In his early years, he was a musician. Because he loved astronomy, he began to grind telescopes in 1773. In his life, he made hundreds of telescopes. Herschel's telescope is made by placing the objective lens obliquely in the tube, which makes Directional light After reflection, it converges on one side of the mirror tube. After the invention of the reflecting telescope, the reflecting material has always been an obstacle to its development: the bronze used for casting mirrors is easy to corrode and has to be polished regularly, which costs a lot of money and time Corrosion resistance Good metals are denser and more expensive than bronze.

4、 Yerkes refracting telescope

The Yerkes Refractive Telescope is located in the United States Wisconsin Yerkes Observatory, Main lens Built in 1895, it was the largest telescope in the world at that time. At the end of the 19th century, with the improvement of manufacturing technology, it became possible to manufacture large aperture refracting telescopes, and then there was a climax of manufacturing large aperture refracting telescopes. Seven of the world's eight existing refracting telescopes of more than 70cm were built between 1885 and 1897, of which the most Representativeness The Yerkes telescope with an aperture of 102 cm, built in 1897, and the Riker telescope with an aperture of 91 cm, built in 1886. However, the development of the refracting telescope was limited later, mainly because it was technically impossible to cast a large piece of perfect glass as a lens, and the deformation of the large lens would be very obvious due to gravity, thus losing the sharp focus.

5、 Mount Wilson 60 inch telescope

In 1908, the American astronomer George Ellery Hale built a 60 inch reflecting telescope, which was installed on Mount Wilson. It was the largest telescope in the world at that time, spectral analysis 、 parallax Measurement, nebula observation, photometry and other astronomical fields have become the world's leading equipment. Although the aperture of the Hooke Telescope exceeded it several years later, it was still one of the largest telescopes in the world in the following years. In 1992, an early adaptive optics Facilities, so that its resolution can range from 0.5-1.0 Angular second Increase to 0.07 seconds.

6. Hooke 100 inch telescope

Sponsored by wealthy businessman John Hooker, a 100 inch reflecting telescope was built at Mount Wilson Observatory in 1917. For the next 30 years, it has been the largest telescope in the world. In order to provide smooth operation, the telescope Hydraulic system Liquid Mercury 。 In 1919, Albert Michelson installed a special device for this telescope: Interferometer This is the first application of optical interference devices in astronomy. Michelson can use this instrument to accurately measure the size and distance of stars. Henry Norris Russell used data from the Hooke Telescope to develop his classification of stars. Edwin Hubble used the 100 inch telescope to complete his key calculations. He determined that many so-called "nebulae" are actually extragalactic Galaxy 。 In Milton- Hermason With the help of red shift It shows that the universe is expanding.

7. Haile 200 inch telescope

Hale was not very satisfied with the Hooker 100 inch telescope. In 1928, he decided to Palomar Observatory A giant reflecting telescope with an aperture of 200 inches was set up. The new telescope was completed and put into use in 1948. Haile graduated from the United States in 1890 Massachusetts Institute of Technology 。 In 1892 University of Chicago Astrophysics Associate professor, start organizing Yerkes Observatory , acting as the director. In 1904, Mount Wilson Sun was built observatory Later Mount Wilson Observatory. He served as the first director until he retired due to illness in 1923. In 1895, Hale founded the Journal of Astrophysics. In 1899, he was elected as the vice president of the newly established American Astronomical and Astrophysical Society. The most important contribution of Haile's life is reflected in two aspects: Observational research And making giant telescopes.

8、 Horn antenna

The horn antenna is located at the Bell Telephone Experimental Research Institute in New Jersey, USA, and was used to detect and discover cosmic microwave Background radiation 。 The horn antenna was built in 1959. When the horn length is fixed, if the horn angle gradually increases, the mouth size and the quadratic phase difference It also increases at the same time, but the gain does not increase synchronously with the mouth size, but there is a mouth size whose gain is the maximum. A speaker with such a size is called the best speaker. Horn antenna radiation field Available Huygens principle Calculated from the mouth field. The mouth field is determined by the mouth size of the horn and the propagation wave pattern. Available Geometry diffraction The influence of horn wall on radiation is calculated theoretically, so that the calculation Pattern And Measured value The anastomosis was good up to the distal side lobe.

9、 Very Large Array Radio Telescope

Very large array The radio telescope is located in the United States New Mexico Sokolo was built and put into use in 1980. The VLA consists of 27 surfaces with a diameter of 25 meters Parabolic antenna Composed in Y shape. Astronomers can use VLA to study various phenomena in the universe, such as black holes and nebulae. The VLT is an array of optical telescopes. It includes four 8.2 meter telescopes, each of which is a large telescope, and each of which can work independently, and has the ability to capture more than human beings Visual observation The incoming light is 4 billion times weaker than the South Africa The weakest light that a large telescope can capture is four times weaker. The VLA telescope can gather up to three telescopes together to form an independent unit, and combine the light into a unified beam through the underground lens, which makes Telescope system An image with a resolution 25 times higher than that of a single telescope can be observed.

10. Hubble Space Telescope

The Hubble Space Telescope was launched in April 1990. It is located in Earth's atmosphere So it gets all the other Ground-based telescope A revolutionary breakthrough that has never been achieved. Astronomers use it to measure the Expansion ratio And the expansion Dark energy And mysterious power. The Hubble Space Telescope has reached its old age. It has experienced several overhauls during its ten years in space. Although after each overhaul, "Hubble" takes on a new look, especially in 2001, scientists used Columbia Space Shuttle The fourth overhaul was carried out for it. The mapping camera was installed and replaced Solar panel , replace the power that has worked for 11 years control device And activate the near-infrared camera and multi-target in the "Sleep" state spectrometer However, the overhaul cannot cover up its old state, because Hubble has been in the state of "sticking to work with illness" since it went into space.

11. Keck series telescope

The Keck telescope is located in the Mauna Kea Mountains, Hawaii, with an aperture of 10 meters. Because today's technology can not achieve monolithic Telescope mirror The aperture is more than 8.4 meters, so the mirror surface of Keck telescope consists of 36 pieces hexagon It is composed of pieces. The huge mirror of the Kenet telescope makes it unusual to use, not only because of its large size, but also because it is composed of 36 small hexagonal lenses with a diameter of 1.8 meters. The Keck telescope ushered in a new era of ground-based telescopes. Its scale is twice that of the Haile telescope on Palomar Mountain in California, the United States, which was the largest telescope in the world in the past few decades. Some people once thought that it was impossible to make such a large telescope, but new science and technology turned the impossibility into reality.

12. Sloan 2.5 meter telescope

“ Sloan Digital Sky Survey Program ”The 2.5 meter telescope is located at the Cape Abbott Observatory in New Mexico, USA. The telescope has a rather complex digital camera 30 inside the telescope Charge coupled device （ CCD ）Detector. Sloan telescope uses a wide field of view telescope with an aperture of 2.5 meters, Photometric system Five filters located in u, g, r, i and z bands are used to photograph the celestial bodies. These photos are processed to generate a list of objects, including various parameters of the observed objects, such as whether they are point shaped or extended. If the latter is the case, the object may be a galaxy, and their brightness on the CCD, which is different from the the magnitude of In addition, astronomers also select some targets for spectral observation.

13. Wilkinson cosmic microwave anisotropy Exploration satellite

NASA launched the Wilkinson Cosmic Microwave Anisotropy Detection Satellite in July 2001（ WMAP ）, used to study the cosmic microwave background and Big Bang Radiation of leftovers. WMAP drew the first clear Cosmic microwave background map Thus, we can accurately determine the age of the universe to 13.7 billion years. WMAP's goal is to find cosmic microwave Background radiation The tiny difference between the temperatures helps test various theories about the creation of the universe. It is the successor of COBE and one of the intermediate explorer satellite series. WMAP is named after David Wilkinson, a forerunner of cosmic background radiation.

14、 Swifts Observation satellite

Swift observation satellite was launched in 2004, mainly for research Gamma burst Phenomenon. "Swift" can automatically observe the gamma storm phenomenon in just one minute. It has found hundreds of gamma bursts. "Swift" satellite is actually a Gamma ray burst Origin and exploration Early universe International Multiband observatory. It mainly consists of three parts: Gamma ray , X-ray ultraviolet rays And light waves solar flare 。 During years of operation, Swift has captured 10 times angular velocity Among the gamma ray bursts in operation, the shortest one lasted only 50 milliseconds. Swift satellite can detect independent star parameters beyond 12 billion light-years.

Space telescope

Announce

edit

Beijing Time On October 13, 2008, the US MSNBC website announced eight great space telescopes up to 2008. These telescopes that have entered space in the past 20 years are like "the eye of space", helping people have a clearer understanding of the universe.^[1]

1. Hubble Space Telescope

Time of launch: 1990

hubble space telescope It was launched in 1990. Over the past 20 years, this remarkable telescope has changed our understanding of the universe, and has presented a large number of wonderful space photos to the public. However, the Hubble telescope suffered from hardware failure, which made it unable to communicate with the ground. But NASA is working out a plan to revive the "big observatory", so that the "Hubble" telescope will be in service until at least 2013.

2. Compton Gamma Ray Space Telescope

Time of launch: 1991

Main function: search for high-energy gamma rays

Some of the most violent events in the universe are invisible to the naked eye. They occur in a spectral environment called gamma rays. Gamma ray is the most energetic photon in electromagnetic spectrum. The Compton Gamma Ray Space Telescope, weighing 17 tons, passed by Atlantis in 1991 space shuttle It is launched to observe high-energy rays in the universe. Compton's advanced instruments revealed the distribution of high-energy gamma ray bursts to the world. In 2000, in gyroscope After failure, Compton Was safely off track.

three Chandra X-ray Space Telescope

Time of launch: 1999

Main functions: observing black holes and Supernova

For a long time, science fiction writers like to endow fictional superheroes such as "Superman" with X-ray vision, which enables them to see clearly what ordinary people cannot see. After the Chandra X - ray Space Telescope was launched in 1999, real world astronomy had this super power. Chandra telescope is used to observe objects such as black holes and supernovae in the form of high-energy light. It has a 340 year history supernova remnant “ Cassiopeia A ”It reveals to astronomers that such exploding stars may be an important source of cosmic rays. Cosmic rays bombard the earth continuously High-energy particle 。

4. XMM Newton X-ray space telescope

Time of launch: 1999

Main function: continuous observation of deep space

December 1999, multiple lenses X-ray observation The satellite (now called XMM Newton) was launched, and European astronomers have their own X-ray observatory since then. This satellite is equipped with three X-ray telescope , is famous for its strange telescope flight orbit, which allows it to observe deep space for a long time and continuously. XMM Newton has made many breakthroughs in European astronomy, such as the observation of the largest scale in the distant universe Galaxy cluster 。 This huge galaxy cluster proves the existence of a mysterious force called dark energy. It is said that dark energy accelerates the expansion of the universe. Scientists say that such a huge galaxy cluster may be Early universe Formed.

five Wilkinson Microwave Anisotropy Detector

Time of launch: 2001

Main function: early detection Cosmic structure

About 380000 years after the Big Bang, the universe released a large amount of Radiant heat This radiant heat is called cosmic microwave background radiation. According to astronomical theory, the universe originated from the Big Bang. NASA launched a spacecraft in 1992 to detect small changes in the cosmic microwave background radiation. The Wilkinson Microwave Anisotropy Detector was launched in 2001 and has been studying more subtle changes in the cosmic microwave background radiation for many years, giving scientists a preliminary understanding of the state of the universe after the Big Bang. In 2003, NASA released an early image based on data from the Wilkinson Microwave Anisotropy Probe Cosmic map 。 these ones here Data confirmation The universe has a history of 13.7 billion years.

six Spitzer Space Telescope

Time of launch: 2003

Main function: penetration Interstellar gas And dust

I wonder if you have ever climbed to the top of the mountain, only to see smoke around the scene. Tight interstellar gas and dust create similar problems for astronomers trying to understand distant stars and galaxies. Spitzer Space Telescope launched in 2003 infrared light , solved this problem for astronomers. Infrared light is related to some heat electromagnetic radiation This heat can not be blocked by gas clouds. Through the camera carried by the Spitzer Space Telescope, astronomers Planetary system And star forming regions (such as those on the left W5 Area).

seven Fermi Gamma Ray Space Telescope

Launch time: 2008

Main function: study black holes and unveil the mystery of dark matter

Black holes are called eddies in space, attracting everything around them. But when the black hole engulfs Sidereal time They also spew out gas emitting gamma rays at a speed close to the speed of light. Why does this happen? The Fermi Gamma Ray Space Telescope launched in July 2008 may reveal this mystery. The goal of this telescope is to study high-energy radiation. In addition, it may also reveal the mystery of dark matter, which will help to further understand the most extreme environment Substances that we have never heard of. Dark matter is the source of gamma ray bursts.

8. James Weber Space Telescope

Launch time: 2013

Main function: search for the earliest stars and galaxies in the universe

James Webb The space telescope is scheduled to be launched in 2013, and will use its 7 times the focusing capacity of the Hubble Space Telescope to explore space. The James Webb Space Telescope is regarded as the "successor" of Hubble. Its huge light gathering ability will make it possible to observe the first stars and galaxies formed in the universe. The core of the James Weber Telescope is 18 hexagonal mirrors, which will act together to focus on objects in the distant, young universe. The latest research findings may provide information from the formation of stars, galaxies, planets to solar system Evolution and other clues.

Kepler space telescope ^[1]

Kepler Mission is an American country Aerospace The bureau is designed to find planets orbiting other stars Space telescope 。 use NASA Space for development Photometer It is estimated that it will take 3.5 years to make a detour sunlight Observe the luminosity of 100000 stars in the orbit of Transit To detect planets). To honor German astronomers Johannes Kepler This mission is called Kepler Space Telescope. Kepler is NASA's low-cost discovery program focused on science. NASA's Ames Research Center is responsible for this mission Competent Authority , provide key researchers and be responsible for Ground system Development, task execution and scientific data Analysis of.

After months of hard work, American Space The Administration announced on August 15, 2013 that it would give up repairing the "Kepler" space telescope. Kepler ends the search solar system Outside terrestrial planet But it may still be used for other scientific research work.

The size of a telescope is mainly measured by its aperture. In order to make more careful research and observation of celestial bodies, and to find more faint celestial bodies, people have been working hard to increase the aperture of telescopes for many years. However, different telescopes have different requirements in aperture. The largest reflecting telescope in the world is a 6m telescope built by the Soviet Union in 1975. It has been called“ The most in the world ”Of Palomar Observatory 5 meter reflecting telescope. The total weight of its rotating parts is 800 tons, which is also 200 tons heavier than that of the United States. In 1978, an American set with a combined caliber equivalent to 4.5 meters Multi mirror telescope Test run. This telescope consists of six Cassegrain telescopes with the same aperture of 1.8 meters. 6 telescopes around Central axis Arranged in a hexagon, six beams of concentrated light each pass through one piece Plane mirror Shooting at a hexagonal beam Synthesizer , and then focus six beams of light on a common focus. The advantages of multi mirror telescope are: large aperture, short barrel, small floor area, and low cost. The largest optical telescope is 10 meters in diameter Keck telescope 。

The world's largest refracting telescope was installed at the Taudenburg Observatory in Germany Schmidt telescope , the corrected aperture is 1.35m, and the main mirror aperture is 2m. The German refractor also surpassed the largest Schmidt telescope in the United States. America's two "world's best" telescopes have been taken away one after another.

On October 11, 1957, the world's largest radio telescope was built on the banks of the Yodrell River in England. It was completed ahead of schedule to track the first Soviet satellite launched a week ago.

The earliest telescope in the world was in 1609 Italy The scientist Galileo made it. Therefore, it is also called Galileo telescope. This is a refracting telescope. He used a convex lens crop mirror Concave mirror As an eyepiece, the positive image is observed. Galileo said when talking about the world's first telescope: "Thanks for the telescope, we have been able to keep the celestial bodies away from us Aristotle Nearly 30 to 40 times, so we can identify many things on the celestial body Aristotle Not seen; Apart from other things, these sunspots in the solar system are absolutely invisible to him. So we should treat the celestial bodies and the sun more confidently than Aristotle. "

Novice on the road

Growth task Getting Started with Editing Edit Rule Edit by myself

I have questions

Content query Online Service Official post bar Feedback

Complaints and suggestions

Report bad information Failed to appeal through entries Complaint of infringement information Blocking query and unblocking

Jinggong Network Anbei No. 1100000200001