The best galaxy images from the Hubble Orbital Telescope. This is where the famous Hubble Space Telescope is located. The Hubble Space Telescope's orbit is at an altitude

There are three objects in Earth’s orbit that even people far from astronomy and cosmonautics know about: the Moon, the International Space Station and the Hubble Space Telescope.

There are three objects in Earth’s orbit that even people far from astronomy and cosmonautics know about: the Moon, the International Space Station and the Hubble Space Telescope.

The latter is eight years older than the ISS and also included the Mir Orbital Station. Many people think of it as just a big camera in space. The reality is a little more complicated, and it’s not for nothing that people who work with this unique device respectfully call it a celestial observatory.

The history of Hubble's construction is one of constant overcoming difficulties, the struggle for funding and the search for solutions to unforeseen situations. Hubble's role in science is priceless. It is impossible to compile a complete list of discoveries in astronomy and related fields made thanks to the telescope’s images, so many works refer to the information obtained by it. However, official statistics indicate almost 15 thousand publications.

Story

The idea of ​​placing a telescope in orbit arose almost a hundred years ago. The scientific justification for the importance of building such a telescope was published in the form of an article by astrophysicist Lyman Spitzer in 1946. In 1965, he was made head of the committee of the Academy of Sciences, which determined the objectives of such a project.

In the sixties, it was possible to carry out several successful launches and deliver simpler devices into orbit, and in ’68, NASA gave the green light to Hubble’s predecessor - the LST apparatus, the Large Space Telescope, with a larger mirror diameter - 3 meters versus Hubble’s 2.4 - and an ambitious the task of launching it already in 1972, with the help of the space shuttle then under development. But the estimated project estimate turned out to be too expensive, difficulties arose with money, and in 1974 the funding was completely canceled.

Active lobbying of the project by astronomers, the involvement of the European Space Agency and simplification of the characteristics approximately to those of Hubble made it possible in 1978 to receive funding from Congress in the amount of ridiculous 36 million dollars in terms of total costs, which today is equal to approximately 137 million.

At the same time, the future telescope was named in honor of Edwin Hubble, an astronomer and cosmologist who confirmed the existence of other galaxies, created the theory of the expansion of the Universe and gave his name not only to the telescope, but also to a scientific law and quantity.

The telescope was developed by several companies responsible for different elements, of which the most complex were the optical system, which was developed by Perkin-Elmer, and the spacecraft, which was created by Lockheed. The budget has already grown to $400 million.

Lockheed delayed the creation of the device for three months and exceeded its budget by 30%. If you look at the history of the construction of devices of similar complexity, this is a normal situation. For Perkin-Elmer, things were much worse. The company polished the mirror using innovative technology until the end of 1981, greatly exceeding the budget and ruining relations with NASA. Interestingly, the blank of the mirror was made by Corning, which today produces Gorilla Glass, which is actively used in phones.

By the way, Kodak was contracted to make a spare mirror using traditional polishing methods if problems arise with the polishing of the main mirror. Delays in building other components slowed the process so much that NASA was quoted as saying that schedules were "uncertain and changing daily."

The launch became possible only in 1986, but due to the Challenger disaster, shuttle launches were suspended for the duration of modifications.

Hubble was stored piece by piece in special nitrogen-flushed chambers at a cost of six million dollars a month.

As a result, on April 24, 1990, the Discovery shuttle launched into orbit with the telescope. At this point, $2.5 billion had been spent on Hubble. Total costs today are approaching ten billion.

Since launch, several dramatic events involving Hubble have occurred, but the main one happened at the very beginning.

When, after being launched into orbit, the telescope began its work, it turned out that its sharpness was an order of magnitude lower than calculated. Instead of a tenth of an arcsecond, it was a whole second. After several checks, it turned out that the telescope mirror was too flat at the edges: it did not coincide by as much as two micrometers with the calculated one. The aberration resulting from this literally microscopic defect made most planned studies impossible.

A commission was assembled, whose members found the reason: the incredibly accurately calculated mirror had been polished incorrectly. Moreover, even before the launch, the same deviations were shown by the pair of null correctors used in the tests - devices that were responsible for the desired surface curvature.

But then they did not trust these readings, relying on the readings of the main zero-corrector, which showed the correct results and according to which the grinding was carried out. And one of the lenses of which, as it turned out, was installed incorrectly.

Human factor

It was technically impossible to install a new mirror directly in orbit, and lowering the telescope and then bringing it back up again was too expensive. An elegant solution was found.

Yes, the mirror was made incorrectly. But it was done incorrectly with very high precision. The distortion was known, and all that remained was to compensate for it, for which a special COSTAR correction system was developed. It was decided to install it as part of the first expedition to service the telescope.

Such an expedition is a complex ten-day operation with astronauts going into outer space. It’s impossible to imagine a more futuristic job, and it’s just maintenance. There were four expeditions in total during the operation of the telescope, with two flights as part of the third.

On December 2, 1993, the space shuttle Endeavor, for which this was the fifth flight, delivered the astronauts to the telescope. They installed Costar and replaced the camera.

Costar corrected the spherical aberration of the mirror, playing the role of the most expensive glasses in history. The optical correction system fulfilled its task until 2009, when the need for it disappeared due to the use of its own corrective optics in all new devices. It gave up precious space in the telescope to the spectrograph and took pride of place in the National Air and Astronautics Museum after being dismantled as part of the fourth Hubble servicing mission in 2009.

Control

The telescope is controlled and monitored in real time 24/7 from a control center in Greenbelt, Maryland. The center’s tasks are divided into two types: technical (maintenance, management and condition monitoring) and scientific (selection of objects, preparation of tasks and direct data collection). Every week, Hubble receives more than 100,000 different commands from Earth: these are orbit-correcting instructions and tasks for photographing space objects.

At the MCC, the day is divided into three shifts, each of which is assigned a separate team of three to five people. During expeditions to the telescope itself, the staff increases to several dozen.

Hubble is a busy telescope, but even its busy schedule allows it to help absolutely anyone, even a non-professional astronomer. Every year, the Institute for Space Research using the Space Telescope receives thousands of applications for booking time from astronomers from different countries.

About 20% of applications receive approval from an expert commission and, according to NASA, thanks to international requests, plus or minus 20 thousand observations are carried out annually. All these requests are connected, programmed and sent to Hubble from the same center in Maryland.

Optics

Hubble's main optics are based on the Ritchie-Chrétien system. It consists of a round, hyperbolically curved mirror with a diameter of 2.4 m with a hole in the center. This mirror reflects onto a secondary mirror, also of a hyperbolic shape, which reflects a beam suitable for digitization into the central hole of the primary one. All kinds of filters are used to filter out unnecessary parts of the spectrum and highlight the necessary ranges.

Such telescopes use a system of mirrors, not lenses, as in cameras. There are many reasons for this: temperature differences, polishing tolerances, overall dimensions and the lack of beam loss within the lens itself.

The basic optics on Hubble have not changed since the beginning. And the set of various instruments that use it was completely changed over several maintenance expeditions. Hubble was updated with instrumentation, and during its existence thirteen different instruments worked there. Today he carries six, one of which is in hibernation.

Wide-angle and planetary cameras of the first and second generations, and the Wide-angle camera of the third now, were responsible for photographs in the optical range.

The potential of the first WFPC was never realized due to problems with the mirror. And the expedition of 1993, having installed Kostar, at the same time replaced it with the second version.

The WFPC2 camera had four square sensors, the images from which formed a large square. Almost. One matrix - just a “planetary” one - received an image with a higher magnification, and when the scale was restored, this part of the image captured less than a sixteenth of the total square instead of a quarter, but in a higher resolution.

The remaining three matrices were responsible for “wide-angle”. This is why full camera shots look like a square with 3 blocks removed from one corner, and not because of problems with loading files or other problems.

WFPC2 was replaced by WFC3 in 2009. The difference between them is well illustrated by the re-shot Pillars of Creation, about which later.

In addition to the optical and near-infrared range with a wide-angle camera, Hubble sees:

• using the STIS spectrograph in the near and far ultraviolet, as well as from visible to near infrared;
• there, using one of the ACS channels, the other channels of which cover a huge frequency range from infrared to ultraviolet;
• weak point sources in the ultraviolet range with the COS spectrograph.

Pictures

Hubble's images are not exactly photographs in the usual sense. A lot of information is not available in the optical range. Many space objects actively emit in other ranges. Hubble is equipped with many devices with a variety of filters that allow them to capture data that astronomers later process and can summarize into a visual image. The richness of colors is provided by different ranges of radiation from stars and particles ionized by them, as well as their reflected light.

There are a lot of photographs, I’ll tell you only about a few of the most exciting ones. All photographs have their own ID, which can be easily found on the Hubble website spacetelescope.org or directly on Google. Many of the pictures are on the site in high resolution, but here I leave screensize versions.

Pillars of Creation

ID: opo9544a

Hubble took his most famous shot on April 1, 1995, without being distracted from his smart work on April Fool's Day. These are the Pillars of Creation, so named because stars are formed from these accumulations of gas, and because they resemble them in shape. The picture shows a small piece of the central part of the Eagle Nebula.

This nebula is interesting because the large stars in its center partially dispelled it, and even just from the side of the Earth. Such luck allows you to look into the very center of the nebula and, for example, take the famous expressive photograph.

Other telescopes also photographed this region in different ranges, but in optical the Pillars come out most expressively: ionized by the very stars that dispelled part of the nebula, the gas glows in blue, green and red, creating beautiful iridescence.

In 2014, the Pillars were re-shot with updated Hubble equipment: the first version was filmed by the WFPC2 camera, and the second by WFC3.

ID: heic1501a

Rose made of galaxies

ID: heic1107a

The object Arp 273 is a beautiful example of communication between galaxies that are close to each other. The asymmetrical shape of the upper one is a consequence of the so-called tidal interactions with the lower one. Together they form a grandiose flower, presented to humanity in 2011.

Magic Galaxy Sombrero

ID: opo0328a

Messier 104 is a majestic galaxy that looks like it was invented and painted in Hollywood. But no, the beautiful one hundred and fourth is located on the southern outskirts of the constellation Virgo. And it is so bright that it is visible even through home telescopes. This beauty posed for Hubble in 2004.

New infrared view of the Horsehead Nebula - Hubble 23rd Anniversary image

ID: heic1307a

In 2013, Hubble re-imaged Barnard 33 in the infrared spectrum. And the gloomy Horsehead Nebula in the constellation Orion, almost opaque and black in the visible range, appeared in a new light. That is, the range.

Before this, Hubble had already photographed it in 2001:

ID: heic0105a

Then she won the online vote for the anniversary object for eleven years in orbit. Interestingly, even before Hubble's photographs, the Horse's Head was one of the most photographed objects.

Hubble captures star-forming region S106

ID: heic1118a

S106 is a star-forming region in the constellation Cygnus. The beautiful structure is due to the ejecta of a young star, which is shrouded in donut-shaped dust at the center. This dust curtain has gaps at the top and bottom, through which the material of the star breaks out more actively, forming a shape reminiscent of the well-known optical illusion. The photo was taken at the end of 2011.

Cassiopeia A: the colorful aftermath of a star's death

ID: heic0609a

You've probably heard about supernova explosions. And this picture clearly shows one of the scenarios for the future fate of such objects.

The photo from 2006 shows the consequences of the explosion of the star Cassiopeia A, which happened right in our galaxy. A wave of matter scattering from the epicenter, with a complex and detailed structure, is clearly visible.

Hubble image of Arp 142

ID: heic1311a

And again, a picture demonstrating the consequences of the interaction of two galaxies that found themselves close to one another during their Ecumenical journey.

NGC 2936 and 2937 collided and influenced each other. This is an interesting event in itself, but in this case another aspect has been added: the current shape of the galaxies resembles a penguin with an egg, which works as a big plus for the popularity of these galaxies.

In a cute picture from 2013, you can see traces of the collision that occurred: for example, the penguin's eye is formed, for the most part, by bodies from the egg galaxy.

Knowing the age of both galaxies, we can finally answer what came first: the egg or the penguin.

A butterfly emerging from the remnants of a star in the planetary nebula NGC 6302

ID: heic0910h

Sometimes gas streams heated to 20 thousand degrees, flying at a speed of almost a million km/h look like the wings of a fragile butterfly, you just need to find the right angle. Hubble didn’t have to look, the nebula NGC 6302 - also called the Butterfly or Beetle nebula - itself turned towards us in the right direction.

These wings are created by the dying star of our galaxy in the constellation Skopio. The gas flows get their wing shape again due to the ring of dust around the star. The same dust covers the star itself from us. It is possible that the ring was formed by the star losing matter along the equator at a relatively low rate, and the wings by a more rapid loss from the poles.

Deep Field

There are several Hubble images that have Deep Field in the title. These are frames with a huge multi-day exposure time, showing a small piece of the starry sky. To remove them, I had to very carefully select an area suitable for such exposure. It should not have been blocked by the Earth and the Moon, there should have been no bright objects nearby, and so on. As a result, Deep Field became very useful footage for astronomers, from which they can study the processes of formation of the universe.

The most recent such frame - the Hubble Extreme Deep Field of 2012 - is quite boring to the average eye - this is an unprecedented shooting with a shutter speed of two million seconds (~23 days), showing 5.5 thousand galaxies, the dimmest of which have a brightness of ten billions less than the sensitivity of human vision.

ID: heic1214a

And this incredible picture is freely available on the Hubble website, showing everyone a tiny part of 1/30,000,000 of our sky, on which thousands of galaxies are visible.

Hubble (1990 – 203_)

Hubble is due to leave orbit after 2030. This fact seems sad, but in fact the telescope has exceeded the duration of its original mission by many years. The telescope was modernized several times, the equipment was changed to more and more advanced ones, but these improvements did not affect the main optics.

And in the coming years, humanity will receive a more advanced replacement for the old fighter when the James Webb Telescope is launched. But even after this, Hubble will continue to work until it fails. Incredible amounts of work by scientists, engineers, astronauts, people in other professions and money from American and European taxpayers were invested in the telescope.

In response, humanity has an unprecedented base of scientific data and art objects that help to understand the structure of the universe and create a fashion for science.

It is difficult to understand the value of Hubble for non-astronomers, but for us it is a wonderful symbol of human achievement. Not without problems, with a complex history, the telescope has become a successful project, which, hopefully, will work for the benefit of science for more than ten years. published

If you have any questions on this topic, ask them to the experts and readers of our project.

The Hubble Telescope, named after the American astronomer Edwin Hubble (1889-1953), was launched into low Earth orbit on April 24, 1990. During its work, more than a million images of stars, planets, galaxies, nebulae and other space objects were obtained.

The Earth's atmosphere is opaque, so if Hubble were located on the surface of our planet, it would see ten times worse.

Immediately after the telescope was launched, it turned out that its main mirror had a defect, which is why the sharpness and resolution of the resulting images were significantly worse than expected. Over the entire history of the telescope, five expeditions to service it took place. The main task of the first flight to Hubble was, of course, to eliminate the mirror defect by installing corrective optics. This was one of the most difficult expeditions in the entire history of our exploration of extraterrestrial space. The astronauts completed five long-duration spacewalks; several cameras, solar panels, guidance systems were replaced... At the end of the work, the orbit was adjusted, since due to friction with the air when moving in the upper layers of the atmosphere, a loss of altitude occurred. The mission was successful and the images obtained after its completion were very good. On subsequent expeditions, planned maintenance work and replacement of equipment with more modern equipment were carried out. For a long time, the fifth flight to Hubble was in doubt.

After the Columbia disaster in March 2003, maintenance work on the telescope was temporarily suspended. NASA decided that every space shuttle should be able to get to the ISS if technical problems arise.

However, the need for maintenance work is clearly overdue. NASA was faced with a serious question: take risks or leave things as they are? The fifth flight to Hubble took place against all odds in the spring of 2009 after a new administrator at NASA. It was decided that this expedition to Hubble would be the last.

How do you get bright and colorful images from Hubble?

Hubble takes pictures of space objects in various ranges from infrared to ultraviolet, the output is black and white photographs of very good quality and resolution. Where do these bright color images come from that first appear on the NASA website and then wander all over the Internet? The answer is quite banal: Photoshop. The photo processing process is complex and time-consuming, don’t be fooled by the two-minute length of the video. This is what it looks like:

The most famous images from Hubble:

Pillars of Creation

The Pillars of Creation or Elephant Trunks are a collection of star dust and gas in the Eagle Nebula (7000 light years from Earth).

Andromeda Galaxy, 2.5 million light years from Earth:

Galaxy M83, 15 million light years from Earth:

The Crab Nebula is the result of a supernova explosion in 1054 AD; in the center of the nebula there is a neutron star (mass of the same order as that of our Sun, size - like a small city).

Galaxy NGC 5194, 23 million light years from Earth:

Bottom left is a supernova that exploded in 1994 on the outskirts of a spiral galaxy.

Sombrero Galaxy, 30 million light years from Earth:

The Omega Nebula in the constellation Sagittarius, 5 thousand light years from Earth:

The best pictures from the Hubble telescope. You can put it on full screen and enjoy:

Background, concepts, early projects

The first mention of the concept of an orbital telescope is found in the book “Rocket in Interplanetary Space” by Hermann Oberth. "Die Rakete zu den Planetenraumen" ).

In 1946, American astrophysicist Lyman Spitzer published the article “The Astronomical Advantages of an Extraterrestrial Observatory.” Astronomical advantages of an extra-terrestrial observatory ). The article highlights two main advantages of such a telescope. Firstly, its angular resolution will be limited only by diffraction, and not by turbulent flows in the atmosphere; at the time, the resolution of ground-based telescopes was 0.5 to 1.0 arcsecond, while the theoretical diffraction resolution limit for a telescope with a 2.5 meter mirror is about 0.1 second. Secondly, the space telescope could observe in the infrared and ultraviolet ranges, in which the absorption of radiation by the earth's atmosphere is very significant.

Spitzer devoted a significant portion of his scientific career to advancing the project. In 1962, a report published by the US National Academy of Sciences recommended that the development of an orbiting telescope be included in the space program, and in 1965 Spitzer was appointed head of a committee tasked with defining the scientific objectives for a large space telescope.

Space astronomy began to develop after the end of World War II. In 1946, the ultraviolet spectrum of the Sun was obtained for the first time. An orbiting telescope for solar research was launched by the UK in 1962 as part of the Ariel program, and in 1966 NASA launched the first orbital observatory OAO-1 into space. Orbiting Astronomical Observatory ). The mission was unsuccessful due to battery failure three days after launch. In 1968, OAO-2 was launched, which made observations of ultraviolet radiation from stars and galaxies until 1972, significantly exceeding its design life of 1 year.

The OAO missions provided a clear demonstration of the role that orbiting telescopes could play, and in 1968 NASA approved plans to build a reflecting telescope with a 3-meter diameter mirror. The project was codenamed LST. Large Space Telescope). The launch was planned for 1972. The program emphasized the need for regular manned expeditions to maintain the telescope in order to ensure long-term operation of the expensive instrument. The Space Shuttle program, which was developing in parallel, gave hope for obtaining corresponding opportunities.

The struggle to finance the project

Due to the success of the JSC program, there is a consensus in the astronomical community that building a large orbiting telescope should be a priority. In 1970, NASA established two committees, one to study and plan technical aspects, the second to develop a scientific research program. The next major obstacle was financing the project, the costs of which were expected to exceed the cost of any ground-based telescope. The US Congress questioned many of the proposed estimates and significantly cut the appropriations, which initially involved large-scale research into the instruments and design of the observatory. In 1974, as part of a program of budget cuts initiated by President Ford, Congress completely canceled funding for the project.

In response, astronomers launched a broad lobbying campaign. Many scientists met personally with senators and congressmen, and several large mailings of letters were also carried out in support of the project. The National Academy of Sciences published a report emphasizing the importance of building a large orbiting telescope, and as a result, the Senate agreed to allocate half of the budget originally approved by Congress.

Financial problems led to cutbacks, chief among them the decision to reduce the diameter of the mirror from 3 to 2.4 meters to reduce costs and achieve a more compact design. The project of a telescope with a one and a half meter mirror, which was supposed to be launched for the purpose of testing and testing the systems, was also canceled, and a decision was made to cooperate with the European Space Agency. ESA agreed to participate in the financing, as well as provide a number of instruments and solar panels for the observatory, in exchange for European astronomers reserving at least 15% of the observing time. In 1978, Congress approved $36 million in funding, and full-scale design work began immediately thereafter. The launch date was planned for 1983. In the early 1980s, the telescope was named after Edwin Hubble.

Organization of design and construction

The work on creating the space telescope was divided among many companies and institutions. The Marshall Space Center was responsible for the development, design and construction of the telescope, the Goddard Space Flight Center was responsible for the overall management of the development of scientific instruments and was chosen as the ground control center. The Marshall Center contracted with Perkin-Elmer to design and manufacture the telescope's optical system. Optical Telescope Assembly, OTA ) and precision guidance sensors. Lockheed Corporation received a contract to build the spacecraft for the telescope.

Manufacturing of the optical system

Polishing the telescope's primary mirror, Perkin-Elmer Laboratory, May 1979.

The mirror and the optical system as a whole were the most important parts of the telescope design, and particularly stringent requirements were placed on them. Typically, telescope mirrors are made to a tolerance of about one-tenth the wavelength of visible light, but since the space telescope was intended to observe in the ultraviolet to near-infrared range, and the resolution had to be ten times higher than that of ground-based instruments, the tolerance for its manufacture The main mirror was set to 1/20 the wavelength of visible light, or approximately 30 nm.

The Perkin-Elmer company intended to use new computer numerical control machines to produce a mirror of a given shape. Kodak was contracted to produce a replacement mirror using traditional polishing methods in case of unforeseen problems with unproven technologies (the Kodak-manufactured mirror is currently on display at the museum). Work on the main mirror began in 1979, using glass with an ultra-low coefficient of expansion. To reduce weight, the mirror consisted of two surfaces - lower and upper, connected by a lattice structure of a honeycomb structure.

Telescope backup mirror, Smithsonian Air and Space Museum, Washington.

Work on polishing the mirror continued until May 1981, but the original deadlines were missed and the budget was significantly exceeded. NASA reports from the period expressed doubts about the competence of Perkin-Elmer's management and its ability to successfully complete a project of such importance and complexity. To save money, NASA canceled the backup mirror order and moved the launch date to October 1984. The work was finally completed by the end of 1981 after applying a reflective coating of aluminum 75 nm thick and a protective coating of magnesium fluoride 25 nm thick.

Despite this, doubts about Perkin-Elmer's competence remained as the completion date for the remaining components of the optical system was constantly pushed back and the project budget grew. NASA described the company's schedule as "uncertain and changing daily" and delayed the telescope's launch until April 1985. However, the deadlines continued to be missed, the delay grew by an average of one month every quarter, and at the final stage it grew by one day every day. NASA was forced to postpone the launch twice more, first to March and then to September 1986. By that time, the total project budget had grown to $1.175 billion.

Spacecraft

The initial stages of work on the spacecraft, 1980.

Another difficult engineering problem was creating a spacecraft for the telescope and other instruments. The main requirements were protection of the equipment from constant temperature changes during heating from direct sunlight and cooling in the Earth's shadow, and particularly precise orientation of the telescope. The telescope is mounted inside a lightweight aluminum capsule, which is covered with multi-layer thermal insulation to ensure a stable temperature. The rigidity of the capsule and the mounting of instruments is provided by an internal carbon fiber space frame.

Although the spacecraft was more successful than the optical system, Lockheed also ran slightly behind schedule and over budget. By May 1985, cost overruns amounted to about 30% of the original volume, and the lag behind the plan was 3 months. A report prepared by the Marshall Space Center noted that the company did not show initiative in carrying out work, preferring to rely on instructions from NASA.

Research coordination and flight control

In 1983, after some confrontation between NASA and the scientific community, it was established. The institute is run by the Universities Association for Astronomical Research. Association of Universities for Research in Astronomy ) (English) AURA) and is located on the campus of Johns Hopkins University in Baltimore, Maryland. Hopkins University is one of 32 American universities and foreign institutions that are members of the association. The Space Telescope Science Institute is responsible for organizing scientific work and making data available to astronomers, functions that NASA wanted to keep under its own control but scientists chose to outsource to academic institutions.

The European Space Telescope Coordination Center was founded in 1984 in Garching, Germany to provide similar facilities to European astronomers.

Flight control was entrusted to the Goddard Space Flight Center. Goddard Space Flight Center), which is located in Greenbelt, Maryland, 48 kilometers from the Space Telescope Science Institute. The functioning of the telescope is monitored round-the-clock in shifts by four groups of specialists.

Technical support is provided by NASA and contracting companies through the Goddard Center.

Launch and getting started

The launch of the Discovery shuttle with the Hubble telescope on board.

The telescope was originally scheduled to launch into orbit in October 1986, but the Challenger disaster on January 28 halted the Space Shuttle program for several years, and the launch had to be postponed.

The forced delay allowed a number of improvements to be made: solar panels were replaced with more efficient ones, the on-board computer complex and communication systems were modernized, and the design of the aft protective casing was changed in order to facilitate servicing the telescope in orbit.

All this time, parts of the telescope were stored in rooms with an artificially purified atmosphere, which further increased the costs of the project.

After the resumption of shuttle flights in 1988, the launch was finally scheduled for 1990. Before launch, dust accumulated on the mirror was removed using compressed nitrogen, and all systems were thoroughly tested.

Devices installed at the time of launch

At the time of launch, five scientific instruments were installed on board:

• Wide-angle and planetary camera Wide Field and Planetary Camera ) (English) Wide Field and Planetary Camera, WFPC ). The camera was constructed at NASA's Jet Propulsion Laboratory. It was equipped with a set of 48 light filters to highlight areas of the spectrum that are of particular interest for astrophysical observations. The device had 8 CCD matrices, divided between two cameras, each of which used 4 matrices. The wide-angle camera had a larger field of view, while the planetary camera had a longer focal length and therefore provided greater magnification.

• Camera for shooting dim objects Faint Object Camera) (English) Faint Object Camera, FOC). The instrument was developed by ESA. The camera was intended for shooting objects in the ultraviolet range with high resolution up to 0.05 sec.

• Spectrograph of dim objects Faint Object Spectrograph) (English) Faint Object Spectrograph, FOS ). Intended for studying particularly dim objects in the ultraviolet range.

• High speed photometer High Speed ​​Photometer) (English) High Speed ​​Photometer, HSP). Developed at the University of Wisconsin, it was intended for observing variable stars and other objects with varying brightness. It could take up to 10,000 measurements per second with an error of about 2%.

Main mirror defect

Already in the first weeks after the start of work, the resulting images demonstrated a serious problem in the telescope’s optical system. Although the image quality was better than that of ground-based telescopes, Hubble could not achieve the desired sharpness, and the resolution of the images was significantly worse than expected. The images had a radius of over one solid second instead of focusing into a circle 0.1 second in diameter, according to the specification.

Image analysis showed that the source of the problem was the incorrect shape of the primary mirror. Even though it was perhaps the most precisely calculated mirror ever made, with a tolerance of no more than 1/20th the wavelength of visible light, it was manufactured too flat around the edges. The deviation from the specified surface shape was only 2 microns, but the result was catastrophic - strong spherical aberration, an optical defect in which light reflected from the edges of the mirror is focused at a point different from the one at which light reflected from the center of the mirror is focused.

The effect of the defect on astronomical research depended on the specific type of observation - the scattering characteristics were sufficient to obtain unique high-resolution observations of bright objects, and spectroscopy was also largely unaffected. However, the loss of a significant portion of the light output due to defocus significantly reduced the telescope's suitability for observing dim objects and obtaining high-contrast images. This meant that almost all cosmological programs became simply impossible, since they required observations of particularly dim objects.

Causes of the defect

By analyzing images of point light sources, astronomers found that the conical constant of the mirror was −1.0139, instead of the required −1.00229. The same number was obtained by testing null correctors (instruments that allow high-precision measurement of the curvature of a polished surface) used by Perkin-Elmer, as well as from analyzing interferograms obtained during ground testing of the mirror.

The commission headed by Liu Allen Lew Allen), director of the Jet Propulsion Laboratory, found that the defect arose as a result of an error during installation of the main null corrector, the field lens of which was shifted by 1.3 mm relative to the correct position. The shift occurred due to the fault of the technician who assembled the device. He made a mistake when working with a laser meter, which was used to accurately place the optical elements of the device, and when, after the installation was completed, he noticed an unexpected gap between the lens and the structure supporting it, he simply inserted an ordinary metal washer.

While polishing the mirror, its surface was checked using two other null correctors, each of which correctly indicated the presence of spherical aberration. These checks were specifically designed to exclude serious optical defects. Despite clear quality control instructions, the company ignored the measurement results, preferring to believe that the two null correctors were less accurate than the main one, whose readings indicated the ideal shape of the mirror.

The commission laid the blame for what happened primarily on the performer. The relationship between the optical company and NASA deteriorated significantly during work on the telescope due to constant schedule slippages and cost overruns. NASA determined that the company did not treat the mirror work as a core part of its business and believed that the order could not be transferred to another contractor once work began. Although the commission criticized the company severely, NASA also bore some responsibility, primarily for its failure to detect serious quality control problems and violations of procedures on the part of the contractor.

Looking for a solution

Since the telescope's design initially included on-orbit servicing, scientists immediately began searching for a potential solution that could be applied during the first technical mission, planned for 1993. Although Kodak had completed a replacement mirror for the telescope, replacing it in space was not possible, and removing the telescope from orbit to replace the mirror on Earth would have been too time-consuming and expensive. The fact that the mirror was precision polished to an irregular shape led to the idea of ​​developing a new optical component that would perform a transformation equivalent to the error, but with the opposite sign. The new device would work like telescope glasses, correcting spherical aberration.

Due to the difference in instrument design, it was necessary to develop two different correction devices. One was intended for the Wide Format and Planetary Camera, which had special mirrors that redirected light to its sensors, and correction could be carried out through the use of specially shaped mirrors that would completely compensate for the aberration. A corresponding change was included in the design of the new Planetary Chamber. Other instruments did not have intermediate reflective surfaces, and thus required an external correction device.

Optical correction system (COSTAR)

The system designed to correct spherical aberration is called COSTAR. COSTAR) and consisted of two mirrors, one of which compensated for the defect. To install COSTAR on the telescope, it was necessary to dismantle one of the instruments, and the scientists decided to sacrifice a high-speed photometer.

During the first three years of operation, before the installation of corrective devices, the telescope made a large number of observations. In particular, the defect did not have a large effect on the spectroscopic measurements. Despite the experiments being canceled due to the defect, many important scientific results were achieved, including new algorithms for improving image quality using deconvolution.

Telescope Maintenance

Hubble is serviced during spacewalks from reusable spacecraft such as the Space Shuttle.

A total of four expeditions were carried out to service the Hubble telescope:

First expedition

Work on the telescope during the first expedition.

Due to the discovery of a defect in the mirror, the importance of the first maintenance expedition was especially great, since it had to install corrective optics on the telescope. The Endeavor STS-61 flight took place from December 2-13, 1993, and work on the telescope continued for ten days. The expedition was one of the most difficult in history; it included five long spacewalks.

The high-speed photometer was replaced with an optical correction system, the wide-angle and planetary cameras were replaced with a new model (WFPC2). Wide Field and Planetary Camera 2 )) with an internal optical correction system. The camera had three square CCDs connected at a corner, and a smaller, higher-resolution "planetary" sensor at the fourth corner. Therefore, camera images have the characteristic shape of a chipped square.

STIS has a working range of 115-1000 nm and allows for two-dimensional spectrography, that is, obtaining the spectrum of several objects simultaneously in the field of view.

The flight recorder was also replaced, the thermal insulation was repaired, and the orbit was corrected.

Third Expedition (A)

Expedition 3A (“Discovery” STS-103) took place on December 19-27, 1999, after a decision was made to carry out part of the third servicing program ahead of schedule. This was caused by three of the six guidance system gyros failing. The fourth gyroscope failed several weeks before the flight, rendering the telescope unsuitable for observations. The expedition replaced all six gyroscopes, the precision guidance sensor and the on-board computer. The new computer used a special version of the Intel 80486 processor - with increased resistance to radiation. This made it possible to carry out some of the calculations previously performed on the ground using the on-board complex.

Third Expedition (B)

Hubble in the shuttle's cargo bay before returning to orbit, with the Earth rising in the background. Expedition STS-109.

Expedition 3B (fourth mission) carried out March 1-12, 2002, Columbia flight STS-109. During the expedition, the Faint Object Camera was replaced with the Advanced Survey Camera. Advanced Camera for Surveys) (English) Advanced Camera for Surveys, ACS ) and the functioning of the Near-Infrared Camera and Spectrometer, whose cooling system ran out of liquid nitrogen in 1999, was restored.

ACS consists of three cameras, one of which operates in far ultraviolet, and the others duplicate and improve the capabilities of WFPC2. Partially inoperative since January 29, 2007.

The solar panels were replaced for the second time. The new panels were one-third smaller in area, which significantly reduced losses due to friction in the atmosphere, but at the same time generated 30% more energy, making it possible to operate simultaneously with all instruments installed on board the observatory. The power distribution unit was also replaced, which required a complete shutdown of power on board for the first time since launch.

The work performed significantly expanded the capabilities of the telescope. Two instruments commissioned during the work - ACS and NICMOS - made it possible to obtain images of deep space.

Fourth expedition

The next maintenance mission to replace batteries and gyroscopes, as well as install new and improved instruments, was scheduled for February 2005, but after the disaster of the space shuttle Columbia on March 1, 2003, it was postponed indefinitely, which jeopardized further work. Hubble". Even after shuttle flights resumed, the mission was canceled because it was decided that every shuttle sent into space should be able to reach the ISS if malfunctions were detected, and due to the large difference in the inclination and altitude of the orbits, the shuttle could not dock at the station after telescope visits.

After this mission, the Hubble telescope will have to continue operating in orbit until at least 2014.

Achievements

Over 15 years of operation in low-Earth orbit, Hubble received 700 thousand images of 22 thousand celestial objects - stars, nebulae, galaxies, planets. The data stream that it generates daily during the observation process is about 15 GB. Their total volume, accumulated over the entire operation of the telescope, exceeds 20 terabytes. More than 3,900 astronomers have had the opportunity to use it for observations, and about 4,000 articles have been published in scientific journals. It has been found that, on average, the citation index of astronomical articles based on telescope data is twice as high as that of articles based on other data. Every year, in the list of the 200 most cited articles, at least 10% are works based on Hubble materials. About 30% of works on astronomy in general have a zero citation index, and only 2% of works performed using a space telescope.

However, the price that has to be paid for Hubble's achievements is very high: a special study devoted to studying the impact of various types of telescopes on the development of astronomy found that although work performed using the orbital telescope has a total citation index of 15 times more than a ground-based reflector with a 4-meter mirror, the cost of maintaining a space telescope is 100 times or more higher.

Most significant observations

Telescope access

Any person or organization can apply to work with the telescope—there are no national or academic restrictions. Competition for observation time is very high; usually the total requested time is 6-9 times greater than the actually available time.

A call for applications for observation is announced approximately once a year. Applications are divided into several categories:

• General observations General observer). Most applications that require a routine procedure and duration of observation fall into this category.
• Blitz observations Snapshot observations), observations requiring no more than 45 minutes, including telescope pointing time, make it possible to fill the gaps between general observations.
• Urgent observations Target of Opportunity), to study phenomena that can be observed during a limited, previously known period of time.

In addition, 10% of observation time remains in the so-called “director's reserve”. Astronomers can apply to use the reserve at any time, and it is typically used for observations of unscheduled short-term events such as supernova explosions. Filming of deep space under the Hubble Deep Field and Hubble Ultra Deep Field programs was also carried out at the expense of the director's reserve.

For the first few years, part of the reserve time was allocated to amateur astronomers. Their applications were reviewed by a committee also consisting of the most prominent lay astronomers. The main requirements for the application were the originality of the research and the discrepancy between the topic and the submitted requests of professional astronomers. In total, between 1997 and 1997, 13 observations were made using programs proposed by amateur astronomers. Subsequently, due to budget cuts at the institute, the provision of time to non-professionals was discontinued.

Planning observations

Planning observations is an extremely complex task, since it is necessary to take into account the influence of many factors:

• Because the telescope is in low orbit, which is necessary to provide services, a significant portion of astronomical objects are obscured by the Earth for slightly less than half of the orbital time. There is a so-called "long visibility zone" approximately 90° to the orbital plane, but due to orbital precession the exact direction changes over an eight-week period.
• Due to increased radiation levels, observations are not possible when the telescope flies over the South Atlantic Anomaly.
• The minimum deviation from the Sun is 45° to prevent direct sunlight from entering the optical system, which, in particular, makes observations of Mercury impossible, and direct observations of the Moon and Earth are permissible with precision guidance sensors disabled.
• Because the telescope orbits in the upper atmosphere, whose density varies over time, it is impossible to accurately predict the location of the telescope. The error of a six-week prediction can be up to 4 thousand km. In this regard, precise observation schedules are drawn up just a few days in advance in order to avoid a situation where the object chosen for observation will not be visible at the appointed time.

Transmission, storage and processing of telescope data

Transmission to Earth

Hubble data is first stored in on-board storage devices; at the time of launch, reel-to-reel tape recorders were used in this capacity; during Expeditions 2 and 3A they were replaced by solid-state drives. Then, through the communication satellite system (TDRSS). TDRSS)), located in low orbit, the data is transmitted to the Goddard Center.

Archiving and data access

During the first year from the date of receipt, the data are provided only to the main investigator (applicant for observation), and then placed in a freely accessible archive. The researcher may submit a request to the director of the institute to reduce or increase this period.

Observations made using time from the director's reserve immediately become public domain, as do supporting and technical data.

The data in the archive is stored in instrument format and must undergo a number of transformations before it becomes suitable for analysis. The Space Telescope Institute has developed a software package for automatic data conversion and calibration. Conversions are performed automatically when the data is requested. Due to the large amount of information and the complexity of the algorithms, processing may take a day or more.

Astronomers can also take the raw data and perform this procedure themselves, which is useful when the conversion process differs from the standard one.

The data can be processed using various programs, but the Telescope Institute provides a package STSDAS(Space Telescope Scientific Data Analysis System, English. Space Telescope Science Data Analysis System ). The package contains all the programs necessary for data processing, optimized for working with Hubble information. The package works as a module of the popular astronomy program IRAF.

Public relations

It has always been important for the space telescope project to capture the attention and imagination of the general public, and especially the American taxpayer, who has made the most significant contribution to the funding of Hubble.

One of the most important for public relations is the Hubble Legacy Project. The Hubble Heritage). Its mission is to publish the most visually and aesthetically impressive images obtained by the telescope. The project galleries contain not only original photographs, but also collages and drawings created from them. The project was allocated a small amount of observation time to obtain full color images of objects whose photographing in the visible part of the spectrum was not necessary for research.

In addition, the Space Telescope Institute maintains several websites with images and comprehensive information about the telescope.

In 2000, a Public Relations Bureau was created to coordinate the efforts of various departments. Office for Public Outreach).

In Europe, since 1999, the European Information Center has been involved in public relations. Hubble European Space Agency Information Center ) (English) Hubble European Space Agency Information Centre, HEIC ), established at the European Space Telescope Coordination Centre. The center is also responsible for ESA's educational programs related to the telescope.

The future of Hubble

It is expected that after the repair work carried out by the fourth expedition, Hubble will work in orbit until 2014, when it will be replaced by the James Webb Space Telescope.

Technical data

General view of the telescope.

Orbit parameters

• Inclination: 28.469°.
• Apogee: 571 km.
• Perigee: 565 km.
• Orbital period: 96.2 min.

Spacecraft

• The length of the spacecraft is 13.3 m, the diameter is 4.3 m, the span of solar panels is 12.0 m, the mass is 11,000 kg (with installed instruments about 12,500 kg).
• The telescope is a Ritchie-Chrétien reflector with a mirror diameter of 2.4 m, allowing an optical resolution of the order of 0.1 arcseconds.

Devices

The telescope has a modular structure and contains five compartments for optical instruments. One of the compartments was occupied by a corrective optical system for a long time (1993-2009). Corrective Optics Space Telescope Axial Replacement ) (COSTAR), installed during the first servicing mission in 1993 to compensate for manufacturing inaccuracies in the primary mirror. Since all instruments installed after the telescope's launch have built-in defect correction systems, during the last expedition it became possible to dismantle the COSTAR system and use the compartment to install an ultraviolet spectrograph.

Chronology of installation of instruments on board the space telescope (newly installed instruments are in italics):

	Compartment 1	Compartment 2	Compartment 3	Compartment 4	Compartment 5
Telescope Launch (1990)	Wide Angle and Planetary Camera			Faint Object Spectrograph	High speed photometer
First Expedition (1993)		Goddard High Resolution Spectrograph	Camera for shooting dim objects	Faint Object Spectrograph	COSTAR system
Second Expedition (1993)	Wide-angle and planetary camera - 2		Camera for shooting dim objects		COSTAR system
Third Expedition (B) (2002)	Wide-angle and planetary camera - 2	Recording spectrograph of a space telescope		Camera and multi-object near-infrared spectrometer	COSTAR system
Fourth Expedition (2009)	Wide-angle and planetary camera - 3	Recording spectrograph of a space telescope	Advanced overview camera	Camera and multi-object near-infrared spectrometer	Ultraviolet spectrograph

As noted above, the guidance system is also used for scientific purposes.

Notes

1. Historical review on the official website, part 2 (English)
2. Lyman S. Spitzer. (1979) History of the Space Telescope // Quarterly Journal of the Royal Astronomical Society. V. 20. P. 29
3. Chapter 12. Hubble Space telescope // Dunar A. J., Waring S. P. (1999) Power To Explore-History of Marshall Space Flight Center 1960-1990. U.S. Government Printing Office, ISBN 0-16-058992-4
4. Information on the NASA website (English)
5. Historical review on the official website, part 3 (English)
6. The European Homepage for the NASA/ESA Hubble Space Telescope - Frequently Asked Questions. Retrieved January 10, 2007.
7. Brandt J. C. et al (1994). The Goddard High Resolution Spectrograph: Instrument, goals, and science results // Publications of the Astronomical Society of the Pacific. V. 106., pp. 890-908
8. G. Fritz Benedict, Barbara E. McArthur. (2005) High-precision stellar parallaxes from Hubble Space Telescope fine guidance sensors. Transits of Venus: New Views of the Solar System and Galaxy. Proceedings of IAU Colloquium #196, Ed. D. W. Kurtz. Cambridge University Press. P. 333-346
9. Burrows C. J. et al. (1991) The imaging performance of the Hubble Space Telescope // Astrophysical Journal. V. 369. P. 21
10. Comparison of real and calculated graphs for displaying point objects (English)
11. Allen Commission Report (English) The Hubble Space Telescope Optical Systems Failure Report, 1990, Lew Allen, Chairman, NASA Technical Report NASA-TM-103443
12. Selected Documents in the History of the U.S. Civil Space Program Volume V: Exploring the Cosmos / John M. Logsdon, editor. 2001
13. Jedrzejewski R. I., Hartig G., Jakobsen P., Crocker J. H., Ford H. C. (1994) In-orbit performance of the COSTAR-corrected Faint Object Camera // Astrophysical Journal Letters. V. 435. P. L7-L10
14. Thackeray's Globules in IC 2944. Hubble Heritage. Retrieved January 25, 2009.
15. Trauger J. T., Ballester G. E., Burrows C. J., Casertano S., Clarke J. T., Crisp D. (1994) The on-orbit performance of WFPC2 // Astrophysical Journal Letters. V. 435. P. L3-L6
16. STSci NICMOS pages
17. Guy Gugliotta. Nominee Backs a Review Of NASA's Hubble Decision, Washington Post(April 12, 2005). Retrieved January 10, 2007. (en language)
18. NASA Approves Mission and Names Crew for Return to Hubble (English) NASA, October 31, 2006

The Hubble telescope is probably the most popular and famous object in one way or another connected with space; few people have not heard this name.

Telescope named after the great American scientist Edwin Powell Hubble, whose main achievement was the discovery of the effect of the Expansion of the Universe.

Hubble was launched into Earth orbit in April 1990. At its core, this is not just a telescope - it is a real automatic orbital observatory.

It took an incredible amount of time, resources and financial resources to implement and launch such a complex and large-scale project as Hubble. Apparently, this is why Hubble became a joint project of the two largest space agencies in the world: NASA and ESA(European Space Agency).

Accommodation telescope in space was an absolutely logical step towards its study, since the earth’s atmosphere greatly complicates observation in some ranges (in particular infrared, less so in ultraviolet) and also practically does not allow recording electromagnetic radiation of medium and low intensity. Thus, Hubble takes 7-10 times higher quality images than similar devices on the Earth's surface.

Hubble did not acquire the status of the main “celestial eye” immediately after its launch, because Initially, during the manufacture of optics, in particular the main mirror, the contractors made a serious mistake, which greatly affected the quality of the resulting images. The defect was corrected in 1993 by the first maintenance and repair expedition as a result of the installation of a corrective optical system COSTAR. The installation procedure for this system was one of the most complex operations in the history of astronautics. The result was not long in coming - the quality of images increased by several orders of magnitude and Hubble was ready to conquer new, unknown secrets of space.

a snapshot of the same galaxy before and after installing the COSTAR system

With each of the four subsequent servicing expeditions in 1997, 1999, 2002 and 2009, the space telescope received the latest updates to its technical arsenal, becoming an increasingly sophisticated and versatile tool for exploring the vastness of space. Currently, Hubble has at its disposal the following instruments: wide-angle and planetary cameras, an advanced survey camera, a multi-object near-infrared spectrometer, and an ultraviolet spectrograph. Thanks to its technical arsenal, Hubble has been one way or another involved in the lion's share of space news: discoveries, observations and pictures of the Universe since 1993.

For almost 23 years spent in low-Earth orbit, Hubble has become a legendary telescope. He took several million photographs, made many discoveries, on the basis of which more than one cosmological theory was built. The monthly data flow exceeds 80 Gigabytes, and their total volume has reached 50 Terabytes.

Hubble's most significant observations:

1. Filming the collision of Comet Shoemaker-Levy with Jupiter in 1994.
2. Detailed images of the surface of Pluto and Eris (another dwarf planet) were obtained.
3. Ultraviolet auroras from Saturn, Jupiter and its moon Ganymede were captured.
4. Planets have been found outside the solar system, as well as a large number of protoplanetary disks around stars in the Orion Nebula. Evidence has been found that planet formation occurs in many stars in our galaxy.
5. Contributed to partial confirmation of the theory about the presence of supermassive black holes in the centers of galaxies.
6. Evidence has been obtained that the Universe is expanding at an accelerating rate, rather than at a constant (or decaying) rate.
7. The exact age of the Universe has been confirmed - 13.7 billion years.
8. The presence of analogues of gamma-ray bursts in the optical range was discovered.
9. Confirmation of the hypothesis about the isotropy (i.e. the sameness of the Universe itself and its properties in its individual parts) of the Universe.
10. The most distant parts of the Universe were photographed, right up to the time of formation of the first stars (i.e. Hubble allowed us to look into the past 12.7 - 13 billion years).

The merits of the telescope also include a huge number of impressive photographs of the sky and its individual objects, which, in addition to scientific value, also have aesthetic value. Below are the best images from Hubble's 23 years of operation. You can look at and admire these frames for hours.

Hubble Space Telescope

Typically, astronomers built their observatories on mountain tops, above the clouds and polluted atmosphere. But even then the image was distorted by air currents. The clearest image is available only from an extra-atmospheric observatory - space.

With a telescope you can see things that are inaccessible to the human eye because the telescope collects more electromagnetic radiation. Unlike a spyglass, which uses lenses to collect and focus light, large astronomical telescopes use mirrors to perform this function.

Telescopes with the largest mirrors should have the best images because they collect the most radiation.

The Hubble Space Telescope is an automatic observatory in orbit around the Earth, named after Edwin Hubble, an American astronomer.

And although Hubble's mirror is only 2.4 meters in diameter - smaller than the largest telescopes on Earth - it can see objects 100 times sharper and details ten times finer than the best ground-based telescopes. And this is because it is above the distorting atmosphere.

The Hubble Telescope is a joint project between NASA and the European Space Agency.

Placing a telescope in space makes it possible to detect electromagnetic radiation in ranges in which the earth’s atmosphere is opaque, primarily in the infrared range.

Due to the absence of atmospheric influence, the resolution of the telescope is 7-10 times greater than a similar telescope located on Earth.

Mars

The Hubble Space Telescope has helped scientists learn a lot about the structure of our galaxy, so it is very difficult to assess its importance for humanity.

One only needs to look at the list of the most important discoveries of this optical device to understand how useful it was, and what an important tool in space exploration it can still be.

Using the Hubble telescope, the collision of Jupiter with a comet was studied, an image of the relief of Pluto was obtained, data from the telescope became the basis for a hypothesis about the mass of black holes located at the center of absolutely every galaxy.

Scientists were able to see auroras on some planets of the solar system, such as Jupiter and Saturn, and many observations and discoveries were made.

Jupiter

The Hubble Space Telescope has peered into another solar system, 25 light-years away from ours, and captured images of several of its planets for the first time.

The Hubble telescope captured images of new planets

In one of the photographs taken in optical, that is, visible light, Hubble captured the planet Fomalhot orbiting the bright star Fomalhot, located 25 light years away from us (about 250 trillion kilometers) in the constellation Southern Pisces.

“The data from Hubble is incredibly important. The light emitted from the planet Fomalhot is a billion times weaker than the light emanating from the star,” commented on the image of the new planet, astronomer from the University of California Paul Kalas. He and other scientists began studying the star Fomalhot back in 2001, when the existence of a planet near the star was not yet known.

In 2004, Hubble sent back to Earth the first images of the regions around the star.

In new images from the Hubble Space Telescope, the astronomer received “documentary” confirmation of his assumptions about the existence of the planet Fomalhot.

Using photographs from the orbital telescope, scientists also “saw” three more planets in the constellation Pegasus.
In total, astronomers have discovered about 300 planets outside our solar system.

But all these discoveries were made on the basis of indirect evidence, mainly through observing the effects of their gravitational fields on the stars around which they orbit.

"Every planet outside our solar system was just a diagram," said Bruce McIntosh, an astrophysicist at the National Laboratory in California. "We've been trying to get pictures of planets for eight years without success, and now we have pictures of several planets at once."

Over 15 years of operation in low-Earth orbit, Hubble received 700 thousand images of 22 thousand celestial objects - stars, nebulae, galaxies, planets.

However, the price that has to be paid for Hubble's achievements is very high: the cost of maintaining a space telescope is 100 times or more higher than a ground-based reflector with a 4-meter mirror.

Already in the first weeks after the telescope began operation in 1990, the resulting images demonstrated a serious problem in the telescope's optical system. Although the image quality was better than that of ground-based telescopes, Hubble could not achieve the desired sharpness, and the resolution of the images was significantly worse than expected.
Image analysis showed that the source of the problem was the incorrect shape of the primary mirror. It was made too flat around the edges. The deviation from the specified surface shape was only 2 micrometers, but the result was catastrophic - an optical defect in which light reflected from the edges of the mirror is focused at a point different from the one at which light reflected from the center of the mirror is focused.
The loss of a significant portion of the light flux significantly reduced the telescope's suitability for observing dim objects and obtaining images with high contrast. This meant that almost all cosmological programs became simply impossible, since they required observations of particularly dim objects.

During the first three years of operation, before the installation of corrective devices, the telescope made a large number of observations. The defect did not have a major effect on the spectroscopic measurements. Despite experiments being canceled due to a defect, many important scientific results were achieved.

Telescope maintenance.

Maintenance of the Hubble telescope is performed by astronauts during spacewalks from reusable spacecraft such as the Space Shuttle.

A total of four expeditions were carried out to service the Hubble telescope.

Due to a defect in the mirror, the first expedition to service the telescope had to install corrective optics on the telescope. The expedition (December 2-13, 1993) was one of the most difficult; five long spacewalks were carried out. In addition, solar panels were replaced, the on-board computer system was updated, and the orbit was corrected.

The second maintenance was carried out on February 11-21, 1997. Research equipment was replaced, the flight recorder was replaced, thermal insulation was repaired, and orbit correction was performed.

Expedition 3A took place December 19-27, 1999. It was decided to carry out some of the work ahead of schedule. This was caused by three of the six guidance system gyros failing. The expedition replaced all six gyroscopes, the precision guidance sensor and the on-board computer.

Expedition 3B (fourth mission) was carried out on March 1-12, 2002. During the expedition, the dim object camera was replaced by an improved survey camera. The solar panels were replaced for the second time. The new panels were one-third smaller in area, which significantly reduced losses due to friction in the atmosphere, but at the same time generated 30% more energy, making simultaneous operation with all instruments installed on board the observatory possible.

The work carried out significantly expanded the capabilities of the telescope and made it possible to obtain images of deep space.

The Hubble telescope is expected to remain in orbit until at least 2013.

Most significant observations

*Hubble provided high-quality images of the 1994 collision of comet Shoemaker-Levy 9 with Jupiter.

* Maps of the surface of Pluto and Eris were obtained for the first time.

* Ultraviolet auroras were observed for the first time on Saturn, Jupiter and Ganymede.

* Additional data on planets outside the solar system, including spectrometric data, were obtained.

* A large number of protoplanetary disks have been found around stars in the Orion Nebula. It has been proven that the process of planet formation occurs in most stars of our Galaxy.

* The theory of supermassive black holes in the centers of galaxies has been partially confirmed; based on observations, a hypothesis has been put forward linking the mass of black holes and the properties of the galaxy.

* the age of the Universe has been updated to 13.7 billion years.