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 has seen Orbital Station"World". 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 the construction of Hubble is a constant overcoming of difficulties, the struggle for funding and the search for solutions in Unexpected 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. Scientific background 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, several successful launches were carried out and simpler devices were delivered into orbit, and in 1968 NASA gave green light Hubble's predecessor, the LST, the Large Space Telescope, with more large diameter mirrors - 3 meters versus Hubble's 2.4 - and the ambitious task of launching it already in 1972, using 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 are the optical system that Perkin-Elmer was working on, and the spacecraft that Lockheed was creating. 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 according to innovative technology until the end of 1981, greatly exceeding budget and damaging 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 received a contract to manufacture a spare mirror using traditional methods polishing if problems arise with polishing the main mirror. Delays in creating the remaining components slowed down the process so much that it became famous quote from NASA's characterization of work schedules that 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 null-corrector, which showed correct results and on 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 very wrong high accuracy. The distortion was known, and all that remained was to compensate for it, for which they developed special system COSTAR adjustments. 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. She gave up precious space in the telescope to the spectrograph and took pride of place in National Museum Aeronautics and Astronautics, after dismantling as part of the fourth Hubble servicing expedition 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 matrices, 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 part common square instead of quarter, but in 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 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
Your very own famous shot Hubble did the first of April 95, without being distracted from 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 interesting topic, that large stars in its center partially dispelled it, and even just from 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 on southern outskirts 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 the explosions Supernovas. And this picture clearly shows one of the scenarios future fate 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 already in itself interesting event, 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 took place: 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: an egg or a penguin.
A butterfly emerging from the remains of a star in 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.
Creates these wings 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's hard to understand the value of Hubble for a non-astronomer, but for us it's beautiful symbol achievements of mankind. Not problem-free, with complicated history, the telescope has become a successful project, which, hopefully, will continue to 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.
April 24, 1990 was launched into Earth orbit Hubble orbital telescope, who over almost a quarter of a century of his existence made many great discoveries that shed light on the Universe, its history and secrets. And today we will talk about this orbital observatory, which has become legendary in our time, its history, as well as about some important discoveries
made with its help.
History of creation
The idea of placing a telescope where nothing would interfere with its work appeared in the interwar years in the work of the German engineer Hermann Oberth, but the theoretical justification for this was put forward in 1946 by the American astrophysicist Leyman Spitzer. He was so captivated by the idea that he devoted himself to its implementation. most of his scientific career.The first orbital telescope was launched by Great Britain in 1962, and by the United States of America in 1966. The successes of these devices finally convinced the world scientific community of the need to build a large space observatory capable of looking even into the very depths of the Universe.
Work on the project that eventually became the Hubble Telescope began in 1970, but for a long time there was not enough funding to successful implementation ideas. There were periods when the American authorities suspended financial flows altogether.
The limbo ended in 1978, when the US Congress allocated $36 million for the creation of the orbital laboratory. At the same time, active work began on the design and construction of the facility, which involved many research centers and technology companies, a total of thirty-two institutions around the world.
Initially, it was planned to launch the telescope into orbit in 1983, then these dates were postponed to 1986. But the disaster of the Challenger space shuttle on January 28, 1986 forced us to once again revise the launch date of the object. As a result, Hubble launched into space on April 24, 1990 on the Discovery shuttle.
Edwin Hubble
Already in the early eighties, the projected telescope was named in honor of Edwin Powell Hubble, the great American astronomer who made a huge contribution to the development of our understanding of what the Universe is, as well as what astronomy and astrophysics of the future should be like.
It was Hubble who proved that there are other galaxies in the Universe besides the Milky Way, and also laid the foundation for the theory of the Expansion of the Universe.
Edwin Hubble died in 1953, but became one of the founders American school astronomy, its most famous representative and symbol. It is not for nothing that not only the telescope, but also the asteroid is named after this great scientist.
The most significant discoveries of the Hubble telescope
In the nineties of the twentieth century, the Hubble telescope became one of the most famous man-made objects mentioned in the press. Photographs taken by this orbital observatory were printed on the front pages and covers of not only scientific and popular science magazines, but also the regular press, including yellow newspapers.
The discoveries made with the help of Hubble significantly revolutionized and expanded the human understanding of the Universe and continue to do so to this day.
The telescope photographed and sent back to Earth more than a million high-resolution images, allowing one to peer into depths of the Universe that would otherwise be impossible to reach.
One of the first reasons for the media to start talking about the Hubble telescope was its photographs of comet Shoemaker-Levy 9, which collided with Jupiter in July 1994. About a year before the fall, while observing this object, the orbital observatory recorded its division into several dozen parts, which then fell over the course of a week onto the surface of the giant planet.
The size of Hubble (mirror diameter is 2.4 meters) allows it to conduct research in a wide variety of areas of astronomy and astrophysics. For example, it was used to take pictures of exoplanets (planets located beyond solar system), watch the agony of old stars and the birth of new ones, find mysterious black holes, explore the history of the Universe, and also check current scientific theories, confirming or refuting them.
Modernization
Despite the launch of other orbital telescopes, Hubble continues to be the main instrument of stargazers of our time, constantly supplying them with new information from the most remote corners of the Universe.However, over time, problems began to arise in the operation of Hubble. For example, already in the first week of operation of the telescope, it turned out that its main mirror had a defect that did not allow achieving the expected sharpness of the images. So we had to install an optical correction system on the object directly in orbit, consisting of two external mirrors.
To repair and modernize the Hubble orbital observatory, four expeditions were carried out to it, during which new equipment was installed on the telescope - cameras, mirrors, solar panels and other devices to improve the operation of the system and expand the scope of the observatory.
Future
After latest modernization, which occurred in 2009, it was decided that the Hubble telescope will remain in orbit until 2014, when it will be replaced by a new space observatory, the James Webb. But now it is already known that the operational life of the facility will be extended at least until 2018, or even 2020.There are three advantages of analogues: the image quality is not affected, due to less light scattering, located objects and the range of electromagnetic waves from infrared to ultraviolet. All these advantages are fully exploited thanks to the complex design of the Hubble telescope.
The telescope's primary mirror has a diameter of 2.4 m, and the secondary mirror has a diameter of 0.34 m. The distance between them is strictly verified and amounts to 4.9 m. The optical system allows collecting light into a beam with a diameter of 0.05 inches (even at the most best telescopes on Earth the circle of dispersion is greater than 0.5 inches). The resolution of the Hubble telescope is 7-10 times greater than that of its analogues on Earth.
With such exposure it is very necessary high degree stabilization and pointing accuracy. This was the main difficulty in the design - as a result, a complex combination of sensors, gyroscopes and star guides allows you to maintain focus within 0.007 inches for a long time (the pointing accuracy is at least 0.01 inches).
There are six main ones installed on board scientific instruments, which are achievements scientific thought at the time of shuttle launch. These are a high Goddard for working in the ultraviolet range, a camera and spectrograph for shooting dim objects, a planetary and wide-angle camera, a high-speed photometer for observing objects with varying brightness, and precision pointing sensors.
To ensure that the system is self-sufficient and does not require power sources, it is equipped with powerful solar panels, which, in turn, charge six hydrogen-nickel batteries. All computers, batteries, telemetry and other systems are located so that they can be easily replaced if necessary.
Video on the topic
Optical instruments have been known since ancient times. Archimedes used lenses to focus light and destroy enemy wooden ships. But telescopes appeared much later, and the reason for this is unknown.
Origins
The system of teachings about optics was created by the Greek scientists Euclid and Aristotle. In essence, optics is the result of studying the structure of the human eye, and the underdevelopment of anatomy in antiquity did not allow the development of optics into a serious science.In the 13th century, the first glasses appeared based on knowledge of rectilinear rays. They served utilitarian purposes - they helped craftsmen examine small details. It is unlikely that this invention was the result of long research - it could have been pure luck, the discovery that ground glass can have the effect of enlarging an object when approaching the eye.
The English naturalist Bacon wrote about Arab instruments that could, in theory, give magnification so that stars could be seen on close range. Da Vinci's genius reached such heights that he designed his own glass machines and wrote treatises on photometry. The single-lens telescope, or more precisely, its drawings and technical documentation, was thought out to the smallest detail by Leonardo, and the genius himself claimed that a magnification of 50 times could be achieved in this way. It is unlikely that such a construction had the right to life, but the fact is a fact - the first stone in the foundation of a new direction in science was laid.
The first spotting scope was made in Holland in late XVI - early XVII century (opinions about the exact date today differ) by Z. Jansen in Middelburg in the likeness of a certain Italian telescope. This event was officially documented. The Dutch showed considerable skill in the production of spotting scopes. Metzius, Lippershey - their names were preserved in the chronicles, and their products were presented to the court of dukes and kings, for which the craftsmen were rewarded with large sums of money. Who was the first is still unknown to this day. Tools were made from cheap materials, but on a practical, rather than theoretical basis, as was previously the case.
Galileo Galilei received a professorship at the University of Padua for presenting his prototype telescope to the Doge of Venice. Its authorship leaves no doubt, since the products are still kept in Florentine museums. His telescopes made it possible to achieve a magnification of 30 times, while other masters made telescopes with a magnification of 3 times. He also contributed a practical basis to the doctrine of the heliocentric essence of the solar system, personally observing the planets and stars.
The great astronomer Johannes Kepler, having familiarized himself with Galileo’s invention, compiled a detailed
Since the very beginning of astronomy, since the time of Galileo, astronomers have been pursuing one common goal: see more, see further, see deeper. And the Hubble Space Telescope, launched in 1990, is a huge step in this direction. The telescope is in Earth orbit above the atmosphere, which could distort and block radiation coming from space objects. Thanks to its absence, astronomers receive images of the highest quality using Hubble. It is almost impossible to overestimate the role that the telescope played for the development of astronomy - Hubble is one of the most successful and long-term projects of the NASA space agency. He sent hundreds of thousands of photographs to Earth, shedding light on many of the mysteries of astronomy. He helped determine the age of the Universe, identify quasars, prove that massive black holes are located at the center of galaxies, and even conduct experiments to detect dark matter.
The discoveries changed the way astronomers looked at the Universe. The ability to see in great detail has helped transform some astronomical hypotheses into facts. Many theories were discarded in order to go in one right direction. Among Hubble's achievements, one of the main ones is the determination age of the universe, which today scientists estimate at 13 - 14 billion years. This is undoubtedly more accurate than previous data of 10 - 20 billion years. Hubble also played a key role in the discovery of dark energy, the mysterious force that is causing the universe to expand at an ever-increasing rate. Thanks to Hubble, astronomers were able to see galaxies at all stages of their development, starting from the formation that took place in the young Universe, which helped scientists understand how their birth occurred. Using the telescope, protoplanetary disks, accumulations of gas and dust around young stars were found, around which new ones will soon (by astronomical standards, of course) appear planetary systems. He was able to find the sources of gamma-ray bursts - strange, incredibly powerful bursts of energy - in distant galaxies during the collapse of supermassive stars. And this is only part of the discoveries of a unique astronomical instrument, but they already prove that the $2.5 billion spent on the creation, launch into orbit and maintenance is the most profitable investment on the scale of all mankind.
Hubble Space Telescope
Hubble has amazing performance. The entire astronomical community benefits from his ability to see into the depths of the Universe. Each astronomer can send a request to certain time use its services, and a group of specialists decides whether this can be done. After an observation, it usually takes a year before the astronomical community receives the results of the research. Since the data obtained using the telescope is available to everyone, any astronomer can conduct his research by coordinating the data with observatories around the world. This policy makes research open and therefore more effective. However, the unique capabilities of the telescope also mean the highest level of demand for it - astronomers around the world are fighting for the right to use Hubble’s services in their free time from main missions. Every year, more than a thousand applications are received, among which the best according to experts are selected, but according to statistics, only 200 are satisfied - only a fifth of the total number of applicants conduct their research using Hubble.
Why was it necessary to launch the telescope into near-Earth space, and why is the device in such high demand among astronomers? The fact is that the Hubble telescope was able to solve two problems of ground-based telescopes at once. First, signal blur earth's atmosphere limits the capabilities of ground-based telescopes, regardless of their technical excellence. Atmospheric blur allows us to see stars twinkling when we look at the sky. Secondly, the atmosphere absorbs radiation with a certain wavelength, most strongly ultraviolet, x-ray and gamma radiation. And this serious problem, since the study of space objects is more effective the larger the energy range taken.
And it is precisely in order to avoid the negative influence of the atmosphere on the quality of the resulting images that the telescope is located above it, at a distance of 569 kilometers above the surface. At the same time, the telescope makes one revolution around the Earth in 97 minutes, moving at a speed of 8 kilometers per second.
Hubble telescope optical system
The Hubble telescope is a Ritchie-Chrétien system, or an improved version of the Cassegrain system, in which light initially hits a primary mirror, is reflected, and hits a secondary mirror, which focuses the light and directs it into the telescope's science instrument system through a small hole in the primary mirror. People often mistakenly believe that a telescope magnifies the image. In fact, he only collects maximum amount light from the object. Accordingly, the larger the main mirror, the more light it will collect and the clearer the image will be. The second mirror only focuses the radiation. The diameter of Hubble's primary mirror is 2.4 meters. It seems small, considering that the diameter of the mirrors of ground-based telescopes reaches 10 meters or more, but the absence of an atmosphere is still a huge advantage of the comic version.
To monitor space objects The telescope has a number of scientific instruments, working together or separately. Each of them is unique in its own way.
Advanced Camera for Surveys (ACS). The newest visible observing instrument designed for research into the early Universe, installed in 2002. This camera helped map the distribution of black matter, detect the most distant objects and study the evolution of galaxy clusters.
Near Infrared Camera and Multi-Object Spectrometer (NICMOS). Infrared sensor, detects heat when objects are hidden interstellar dust or gas, as, for example, in regions of active star formation.
Near-infrared camera and multi-object spectrometer (Space Telescope Imaging Spectrograph - STIS). Acts like a prism, decomposing light. From the resulting spectrum one can obtain information about the temperature, chemical composition, density and movement of the objects under study. STIS ceased operation on August 3, 2004 due to technical problems, but the telescope will be refurbished during a scheduled maintenance in 2008.
Wide Field and Planetary Camera 2 (WFPC2). A universal tool with which most of the photographs known to everyone were taken. Thanks to 48 filters, it allows you to see objects in a fairly wide range of wavelengths.
Fine Guidance Sensors (FGS). They are not only responsible for the control and orientation of the telescope in space - they orient the telescope in relation to the stars and do not allow it to stray from the course, but they also make precision measurements of the distances between stars and record relative movement.
As with many spacecraft in Earth orbit, the Hubble Telescope's power source is solar radiation, fixed by two twelve-meter solar panels, and accumulated for uninterrupted operation while passing through shadow side Earth. The design of the guidance system to the desired target - an object in the Universe - is also very interesting - after all, successfully photographing a distant galaxy or quasar at a speed of 8 kilometers per second is very difficult task. The telescope's orientation system includes the following components: the already mentioned precision guidance sensors, which mark the position of the apparatus relative to the two “leading” stars; Position sensors relative to the Sun are not only auxiliary tools for orienting the telescope, but also necessary tools to determine the need to close/open the aperture door to prevent the equipment from “burning out” when it is exposed to focused sunlight; magnetic sensors that orient the spacecraft relative to magnetic field Earth; a system of gyroscopes that track the movement of the telescope; and an electro-optical detector that monitors the position of the telescope relative to the selected star. All this provides not only the ability to control the telescope and “aim” at the desired space object, but also prevents the breakdown of valuable equipment that cannot be quickly replaced with a functional one.
However, Hubble's work would be meaningless without the ability to transfer the data obtained for study in laboratories on earth. And to solve this problem, four antennas were installed on Hubble, which exchange information with the Flight Operations Team at the Goddard Space Flight Center in Greenbelt. Satellites located in Earth orbit are used to communicate with the telescope and set coordinates; they are also responsible for relaying data. Hubble has two computers and several less complex subsystems. One of the computers controls the navigation of the telescope, all other systems are responsible for the operation of instruments and communication with satellites.
Scheme for transmitting information from orbit to earth
Data from ground research group arrive at the Goddard Space Flight Center, then to Research institute Space Telescope Science Institute, where a group of specialists process data and record it on magneto-optical media. Every week, the telescope sends back to Earth enough information to fill more than twenty DVDs, and access to this huge amount of valuable information is open to everyone. The bulk of the data is stored in the digital FITS format, which is very convenient for analysis, but extremely unsuitable for publication in the media. That is why the most interesting images for the general public are published in the more common image formats - TIFF and JPEG. Thus, the Hubble telescope has become not just a unique scientific instrument, but also one of the few opportunities for anyone to look at the beauty of the Cosmos - a professional, an amateur, and even a person unfamiliar with astronomy. To some regret, we have to say that access to the telescope for amateur astronomers is now closed due to a decrease in project funding.
Orbital telescope Hubble
The Hubble Telescope's past is no less interesting than its present. For the first time the idea of creating similar installation originated back in 1923 with Hermann Oberth, founder rocket technology Germany. It was he who first said about the possibility of delivering a telescope to about earth's orbit using a rocket, although even the rockets themselves did not yet exist. This idea was developed in 1946 in his publications on the need to create a space observatory by the American astrophysicist Lyman Spitzer. He predicted the possibility of receiving unique photos, which are simply impossible to do in ground conditions. Over the next fifty years, the astrophysicist actively promoted this idea until the beginning of its real application.
Spitzer was a leader in the development of several orbital observatory projects, including the Copernicus satellite and the Orbiting Astronomical Observatory. Thanks to him, the Large Space Telescope project was approved in 1969; unfortunately, due to lack of funding, the dimensions and equipment of the telescope were somewhat reduced, including the size of the mirrors and the number of instruments.
In 1974, it was proposed to make interchangeable instruments with a resolution of 0.1 arcsecond and operating wavelengths from ultraviolet to visible and infrared. The shuttle was supposed to deliver the telescope into orbit and return it to Earth for maintenance and repairs that were also possible in space.
In 1975, NASA and the European Space Agency (ESA) began work on the Hubble Telescope. In 1977, Congress approved funding for the telescope.
After this decision, a list of scientific instruments for the telescope began to be compiled, and five winners of the competition for the creation of equipment were selected. There was a huge amount of work ahead. They decided to name the telescope in honor of the astronomer who showed that the small “scraps” visible through the telescope are distant galaxies and proved that the Universe is expanding.
After various delays, the launch was scheduled for October 1986, but on January 28, 1986, the space shuttle Challenger exploded one minute after liftoff. The testing of the shuttles continued for more than two years, which means that the launch of the Hubble telescope into orbit was postponed by four years. During this time, the telescope was improved, and on April 24, 1990, the unique device rose into its orbit.
Launch of the shuttle with the Hubble telescope on board
In December 1993, the space shuttle Endeavor, with a crew of seven, was carried into orbit to perform maintenance on the telescope. Two cameras were replaced, as well as solar panels. In 1994, the first photographs were taken from the telescope, the quality of which shocked astronomers. Hubble has completely justified itself.
Maintenance, modernization and replacement of cameras, solar panels, inspection of thermal insulation cladding, as well as Maintenance were held three more times: in 1997, 1999 and 2002.
Hubble telescope upgrade, 2002
The next flight was supposed to take place in 2006, but on February 1, 2003, due to problems with the skin, the space shuttle Columbia burned up in the atmosphere during its return. As a result, there is a need to conduct additional studies the possibility of further use of the Shuttles, which ended only on October 31, 2006. This is what led to the postponement of the next scheduled maintenance of the telescope to September 2008.
Today the telescope operates normally, transmitting 120 GB of information weekly. Hubble's successor, the Webb Space Telescope, is also being developed, which will explore high-redshift objects in the early Universe. It will be at an altitude of 1.5 million kilometers, launch is scheduled for 2013.
Of course, Hubble does not last forever. The next repair is scheduled for 2008, but still the telescope is gradually wearing out and becoming inoperable. This will happen around 2013. When this happens, the telescope will remain in orbit until it degrades. Then, in a spiral, Hubble will begin to fall to Earth, and will either follow the Mir station, or will be safely delivered to Earth and become a museum exhibit with a unique history. But still, the legacy of the Hubble telescope: its discoveries, its example of almost flawless work and photographs known to everyone - will remain. We can be sure that his achievements will continue to help in unlocking the mysteries of the Universe for a long time to come, as a triumph of the amazingly rich life of the Hubble telescope.
At the end of September 2008 at the telescope named after. The Hubble unit responsible for transmitting information to Earth failed. The telescope repair mission was rescheduled for February 2009.
Technical characteristics of the telescope named after. Hubble:
Launch: April 24, 1990 12:33 UT
Dimensions: 13.1 x 4.3 m
Weight: 11,110 kg
Optical design: Ritchie-Chretien
Vignetting: 14%
Field of view: 18" (for scientific purposes), 28" (for guiding)
Angular resolution: 0.1" at 632.8 nm
Spectral range: 115 nm - 1 mm
Stabilization accuracy: 0.007" in 24 hours
Design orbit of the spacecraft: altitude - 693 km, inclination - 28.5°
Orbital period around Zesli: between 96 and 97 minutes
Planned operating time: 20 years (with maintenance)
Cost of the telescope and spacecraft: $1.5 billion (in 1989 dollars)
Main mirror: Diameter 2400 mm; Radius of curvature 11,040 mm; Eccentricity square 1.0022985
Secondary mirror: Diameter 310 mm; Radius of curvature 1.358 mm; Squared eccentricity 1.49686
Distances: Between mirror centers 4906.071 mm; From secondary mirror to focus 6406.200 mm
What is Hubble?
American scientist Edwin Powell Hubble became widely known for his discovery of the expansion of the Universe. Great scientists still often mention him in their articles. Hubble is the man after whom the radio telescope was named, and thanks to whom all associations and stereotypes were completely replaced.
The Hubble telescope is one of the most famous among objects that are directly related to space. It can be confidently considered a real automatic orbital observatory. This space giant required a considerable financial investment (after all, the costs of an unearthly telescope were hundreds of times higher than the cost of a ground-based one), as well as resources and time. Based on this, the two largest agencies in the world, such as NASA and the European Space Agency (ESA), decided to combine their capabilities and make a joint project.
What year it was launched is no longer known classified information. The launch into earth orbit took place on April 24, 1990 on board the Discovery shuttle STS-31. Returning to history, it is worth mentioning that the launch year was originally planned to be different. The expected date was supposed to be October 1986, but in January of the same year, The Challenger disaster occurred and everyone was forced to postpone the planned launch. With each month of downtime, the cost of the program increased by 6 million dollars. After all, it is not so easy to keep an object in perfect condition that will need to be sent into space. Hubble was placed in a special room , in which an artificially purified atmosphere was created, and the on-board systems were partially functioning.During storage, some devices were also replaced with more modern ones.
When Hubble was launched, everyone expected an incredible triumph, but not everything immediately turned out the way they wanted. Scientists encountered problems from the very first images. It was clear that there was a defect in the telescope mirror, and the quality of the images was different from what was expected. It was also not entirely clear how much years will pass from the moment the problem is discovered until it is resolved. After all, it was obvious that it was impossible to replace the main mirror of the telescope directly in orbit, and returning it to Earth was extremely expensive, so it was decided that it was necessary to install additional equipment on it and use it to compensate for the mirror defect. So, already in December 1993 The shuttle Endeavor was sent with the necessary structures. The astronauts went into outer space five times and successfully installed the necessary parts on the Hubble telescope.
What new did the telescope see in space? And what discoveries has humanity been able to make based on the photographs? These are some of the most common questions scientists ever ask. Of course, the biggest stars taken by telescope did not go unnoticed. Namely, thanks to the uniqueness of the telescope, astronomers simultaneously identified nine huge stars (in star cluster R136), whose mass is more than 100 times the mass of the Sun. Stars have also been discovered whose mass exceeds the mass of the Sun by 50 times.
Also notable was the photo of two hundred insanely hot stars that together give us the nebula NGC 604. It was Hubble that was able to capture the fluorescence of the nebula, which was caused by ionized hydrogen.
Speaking of theory big bang, which today is one of the most widely discussed and most reliable in the history of the origin of the Universe, it is worth remembering the cosmic microwave background radiation. CMB radiation is one of its fundamental evidence. But another one was the cosmological redshift. Taken together, the result was a manifestation of the Doppler effect. According to it, the body sees objects that approach it in blue, and if they move away, they become redder. Thus, observing space objects from the Hubble telescope, the shift was red and on this basis a conclusion was made about the expansion of the Universe.
When looking at telescope images, one of the first things you will see is the Far Field. In the photo you will no longer be able to see the stars individually - they will be entire galaxies. And the question immediately arises: at what distance can the telescope see and what is its extreme limit? In order to answer how the telescope sees so far, we need to take a closer look at the Hubble design.
Telescope Specifications
- Overall dimensions of the entire satellite: 13.3 m - length, weight about 11 tons, but taking into account all installed instruments, its weight reaches 12.5 tons and diameter - 4.3 m.
- The shape of the orientation accuracy can reach 0.007 arcseconds.
- Two bifacial solar panels are 5 kW, but there are 6 more batteries that have a capacity of 60 amp hours.
- All engines run on hydrazine.
- An antenna that is capable of receiving all data at a speed of 1 kB/s and transmitting at 256/512 kB/s.
- The main mirror, the diameter of which is 2.4 m, as well as the auxiliary one - 0.3 m. The material of the main mirror is fused quartz glass, which is not susceptible to thermal deformation.
- What is the magnification, so is the focal length, namely 56.6 m.
- The frequency of circulation is once every hour and a half.
- The radius of the Hubble sphere is the ratio of the speed of light to the Hubble constant.
- Radiation characteristics - 1050-8000 angstroms.
- But at what height above the Earth’s surface the satellite is located has long been known. This is 560 km.
How does the Hubble telescope work?
The operating principle of the telescope is a reflector of the Ritchie-Chretien system. The structure of the system is the main mirror, which is concave hyperbolically, but its auxiliary mirror is convex hyperbolic. The device installed at the very center of the hyperbolic mirror is called an eyepiece. Field of view is about 4°.
So who actually took part in the creation of this amazing telescope, which, despite its venerable age, continues to delight us with its discoveries?
The history of its creation goes back to the distant seventies of the 20th century. Several companies worked on the most important parts of the telescope, namely the main mirror. After all, the requirements were quite strict, and the result was planned to be ideal. Thus, PerkinElmer wanted to use its machines with new technologies to achieve the desired shape. But Kodak signed a contract that involved using more traditional methods, but for spare parts. Manufacturing work began back in 1979, and polishing of the necessary parts continued until mid-1981. The dates were greatly shifted, and questions arose about the competence of the PerkinElmer company; as a result, the launch of the telescope was postponed to October 1984. Soon, incompetence became increasingly evident, and the launch date was pushed back several more times. History confirms that one of the proposed dates was September 1986, while total budget the entire project grew to 1.175 billion dollars.
And finally, information about the most interesting and significant observations Hubble telescope:
- Planets have been discovered that are outside the solar system.
- A huge number of protoplanetary disks have been found that are located around the stars of the Orion Nebula.
- There has been a discovery in the study of the surface of Pluto and Eris. The first cards were received.
- Of no small importance is the partial confirmation of the theory about very massive black holes that are located in the centers of galaxies.
- It has been shown that they are quite similar in shape Milky Way and the Andromeda Nebula have significant differences in their history of origin.
- The exact age of our Universe has been unambiguously established. It is 13.7 billion years old.
- Hypotheses regarding isotropy are also correct.
- In 1998, studies and observations from ground-based telescopes and Hubble were combined, and it was found that dark energy contains ¾ of the total energy density of the Universe.
Studying outer space continues...