91-448: The KBC Void (or Local Hole ) is an immense, comparatively empty region of space, named after astronomers Ryan Keenan, Amy Barger , and Lennox Cowie , who studied it in 2013. The existence of a local underdensity has been the subject of many pieces of literature and research articles. The underdensity is proposed to be roughly spherical, approximately 2 billion light-years (600 megaparsecs , Mpc) in diameter. As with other voids , it
182-562: A spectral resolution of 90,000. Also optimized for ultraviolet observations were the FOC and FOS, which were capable of the highest spatial resolution of any instruments on Hubble. Rather than CCDs, these three instruments used photon -counting digicons as their detectors. The FOC was constructed by ESA, while the University of California, San Diego , and Martin Marietta Corporation built
273-471: A "sop" to the astronomy community. "There's something in there, so all is well". I figured in my own little head that to get that community energized we'd be better off zeroing it out. Then they would say, "Whoa, we're in deep trouble", and it would marshal the troops. So I advocated that we not put anything in. I don't remember any of the detailed discussions or whether there were any, but Jim went along with that so we zeroed it out. It had, from my perspective,
364-494: A costly program had a lengthy working life, and the concurrent development of plans for the reusable Space Shuttle indicated that the technology to allow this was soon to become available. The continuing success of the OAO program encouraged increasingly strong consensus within the astronomical community that the LST should be a major goal. In 1970, NASA established two committees, one to plan
455-419: A different point from the light reflecting off its center. The effect of the mirror flaw on scientific observations depended on the particular observation—the core of the aberrated PSF was sharp enough to permit high-resolution observations of bright objects, and spectroscopy of point sources was affected only through a sensitivity loss. However, the loss of light to the large, out-of-focus halo severely reduced
546-437: A final sharp focus and the best image quality obtained was drastically lower than expected. Images of point sources spread out over a radius of more than one arcsecond, instead of having a point spread function (PSF) concentrated within a circle 0.1 arcseconds (485 n rad ) in diameter, as had been specified in the design criteria. Analysis of the flawed images revealed that the primary mirror had been polished to
637-558: A mass between 10 million and 100 million times that of the Sun continue to accumulate matter and grow slowly in comparison. The researchers found that one or more systems connect a galaxy's formation of stars to its loss of cosmic materials through its black hole because the processes occur simultaneously. Barger and her team refer to the apparent shift in star formation from massive galaxies to relatively lightweight ones as ' cosmic downsizing' and as this phenomenon continues, dwarf galaxies will be
728-528: A nitrogen gas purge was performed before launching the telescope into space. As well as electrical power systems, the Pointing Control System controls HST orientation using five types of sensors (magnetic sensors, optical sensors, and six gyroscopes) and two types of actuators ( reaction wheels and magnetic torquers ). While construction of the spacecraft in which the telescope and instruments would be housed proceeded somewhat more smoothly than
819-546: A possibly failure-prone battery, and make other improvements. Furthermore, the ground software needed to control Hubble was not ready in 1986, and was barely ready by the 1990 launch. Following the resumption of shuttle flights, Space Shuttle Discovery successfully launched the Hubble on April 24, 1990, as part of the STS-31 mission. At launch, NASA had spent approximately US$ 4.7 billion in inflation-adjusted 2010 dollars on
910-585: A postdoctoral fellowship from the University of Hawaii Institute for Astronomy. During this time, she was a part of the MORPHS collaboration , a research group that studied the formation and morphologies of distant galaxies. Based on the data they retrieved from Hubble Space Telescope Wide Field and Planetary Camera 2 images, photometry and spectroscopy , the group was able to analyze and catalogue approximately 2,000 distant galaxies in 10 clusters and conclude that
1001-457: A reflective coating of 65 nm-thick aluminum and a protective coating of 25 nm-thick magnesium fluoride . Doubts continued to be expressed about Perkin-Elmer's competence on a project of this importance, as their budget and timescale for producing the rest of the OTA continued to inflate. In response to a schedule described as "unsettled and changing daily", NASA postponed the launch date of
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#17330845170301092-514: A report emphasizing the need for a space telescope, and eventually, the Senate agreed to half the budget that had originally been approved by Congress. The funding issues led to a reduction in the scale of the project, with the proposed mirror diameter reduced from 3 m to 2.4 m, both to cut costs and to allow a more compact and effective configuration for the telescope hardware. A proposed precursor 1.5 m (4 ft 11 in) space telescope to test
1183-551: A resolution of 0.64 megapixels. The wide field camera (WFC) covered a large angular field at the expense of resolution, while the planetary camera (PC) took images at a longer effective focal length than the WF chips, giving it a greater magnification. The Goddard High Resolution Spectrograph (GHRS) was a spectrograph designed to operate in the ultraviolet. It was built by the Goddard Space Flight Center and could achieve
1274-692: A sample of galaxies and found that Earth's galaxy, the Milky Way , is inside of a large void named the KBC Void for the research team. As of 2017, the KBC Void is the largest-known void with a diameter of approximately 2 billion light-years. In that same year, Barger's former student Benjamin Hoscheit presented the results of their follow-up study, in which Hoscheit used the linear kinematic Sunyaev-Zel'dovich (kSZ) effect to measure galaxy clusters' motions and confirm
1365-573: A telescope could be propelled into Earth orbit by a rocket. The history of the Hubble Space Telescope can be traced to 1946, to astronomer Lyman Spitzer 's paper "Astronomical advantages of an extraterrestrial observatory". In it, he discussed the two main advantages that a space-based observatory would have over ground-based telescopes. First, the angular resolution (the smallest separation at which objects can be clearly distinguished) would be limited only by diffraction , rather than by
1456-527: A vital research tool and as a public relations boon for astronomy . The Hubble telescope is named after astronomer Edwin Hubble and is one of NASA's Great Observatories . The Space Telescope Science Institute (STScI) selects Hubble's targets and processes the resulting data, while the Goddard Space Flight Center (GSFC) controls the spacecraft. Hubble features a 2.4 m (7 ft 10 in) mirror, and its five main instruments observe in
1547-406: A way that is not accurately predictable. The density of the upper atmosphere varies according to many factors, and this means Hubble's predicted position for six weeks' time could be in error by up to 4,000 km (2,500 mi). Observation schedules are typically finalized only a few days in advance, as a longer lead time would mean there was a chance the target would be unobservable by the time it
1638-485: A wide field of view, with the disadvantage that the mirrors have shapes that are hard to fabricate and test. The mirror and optical systems of the telescope determine the final performance, and they were designed to exacting specifications. Optical telescopes typically have mirrors polished to an accuracy of about a tenth of the wavelength of visible light , but the Space Telescope was to be used for observations from
1729-476: Is considered a pioneer in combining data from multiple telescopes to monitor multiple wavelengths and in discovering distant galaxies and supermassive black holes , which are outside of the visible spectrum . Barger is an active member of the International Astronomical Union . Barger earned a Bachelor of Arts in astronomy-physics in 1993 from the University of Wisconsin-Madison. She
1820-573: Is not completely empty; it contains the Milky Way , the Local Group , and the larger part of the Laniakea Supercluster . The Milky Way is within a few hundred million light-years of the void's center. It is debated whether the existence of the KBC void is consistent with the ΛCDM model . While Haslbauer et al. say that voids as large as the KBC void are inconsistent with ΛCDM, Sahlén et al. argue that
1911-813: Is physically located in Baltimore , Maryland on the Homewood campus of Johns Hopkins University , one of the 39 U.S. universities and seven international affiliates that make up the AURA consortium. STScI was established in 1981 after something of a power struggle between NASA and the scientific community at large. NASA had wanted to keep this function in-house, but scientists wanted it to be based in an academic establishment. The Space Telescope European Coordinating Facility (ST-ECF), established at Garching bei München near Munich in 1984, provided similar support for European astronomers until 2011, when these activities were moved to
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#17330845170302002-574: The Challenger disaster brought the U.S. space program to a halt, grounded the Shuttle fleet, and forced the launch to be postponed for several years. During this delay the telescope was kept in a clean room, powered up and purged with nitrogen, until a launch could be rescheduled. This costly situation (about US$ 6 million per month) pushed the overall costs of the project higher. However, this delay allowed time for engineers to perform extensive tests, swap out
2093-619: The Columbia disaster (2003), but after NASA administrator Michael D. Griffin approved it, the servicing mission was completed in 2009. Hubble completed 30 years of operation in April 2020 and is predicted to last until 2030 to 2040. Hubble is the visible light telescope in NASA's Great Observatories program ; other parts of the spectrum are covered by the Compton Gamma Ray Observatory ,
2184-885: The Chandra X-ray Observatory , and the Spitzer Space Telescope (which covers the infrared bands). The mid-IR-to-visible band successor to the Hubble telescope is the James Webb Space Telescope (JWST), which was launched on December 25, 2021, with the Nancy Grace Roman Space Telescope due to follow in 2027. In 1923, Hermann Oberth —considered a father of modern rocketry, along with Robert H. Goddard and Konstantin Tsiolkovsky —published Die Rakete zu den Planetenräumen ("The Rocket into Planetary Space"), which mentioned how
2275-546: The Hubble Deep Field and images of the Lockman Hole , the researchers were able to accurately count the number of black holes that exist in between those that are the closest and farthest away from Earth. The team discovered that the earliest black holes, which are a part of the early Universe and have at least 100 million times the mass of the Sun, quickly reach a size limit and stop accumulating matter. The black holes with
2366-670: The Next Generation Space Telescope and Constellation-X , were required to gain more insight into the two types of far-distant objects they observed. As a follow-up to the research presented in January, Barger lead a team in surveying black holes. The team used a Keck 10-meter telescope , James Clerk Maxwell Telescope and the Very Large Array of the National Radio Astronomy Observatory to study
2457-410: The atmosphere of Earth . Spitzer devoted much of his career to pushing for the development of a space telescope. In 1962, a report by the U.S. National Academy of Sciences recommended development of a space telescope as part of the space program , and in 1965, Spitzer was appointed as head of a committee given the task of defining scientific objectives for a large space telescope. Also crucial
2548-429: The cosmic microwave background and baryon acoustic oscillation data (67–68 km/s/Mpc). Other work has found no evidence for this in observations, finding the scale of the claimed underdensity to be incompatible with observations which extend beyond its radius. Important deficiencies were subsequently pointed out in this analysis, leaving open the possibility that the Hubble tension is indeed caused by outflow from
2639-453: The optical telescope assembly (OTA) and Fine Guidance Sensors for the space telescope. Lockheed was commissioned to construct and integrate the spacecraft in which the telescope would be housed. Optically, the HST is a Cassegrain reflector of Ritchey–Chrétien design , as are most large professional telescopes. This design, with two hyperbolic mirrors, is known for good imaging performance over
2730-468: The ultraviolet , visible , and near-infrared regions of the electromagnetic spectrum . Hubble's orbit outside the distortion of Earth's atmosphere allows it to capture extremely high-resolution images with substantially lower background light than ground-based telescopes. It has recorded some of the most detailed visible light images, allowing a deep view into space. Many Hubble observations have led to breakthroughs in astrophysics , such as determining
2821-465: The 1991 comedy The Naked Gun 2½: The Smell of Fear , in a scene where historical disasters are displayed, Hubble is pictured with RMS Titanic and LZ 129 Hindenburg . Nonetheless, during the first three years of the Hubble mission, before the optical corrections, the telescope carried out a large number of productive observations of less demanding targets. The error was well characterized and stable, enabling astronomers to partially compensate for
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2912-560: The DF-224 was added during Servicing Mission 1 in 1993, which consisted of two redundant strings of an Intel-based 80386 processor with an 80387 math co-processor. The DF-224 and its 386 co-processor were replaced by a 25 MHz Intel-based 80486 processor system during Servicing Mission 3A in 1999. The new computer is 20 times faster, with six times more memory, than the DF-224 it replaced. It increases throughput by moving some computing tasks from
3003-666: The European Space Astronomy Centre. One complex task that falls to STScI is scheduling observations for the telescope. Hubble is in a low-Earth orbit to enable servicing missions, which results in most astronomical targets being occulted by the Earth for slightly less than half of each orbit. Observations cannot take place when the telescope passes through the South Atlantic Anomaly due to elevated radiation levels, and there are also sizable exclusion zones around
3094-578: The FOS. The final instrument was the HSP, designed and built at the University of Wisconsin–Madison . It was optimized for visible and ultraviolet light observations of variable stars and other astronomical objects varying in brightness. It could take up to 100,000 measurements per second with a photometric accuracy of about 2% or better. HST's guidance system can also be used as a scientific instrument. Its three Fine Guidance Sensors (FGS) are primarily used to keep
3185-597: The Faint Object Spectrograph (FOS). WF/PC used a radial instrument bay, and the other four instruments were each installed in an axial instrument bay. WF/PC was a high-resolution imaging device primarily intended for optical observations. It was built by NASA's Jet Propulsion Laboratory , and incorporated a set of 48 filters isolating spectral lines of particular astrophysical interest. The instrument contained eight charge-coupled device (CCD) chips divided between two cameras, each using four CCDs. Each CCD has
3276-429: The KBC void, albeit in the context of MOND gravity rather than general relativity . It was later discovered that this outflow model successfully predicted the bulk flow curve, an important measure of the velocity field in the local Universe. Amy Barger Amy J. Barger (born January 18, 1971) is an American astronomer and Henrietta Leavitt Professor of Astronomy at the University of Wisconsin–Madison . She
3367-425: The Shuttle servicing missions. COSTAR was a corrective optics device rather than a science instrument, but occupied one of the four axial instrument bays. Since the final servicing mission in 2009, the four active instruments have been ACS, COS, STIS and WFC3. NICMOS is kept in hibernation, but may be revived if WFC3 were to fail in the future. Of the former instruments, three (COSTAR, FOS and WFPC2) are displayed in
3458-700: The Smithsonian National Air and Space Museum . The FOC is in the Dornier museum, Germany. The HSP is in the Space Place at the University of Wisconsin–Madison . The first WFPC was dismantled, and some components were then re-used in WFC3. Within weeks of the launch of the telescope, the returned images indicated a serious problem with the optical system. Although the first images appeared to be sharper than those of ground-based telescopes, Hubble failed to achieve
3549-518: The Sun (precluding observations of Mercury ), Moon and Earth. The solar avoidance angle is about 50°, to keep sunlight from illuminating any part of the OTA. Earth and Moon avoidance keeps bright light out of the FGSs, and keeps scattered light from entering the instruments. If the FGSs are turned off, the Moon and Earth can be observed. Earth observations were used very early in the program to generate flat-fields for
3640-738: The WFPC1 instrument. There is a so-called continuous viewing zone (CVZ), within roughly 24° of Hubble's orbital poles , in which targets are not occulted for long periods. Due to the precession of the orbit, the location of the CVZ moves slowly over a period of eight weeks. Because the limb of the Earth is always within about 30° of regions within the CVZ, the brightness of scattered earthshine may be elevated for long periods during CVZ observations. Hubble orbits in low Earth orbit at an altitude of approximately 540 kilometers (340 mi) and an inclination of 28.5°. The position along its orbit changes over time in
3731-659: The X-ray background, which would lead to future spectroscopic research. During this time, Barger was on faculty leave from the University of Wisconsin-Madison to conduct research at the University of Hawaii and had earned a grant from the National Science Foundation to fund her work. In 2002, she won the Newton Lacy Pierce Prize in Astronomy for outstanding achievement in observational astronomical research over
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3822-644: The construction of the OTA, Lockheed experienced some budget and schedule slippage, and by the summer 1985, construction of the spacecraft was 30% over budget and three months behind schedule. An MSFC report said Lockheed tended to rely on NASA directions rather than take their own initiative in the construction. The two initial, primary computers on the HST were the 1.25 MHz DF-224 system, built by Rockwell Autonetics, which contained three redundant CPUs, and two redundant NSSC-1 (NASA Standard Spacecraft Computer, Model 1) systems, developed by Westinghouse and GSFC using diode–transistor logic (DTL). A co-processor for
3913-487: The defective mirror by using sophisticated image processing techniques such as deconvolution . A commission headed by Lew Allen , director of the Jet Propulsion Laboratory , was established to determine how the error could have arisen. The Allen Commission found that a reflective null corrector , a testing device used to achieve a properly shaped non-spherical mirror, had been incorrectly assembled—one lens
4004-496: The desired impact of stimulating the astronomy community to renew their efforts on the lobbying front. While I like to think in hindsight it was a brilliant political move, I'm not sure I thought it through all that well. It was something that was spur of the moment. [...] $ 5 million would let them think that all is well anyway, but it's not. So let's give them a message. My own thinking, get them stimulated to get into action. Zeroing it out would certainly give that message. I think it
4095-428: The engineering side of the space telescope project, and the other to determine the scientific goals of the mission. Once these had been established, the next hurdle for NASA was to obtain funding for the instrument, which would be far more costly than any Earth-based telescope. The U.S. Congress questioned many aspects of the proposed budget for the telescope and forced cuts in the budget for the planning stages, which at
4186-519: The existence of supervoids such as the KBC void is consistent with ΛCDM. Galaxies inside a void experience a gravitational pull from outside the void, which yields a larger local value for the Hubble constant , a cosmological measure of how fast the universe expands. Some authors have proposed the structure as the cause of the discrepancy between measurements of the Hubble constant using galactic supernovae and Cepheid variables (72–75 km/s/Mpc) and from
4277-431: The existence of the spherical-shaped KBC Void, which is surrounded by a shell of galaxies, stars and other cosmic materials. Hubble Space Telescope The Hubble Space Telescope (often referred to as HST or Hubble ) is a space telescope that was launched into low Earth orbit in 1990 and remains in operation. It was not the first space telescope , but it is one of the largest and most versatile, renowned as
4368-581: The findings at a press conference at the 20th Texas Symposium on Relativistic Astrophysics, in Austin, Texas. In 2000, Barger became an assistant professor of astronomy at the University of Wisconsin-Madison while completing her University of Hawaii fellowship and eventually joining the faculty as a visiting adjunct astronomer. In 2001, she received the American Association of University Women Annie Jump Cannon Award in Astronomy for her investigation of
4459-405: The go-ahead, work on the program was divided among many institutions. Marshall Space Flight Center (MSFC) was given responsibility for the design, development, and construction of the telescope, while Goddard Space Flight Center was given overall control of the scientific instruments and ground-control center for the mission. MSFC commissioned the optics company Perkin-Elmer to design and build
4550-435: The ground to the spacecraft and saves money by allowing the use of modern programming languages. Additionally, some of the science instruments and components had their own embedded microprocessor-based control systems. The MATs (Multiple Access Transponder) components, MAT-1 and MAT-2, use Hughes Aircraft CDP1802CD microprocessors. The Wide Field and Planetary Camera (WFPC) also used an RCA 1802 microprocessor (or possibly
4641-472: The important role space-based observations could play in astronomy. In 1968, NASA developed firm plans for a space-based reflecting telescope with a mirror 3 m (9.8 ft) in diameter, known provisionally as the Large Orbiting Telescope or Large Space Telescope (LST), with a launch slated for 1979. These plans emphasized the need for crewed maintenance missions to the telescope to ensure such
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#17330845170304732-461: The intended −1.00230 . The same number was also derived by analyzing the null corrector used by Perkin-Elmer to figure the mirror, as well as by analyzing interferograms obtained during ground testing of the mirror. Because of the way the HST's instruments were designed, two different sets of correctors were required. The design of the Wide Field and Planetary Camera 2, already planned to replace
4823-459: The main source of star formation before the universe darkens as older galaxies fade away. Barger and her colleagues' research on the early Universe has informed cosmic stratigraphy, which is the process of obtaining redshifts of galaxies through deep-field images to chronologize galaxy and star formation since the Big Bang . The more redshifted galaxies are—or the closer to red the wavelength of
4914-415: The mirror being ground very precisely but to the wrong shape. During fabrication, a few tests using conventional null correctors correctly reported spherical aberration . But these results were dismissed, thus missing the opportunity to catch the error, because the reflective null corrector was considered more accurate. The commission blamed the failings primarily on Perkin-Elmer. Relations between NASA and
5005-421: The mirror to the required shape. However, in case their cutting-edge technology ran into difficulties, NASA demanded that PE sub-contract to Kodak to construct a back-up mirror using traditional mirror-polishing techniques. (The team of Kodak and Itek also bid on the original mirror polishing work. Their bid called for the two companies to double-check each other's work, which would have almost certainly caught
5096-425: The mirror's weight to a minimum it consisted of top and bottom plates, each 25 mm (0.98 in) thick, sandwiching a honeycomb lattice. Perkin-Elmer simulated microgravity by supporting the mirror from the back with 130 rods that exerted varying amounts of force. This ensured the mirror's final shape would be correct and to specification when deployed. Mirror polishing continued until May 1981. NASA reports at
5187-427: The mirror. While the commission heavily criticized Perkin-Elmer for these managerial failings, NASA was also criticized for not picking up on the quality control shortcomings, such as relying totally on test results from a single instrument. Many feared that Hubble would be abandoned. The design of the telescope had always incorporated servicing missions, and astronomers immediately began to seek potential solutions to
5278-429: The observing time on the telescope. Congress eventually approved funding of US$ 36 million for 1978, and the design of the LST began in earnest, aiming for a launch date of 1983. In 1983, the telescope was named after Edwin Hubble , who confirmed one of the greatest scientific discoveries of the 20th century, made by Georges Lemaître , that the universe is expanding . Once the Space Telescope project had been given
5369-654: The older 1801 version). The WFPC-1 was replaced by the WFPC-2 during Servicing Mission 1 in 1993, which was then replaced by the Wide Field Camera 3 (WFC3) during Servicing Mission 4 in 2009. The upgrade extended Hubble's capability of seeing deeper into the universe and providing images in three broad regions of the spectrum. When launched, the HST carried five scientific instruments: the Wide Field and Planetary Camera (WF/PC), Goddard High Resolution Spectrograph (GHRS), High Speed Photometer (HSP), Faint Object Camera (FOC) and
5460-411: The optics company had been severely strained during the telescope construction, due to frequent schedule slippage and cost overruns. NASA found that Perkin-Elmer did not review or supervise the mirror construction adequately, did not assign its best optical scientists to the project (as it had for the prototype), and in particular did not involve the optical designers in the construction and verification of
5551-595: The past five years. In October 2003, Barger was awarded a $ 625,000 Packard Foundation Fellowship for Science and Engineering toward her research. In 2005, the results of a study led by Barger concerning how black holes and galaxies grow was published in The Astronomical Journal . The team captured and observed long-exposure X-ray images of black holes normally obscured by gas and dust to determine that they are between one and 12 billion light-years away from Earth . With Chandra Deep Field North and South ,
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#17330845170305642-584: The polishing error that later caused problems .) The Kodak mirror is now on permanent display at the National Air and Space Museum . An Itek mirror built as part of the effort is now used in the 2.4 m telescope at the Magdalena Ridge Observatory . Construction of the Perkin-Elmer mirror began in 1979, starting with a blank manufactured by Corning from their ultra-low expansion glass. To keep
5733-425: The problem that could be applied at the first servicing mission, scheduled for 1993. While Kodak had ground a back-up mirror for Hubble, it would have been impossible to replace the mirror in orbit, and too expensive and time-consuming to bring the telescope back to Earth for a refit. Instead, the fact that the mirror had been ground so precisely to the wrong shape led to the design of new optical components with exactly
5824-576: The project. Hubble's cumulative costs are estimated to be about US$ 11.3 billion in 2015 dollars, which include all subsequent servicing costs, but not ongoing operations, making it the most expensive science mission in NASA history. Hubble accommodates five science instruments at a given time, plus the Fine Guidance Sensors , which are mainly used for aiming the telescope but are occasionally used for scientific astrometry measurements. Early instruments were replaced with more advanced ones during
5915-638: The rate of expansion of the universe . Space telescopes were proposed as early as 1923, and the Hubble telescope was funded and built in the 1970s by the United States space agency NASA with contributions from the European Space Agency . Its intended launch was in 1983, but the project was beset by technical delays, budget problems, and the 1986 Challenger disaster . Hubble was finally launched in 1990, but its main mirror had been ground incorrectly, resulting in spherical aberration that compromised
6006-596: The results of Barger and her colleagues' search for the origins of the cosmic X-ray background were presented at the 195th national meeting of the American Astronomical Society in Atlanta, Georgia. With the data they gathered from their research in the CXO, the team furthered previous research in finding that about one-third of the origins of the X-ray background are active galactic nuclei (AGNs) that emit light not on
6097-409: The same error but in the opposite sense, to be added to the telescope at the servicing mission, effectively acting as " spectacles " to correct the spherical aberration. The first step was a precise characterization of the error in the main mirror. Working backwards from images of point sources, astronomers determined that the conic constant of the mirror as built was −1.01390 ± 0.0002 , instead of
6188-428: The scientific community into fighting for full funding. As Hinners recalls: It was clear that year that we weren't going to be able to get a full-up start. There was some opposition on [Capitol] Hill to getting a new start on [Hubble]. It was driven, in large part as I recall, by the budget situation. Jim Fletcher proposed that we put in $ 5 million as a placeholder. I didn't like that idea. It was, in today's vernacular,
6279-489: The spectral and morphological transformation of the galaxies were affected by two different timescales and/or physical processes. Barger also used the Submillimetre Common-User Bolometer Array (SCUBA), a far- infrared camera , to discover new quasars, and as a 1999 Hubble Fellow and Chandra Fellow at large, she was granted access to NASA 's Chandra X-Ray Observatory (CXO). In January 2000,
6370-479: The stretched light from galaxies are—the older, brighter, less numerous and farther away they are from Earth. In 2013, Barger, former advisee Ryan Keenan and astronomer Lennox Cowie published the results of a study on the density of galactic matter in The Astrophysical Journal . The team used redshift surveys and spectroscopy to observe and estimate the distribution of luminous and dark matter in
6461-485: The systems to be used on the main satellite was dropped, and budgetary concerns also prompted collaboration with the European Space Agency (ESA). ESA agreed to provide funding and supply one of the first generation instruments for the telescope, as well as the solar cells that would power it, and staff to work on the telescope in the United States, in return for European astronomers being guaranteed at least 15% of
6552-497: The telescope accurately pointed during an observation, but can also be used to carry out extremely accurate astrometry ; measurements accurate to within 0.0003 arcseconds have been achieved. The Space Telescope Science Institute (STScI) is responsible for the scientific operation of the telescope and the delivery of data products to astronomers. STScI is operated by the Association of Universities for Research in Astronomy (AURA) and
6643-453: The telescope and instruments sit. Within the shell, a graphite-epoxy frame keeps the working parts of the telescope firmly aligned. Because graphite composites are hygroscopic , there was a risk that water vapor absorbed by the truss while in Lockheed's clean room would later be expressed in the vacuum of space; resulting in the telescope's instruments being covered by ice. To reduce that risk,
6734-400: The telescope until April 1985. Perkin-Elmer's schedules continued to slip at a rate of about one month per quarter, and at times delays reached one day for each day of work. NASA was forced to postpone the launch date until March and then September 1986. By this time, the total project budget had risen to US$ 1.175 billion. The spacecraft in which the telescope and instruments were to be housed
6825-403: The telescope's capabilities. The optics were corrected to their intended quality by a servicing mission in 1993. Hubble is the only telescope designed to be maintained in space by astronauts. Five Space Shuttle missions have repaired, upgraded, and replaced systems on the telescope, including all five of the main instruments. The fifth mission was initially canceled on safety grounds following
6916-654: The telescope. Her work as project scientist helped set the standards for NASA's operation of large scientific projects. Space-based astronomy had begun on a very small scale following World War II , as scientists made use of developments that had taken place in rocket technology. The first ultraviolet spectrum of the Sun was obtained in 1946, and NASA launched the Orbiting Solar Observatory (OSO) to obtain UV, X-ray, and gamma-ray spectra in 1962. An orbiting solar telescope
7007-449: The time consisted of very detailed studies of potential instruments and hardware for the telescope. In 1974, public spending cuts led to Congress deleting all funding for the telescope project. In 1977, then NASA Administrator James C. Fletcher proposed a token $ 5 million for Hubble in NASA's budget. Then NASA Associate Administrator for Space Science, Noel Hinners , instead cut all funding for Hubble, gambling that this would galvanize
7098-416: The time intervals for black hole growth and found that the activity of an abundance of black holes in nearby galaxies was greater and more recent than once thought. The team concluded that, contrary to widespread belief, not all black holes formed when galaxies did. Rather, there are black holes currently growing slowly, taking more than one billion years to form. In December 2000, Barger led the presentation of
7189-408: The time questioned Perkin-Elmer's managerial structure, and the polishing began to slip behind schedule and over budget. To save money, NASA halted work on the back-up mirror and moved the launch date of the telescope to October 1984. The mirror was completed by the end of 1981; it was washed using 9,100 L (2,000 imp gal; 2,400 US gal) of hot, deionized water and then received
7280-464: The turbulence in the atmosphere, which causes stars to twinkle, known to astronomers as seeing . At that time ground-based telescopes were limited to resolutions of 0.5–1.0 arcseconds , compared to a theoretical diffraction-limited resolution of about 0.05 arcsec for an optical telescope with a mirror 2.5 m (8 ft 2 in) in diameter. Second, a space-based telescope could observe infrared and ultraviolet light, which are strongly absorbed by
7371-409: The usefulness of the telescope for faint objects or high-contrast imaging. This meant nearly all the cosmological programs were essentially impossible, since they required observation of exceptionally faint objects. This led politicians to question NASA's competence, scientists to rue the cost which could have gone to more productive endeavors, and comedians to make jokes about NASA and the telescope. In
7462-478: The visible spectrum. The AGNs contain a massive black hole that produces X-rays as gas is pulled toward them at virtually the speed of light. The team also found that ultra-faint galaxies are a source of another third of the X-ray background. The ultra-faint galaxies emit little to no visible light due to dust formation around them or due to the absorption of visible light by cool gas. The team concluded that more optical observations with more powerful telescopes, such as
7553-656: The visible through the ultraviolet (shorter wavelengths) and was specified to be diffraction limited to take full advantage of the space environment. Therefore, its mirror needed to be polished to an accuracy of 10 nanometers, or about 1/65 of the wavelength of red light. On the long wavelength end, the OTA was not designed with optimum infrared performance in mind—for example, the mirrors are kept at stable (and warm, about 15 °C) temperatures by heaters. This limits Hubble's performance as an infrared telescope. Perkin-Elmer (PE) intended to use custom-built and extremely sophisticated computer-controlled polishing machines to grind
7644-406: The wrong shape. Although it was believed to be one of the most precisely figured optical mirrors ever made, smooth to about 10 nanometers, the outer perimeter was too flat by about 2200 nanometers (about 1 ⁄ 450 mm or 1 ⁄ 11000 inch). This difference was catastrophic, introducing severe spherical aberration, a flaw in which light reflecting off the edge of a mirror focuses on
7735-674: Was a Marshall scholar at King's College , University of Cambridge and received a doctor of philosophy in astronomy from the university in 1997. Barger holds positions as a Henrietta Leavitt Professor of Astronomy at the University of Wisconsin-Madison and as an affiliate graduate faculty member in the University of Hawaii Department of Physics and Astronomy. Barger's research discoveries concern distant Universe activity and objects, including dusty galaxies, quasars and supermassive black holes. Her research has overturned current and widely accepted models of how galaxies and supermassive black holes evolve. From 1996 to 2000, Barger received
7826-407: Was another major engineering challenge. It would have to withstand frequent passages from direct sunlight into the darkness of Earth's shadow , which would cause major changes in temperature, while being stable enough to allow extremely accurate pointing of the telescope. A shroud of multi-layer insulation keeps the temperature within the telescope stable and surrounds a light aluminum shell in which
7917-466: Was as simple as that. Didn't talk to anybody else about doing it first, just, "Let's go do that". Voila, it worked. Don't know whether I'd do that again. The political ploy worked. In response to Hubble being zeroed out of NASA's budget, a nationwide lobbying effort was coordinated among astronomers. Many astronomers met congressmen and senators in person, and large-scale letter-writing campaigns were organized. The National Academy of Sciences published
8008-525: Was due to be observed. Engineering support for HST is provided by NASA and contractor personnel at the Goddard Space Flight Center in Greenbelt, Maryland , 48 km (30 mi) south of the STScI. Hubble's operation is monitored 24 hours per day by four teams of flight controllers who make up Hubble's Flight Operations Team. By January 1986, the planned launch date for Hubble that October looked feasible, but
8099-602: Was launched in 1962 by the United Kingdom as part of the Ariel programme , and in 1966 NASA launched the first Orbiting Astronomical Observatory (OAO) mission. OAO-1's battery failed after three days, terminating the mission. It was followed by Orbiting Astronomical Observatory 2 (OAO-2), which carried out ultraviolet observations of stars and galaxies from its launch in 1968 until 1972, well beyond its original planned lifetime of one year. The OSO and OAO missions demonstrated
8190-414: Was out of position by 1.3 mm (0.051 in). During the initial grinding and polishing of the mirror, Perkin-Elmer analyzed its surface with two conventional refractive null correctors. However, for the final manufacturing step ( figuring ), they switched to the custom-built reflective null corrector, designed explicitly to meet very strict tolerances. The incorrect assembly of this device resulted in
8281-424: Was the work of Nancy Grace Roman , the "Mother of Hubble". Well before it became an official NASA project, she gave public lectures touting the scientific value of the telescope. After it was approved, she became the program scientist, setting up the steering committee in charge of making astronomer needs feasible to implement and writing testimony to Congress throughout the 1970s to advocate continued funding of
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