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87-566: The Far Ultraviolet Camera/Spectrograph was a tripod mounted, f/1.0, 75 mm electronographic Schmidt camera weighing 22 kg. It had a 20° field of view in the imaging mode, and 0.5x20° field in the spectrographic mode. Spectroscopic data were provided from 300 to 1350 Ångström , with 30 Å resolution, and images were provided in two passbands ranges, 1050–1260 Å and 1200–1550 Å. There were two corrector plates made of lithium fluoride (LiF) or calcium fluoride (CaF 2 ), which could be selected for different bands of UV. The camera contained

174-514: A cesium iodide (CsI) photocathode and used a film cartridge which was recovered and returned to earth for processing. The experiment was placed on the Descartes Highlands region of lunar surface where Apollo 16 astronauts John Young and Charles Duke landed in April 1972. To keep it cool and eliminate solar glare, it was placed in the shadow of the lunar module . It was manually aimed by

261-424: A random planetary orbit being along the line-of-sight to a star is the diameter of the star divided by the diameter of the orbit. For an Earth-size planet at 1  AU transiting a Sun-like star the probability is 0.47%, or about 1 in 210. For a planet like Venus orbiting a Sun-like star the probability is slightly higher, at 0.65%; If the host star has multiple planets, the probability of additional detections

348-462: A soft focus to provide excellent photometry , rather than sharp images. The mission goal was a combined differential photometric precision (CDPP) of 20 ppm for a m (V)=12 Sun-like star for a 6.5-hour integration, though the observations fell short of this objective (see mission status ). The focal plane of the spacecraft's camera is made out of forty-two 50 × 25 mm (2 × 1 in) CCDs at 2200×1024 pixels each, possessing

435-586: A candidate is a real planet. One of the methods, called doppler spectroscopy , requires follow-up observations from ground-based telescopes. This method works well if the planet is massive or is located around a relatively bright star. While current spectrographs are insufficient for confirming planetary candidates with small masses around relatively dim stars, this method can be used to discover additional massive non-transiting planet candidates around targeted stars. In multiplanetary systems, planets can often be confirmed through transit timing variation by looking at

522-412: A cost of about $ 20 million per year. NASA contacted the spacecraft using the X band communication link twice a week for command and status updates. Scientific data are downloaded once a month using the K a band link at a maximum data transfer rate of approximately 550  kB/s . The high gain antenna is not steerable so data collection is interrupted for a day to reorient the whole spacecraft and

609-546: A design was used to construct a working 1/8-scale model of the Palomar Schmidt, with a 5° field. The retronym "lensless Schmidt" has been given to this configuration. Yrjö Väisälä originally designed an "astronomical camera" similar to Bernhard Schmidt's "Schmidt camera", but the design was unpublished. Väisälä did mention it in lecture notes in 1924 with a footnote: "problematic spherical focal plane". Once Väisälä saw Schmidt's publication, he promptly went ahead and solved

696-416: A dielectric interference coating to minimize the formation of color centers and atmospheric moisture absorption. In terms of photometric performance, Kepler worked well, much better than any Earth-bound telescope, but short of design goals. The objective was a combined differential photometric precision (CDPP) of 20 parts per million (PPM) on a magnitude 12 star for a 6.5-hour integration. This estimate

783-485: A fixed field of view (FOV) against the sky. The diagram to the right shows the celestial coordinates and where the detector fields are located, along with the locations of a few bright stars with celestial north at the top left corner. The mission website has a calculator that will determine if a given object falls in the FOV, and if so, where it will appear in the photo detector output data stream. Data on exoplanet candidates

870-573: A further 3,199 unconfirmed planet candidates. Four planets have been confirmed through Kepler's K2 mission. In November 2013, astronomers estimated, based on Kepler space mission data, that there could be as many as 40 billion rocky Earth-size exoplanets orbiting in the habitable zones of Sun-like stars and red dwarfs within the Milky Way . It is estimated that 11 billion of these planets may be orbiting Sun-like stars. The nearest such planet may be 3.7 parsecs (12  ly ) away, according to

957-461: A large sample of stars to achieve several key goals: Most of the exoplanets previously detected by other projects were giant planets , mostly the size of Jupiter and bigger. Kepler was designed to look for planets 30 to 600 times less massive, closer to the order of Earth's mass (Jupiter is 318 times more massive than Earth). The method used, the transit method , involves observing repeated transit of planets in front of their stars, which causes

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1044-448: A mission lasting 7 to 8 years, as opposed to the originally planned 3.5 years, would be needed to find all transiting Earth-sized planets. On April 4, 2012, the Kepler mission was approved for extension through the fiscal year 2016, but this also depended on all remaining reaction wheels staying healthy, which turned out not to be the case (see Reaction wheel issues below). Kepler orbits

1131-650: A much higher probability of detecting Earth-sized planets than the Hubble Space Telescope , which has a field of view of only 10 sq. arc-minutes . Moreover, Kepler is dedicated to detecting planetary transits, while the Hubble Space Telescope is used to address a wide range of scientific questions, and rarely looks continuously at just one starfield. Of the approximately half-million stars in Kepler's field of view, around 150,000 stars were selected for observation. More than 90,000 are G-type stars on, or near,

1218-494: A multiple axis mount allowing it to follow satellites in the sky – were used by the Smithsonian Astrophysical Observatory to track artificial satellites from June 1958 until the mid-1970s. The Mersenne–Schmidt camera consists of a concave paraboloidal primary mirror, a convex spherical secondary mirror, and a concave spherical tertiary mirror. The first two mirrors (a Mersenne configuration) perform

1305-623: A process called dispositioning. Those which pass the dispositioning are called Kepler planet candidates. The KOI archive is not static, meaning that a Kepler candidate could end up in the false-positive list upon further inspection. In turn, KOIs that were mistakenly classified as false positives could end up back in the candidates list. Not all the planet candidates go through this process. Circumbinary planets do not show strictly periodic transits, and have to be inspected through other methods. In addition, third-party researchers use different data-processing methods, or even search planet candidates from

1392-463: A second one failed, disabling the collection of science data and threatening the continuation of the mission. On August 15, 2013, NASA announced that they had given up trying to fix the two failed reaction wheels. This meant the current mission needed to be modified, but it did not necessarily mean the end of planet hunting. NASA had asked the space science community to propose alternative mission plans "potentially including an exoplanet search, using

1479-424: A second reaction wheel failed on May 11, 2013, ending Kepler's primary mission. The spacecraft was put into safe mode, then from June to August 2013 a series of engineering tests were done to try to recover either failed wheel. By August 15, 2013, it was decided that the wheels were unrecoverable, and an engineering report was ordered to assess the spacecraft's remaining capabilities. This effort ultimately led to

1566-592: A signal that is easier to check, scientists expected the first reported results to be larger Jupiter-size planets in tight orbits. The first of these were reported after only a few months of operation. Smaller planets, and planets farther from their sun would take longer, and discovering planets comparable to Earth were expected to take three years or longer. Data collected by Kepler is also being used for studying variable stars of various types and performing asteroseismology , particularly on stars showing solar-like oscillations . Once Kepler has collected and sent back

1653-535: A site for future astronomical observatories. The film cartridge was removed during the third and final extravehicular activity , and returned to earth. The rest of the instrument package was left on the lunar surface. A total of 178 frames of film were obtained of 11 different targets including: the Earth's upper atmosphere and aurora, various nebulae and star clusters, and the Large Magellanic Cloud . The film

1740-455: A slight reduction in the star's apparent magnitude , on the order of 0.01% for an Earth-size planet. The degree of this reduction in brightness can be used to deduce the diameter of the planet, and the interval between transits can be used to deduce the planet's orbital period, from which estimates of its orbital semi-major axis (using Kepler's laws ) and its temperature (using models of stellar radiation) can be calculated. The probability of

1827-411: A spherical primary mirror. Schmidt corrector plates work because they are aspheric lenses with spherical aberration that is equal to but opposite of the spherical primary mirrors they are placed in front of. They are placed at the center of curvature " C " of the mirrors for a pure Schmidt camera and just behind the prime focus for a Schmidt–Cassegrain . The Schmidt corrector is thicker in the middle and

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1914-463: A threshold crossing event. These signals are individually inspected in two inspection rounds, with the first round taking only a few seconds per target. This inspection eliminates erroneously selected non-signals, signals caused by instrumental noise and obvious eclipsing binaries. Threshold crossing events that pass these tests are called Kepler Objects of Interest (KOI), receive a KOI designation and are archived. KOIs are inspected more thoroughly in

2001-423: A total resolution of 94.6 megapixels , which at the time made it the largest camera system launched into space. The array was cooled by heat pipes connected to an external radiator. The CCDs were read out every 6.5 seconds (to limit saturation) and co-added on board for 58.89 seconds for short cadence targets, and 1765.5 seconds (29.4 minutes) for long cadence targets. Due to the larger bandwidth requirements for

2088-434: A vacuum pan with the correct shape of the curve pre-shaped into the bottom of the pan, called a "master block". The upper exposed surface is then polished flat creating a corrector with the correct shape once the vacuum is released. This removes the need to have to hold a shape by applying an exact vacuum and allows for the mass production of corrector plates of the same exact shape. The technical difficulties associated with

2175-708: Is also a Schmidt camera. The Schmidt telescope of the Karl Schwarzschild Observatory is the largest Schmidt camera of the world. A Schmidt telescope was at the heart of the Hipparcos (1989–1993) satellite from the European Space Agency . This was used in the Hipparcos Survey which mapped the distances of more than a million stars with unprecedented accuracy: it included 99% of all stars up to magnitude 11. The spherical mirror used in this telescope

2262-445: Is higher than the probability of initial detection assuming planets in a given system tend to orbit in similar planes—an assumption consistent with current models of planetary system formation. For instance, if a Kepler -like mission conducted by aliens observed Earth transiting the Sun, there is a 7% chance that it would also see Venus transiting. Kepler's 115 deg field of view gives it

2349-429: Is mechanically conformed to the shape of the focal plane through the use of retaining clips or bolts, or by the application of a vacuum . A field flattener , in its simplest form a planoconvex lens in front of the film plate or detector, is sometimes used. Since the corrector plate is at the center of curvature of the primary mirror in this design the tube length can be very long for a wide-field telescope. There are also

2436-496: Is rarely used today. Holding the shape by constant vacuum is difficult and errors in the o-ring seal and even contamination behind the plate could induce optical errors. The glass plate could also break if bent enough to generate a curve for telescopes of focal ratio f/2.5 or faster. Also, for fast focal ratios, the curve obtained is not sufficiently exact and requires additional hand correction. A third method, invented in 1970 for Celestron by Tom Johnson and John O'rourke, uses

2523-559: Is submitted to the Kepler Follow-up Program , or KFOP, to conduct follow-up observations. Kepler's field of view covers 115 square degrees , around 0.25 percent of the sky, or "about two scoops of the Big Dipper". Thus, it would require around 400 Kepler-like telescopes to cover the whole sky. The Kepler field contains portions of the constellations Cygnus , Lyra , and Draco . The nearest star system in Kepler's field of view

2610-502: Is the Kepler space telescope exoplanet finder. Other related designs are the Wright camera and Lurie–Houghton telescope . The Schmidt camera was invented by Estonian-German optician Bernhard Schmidt in 1930. Its optical components are an easy-to-make spherical primary mirror , and an aspherical correcting lens , known as a Schmidt corrector plate , located at the center of curvature of

2697-401: Is the trinary star system Gliese 1245 , 15 light years from the Sun. The brown dwarf WISE J2000+3629, 22.8 ± 1 light years from the Sun is also in the field of view, but is invisible to Kepler due to emitting light primarily in infrared wavelengths. The scientific objective of the Kepler space telescope was to explore the structure and diversity of planetary systems . This spacecraft observes

Far Ultraviolet Camera/Spectrograph - Misplaced Pages Continue

2784-753: The Kepler Science Office (SO). Accordingly, the SOC develops the pipeline data processing software based on scientific algorithms developed jointly by the SO and SOC. During operations, the SOC: The SOC also evaluates the photometric performance on an ongoing basis and provides the performance metrics to the SO and Mission Management Office. Finally, the SOC develops and maintains the project's scientific databases, including catalogs and processed data. The SOC finally returns calibrated data products and scientific results back to

2871-638: The Schmidt or Schmidt–Cassegrain telescope designs. It was invented by Bernhard Schmidt in 1931, although it may have been independently invented by Finnish astronomer Yrjö Väisälä in 1924 (sometimes called the Schmidt–Väisälä camera as a result). Schmidt originally introduced it as part of a wide-field photographic catadioptric telescope , the Schmidt camera. It is now used in several other telescope designs, camera lenses and image projection systems that utilise

2958-647: The Schmidt telescope , is a catadioptric astrophotographic telescope designed to provide wide fields of view with limited aberrations . The design was invented by Bernhard Schmidt in 1930. Some notable examples are the Samuel Oschin telescope (formerly Palomar Schmidt), the UK Schmidt Telescope and the ESO Schmidt; these provided the major source of all-sky photographic imaging from 1950 until 2000, when electronic detectors took over. A recent example

3045-432: The high-gain antenna was changed from a design using a gimbal to one fixed to the frame of the spacecraft to reduce cost and complexity, at the cost of one observation day per month. The Ames Research Center was responsible for the ground system development, mission operations since December 2009, and scientific data analysis. The initial planned lifetime was three and a half years, but greater-than-expected noise in

3132-430: The main sequence . Thus, Kepler was designed to be sensitive to wavelengths of 400–865 nm where brightness of those stars peaks. Most of the stars observed by Kepler have apparent visual magnitude between 14 and 16 but the brightest observed stars have apparent visual magnitude of 8 or lower. Most of the planet candidates were initially not expected to be confirmed due to being too faint for follow-up observations. All

3219-463: The "K2" follow-on mission observing different fields near the ecliptic. In January 2006, the project's launch was delayed eight months because of budget cuts and consolidation at NASA. It was delayed again by four months in March 2006 due to fiscal problems. At this time, the high-gain antenna was changed from a gimballed design to one fixed to the frame of the spacecraft to reduce cost and complexity, at

3306-487: The 2012 National Medal of Technology and Innovation . A second spare telescope was slightly modified and later flown on Skylab 4 . It was given an aluminum (Al) and magnesium fluoride (MgF 2 ) mirror rather than rhenium . It was mounted on Skylab's Apollo Telescope Mount for usage in orbit. Among the many images and spectra that it took, it was used to study ultraviolet emission from Comet Kohoutek . Schmidt camera A Schmidt camera , also referred to as

3393-604: The DMC for long-term archiving, and distribution to astronomers around the world through the Multimission Archive at STScI (MAST). On July 14, 2012, one of the four reaction wheels used for fine pointing of the spacecraft failed. While Kepler requires only three reaction wheels to accurately aim the telescope, another failure would leave the spacecraft unable to aim at its original field. After showing some problems in January 2013,

3480-525: The Schmidt design directing light through a hole in the primary mirror creates a Schmidt–Cassegrain telescope . The last two designs are popular with telescope manufacturers because they are compact and use simple spherical optics. A short list of notable and/or large aperture Schmidt cameras. Kepler space telescope The Kepler space telescope is a defunct space telescope launched by NASA in 2009 to discover Earth-sized planets orbiting other stars . Named after astronomer Johannes Kepler ,

3567-490: The Sun , which avoids Earth occultations , stray light, and gravitational perturbations and torques inherent in an Earth orbit. NASA has characterized Kepler's orbit as "Earth-trailing". With an orbital period of 372.5 days, Kepler is slowly falling farther behind Earth (about 16 million miles per annum ). As of May 1, 2018 , the distance to Kepler from Earth was about 0.917 AU (137 million km). This means that after about 26 years Kepler will reach

Far Ultraviolet Camera/Spectrograph - Misplaced Pages Continue

3654-680: The UK Science Research Council with a 1.2 meter Schmidt telescope at Siding Spring Observatory engaged in a collaborative sky survey to complement the first Palomar Sky Survey, but focusing on the southern hemisphere. The technical improvements developed during this survey encouraged the development of the Second Palomar Observatory Sky Survey (POSS II). The telescope used in the Lowell Observatory Near-Earth-Object Search (LONEOS)

3741-509: The astronauts, who would re-point the telescope at targets throughout the lunar stay. The goals of the Far Ultraviolet Camera/Spectrograph spanned across several disciplines of astronomy . Earth studies were made by studying the Earth's upper atmosphere's composition and structure, the ionosphere , the geocorona , day and night airglow , and aurorae . Heliophysics studies were made by obtaining spectra and images of

3828-623: The billions of stars in the Milky Way have such planets, Kepler's sole scientific instrument is a photometer that continually monitored the brightness of approximately 150,000 main sequence stars in a fixed field of view. These data were transmitted to Earth, then analyzed to detect periodic dimming caused by exoplanets that cross in front of their host star. Only planets whose orbits are seen edge-on from Earth could be detected. Kepler observed 530,506 stars, and had detected 2,778 confirmed planets as of June 16, 2023. The Kepler space telescope

3915-558: The campus of Johns Hopkins University in Baltimore, Maryland . The science data telemetry is decoded and processed into uncalibrated FITS -format science data products by the DMC, which are then passed along to the Science Operations Center (SOC) at NASA Ames Research Center, for calibration and final processing. The SOC at NASA Ames Research Center (ARC) develops and operates the tools needed to process scientific data for use by

4002-453: The corrector by grinding and polishing the aspherical shape into a flat glass blank using specially shaped and sized tools. This method requires a high degree of skill and training on the part of the optical engineer creating the corrector. Schmidt himself worked out a second, more elegant, scheme for producing the complex figure needed for the correcting plate. A thin glass disk with a perfectly polished accurate flat surface on both sides

4089-421: The cost of one observation day per month. The Kepler observatory was launched on March 7, 2009, at 03:49:57 UTC aboard a Delta II rocket from Cape Canaveral Air Force Station , Florida. The launch was a success and all three stages were completed by 04:55 UTC. The cover of the telescope was jettisoned on April 7, 2009, and the first light images were taken on the next day. On April 20, 2009, it

4176-408: The data , from both the stars and the spacecraft, meant additional time was needed to fulfill all mission goals. Initially, in 2012, the mission was expected to be extended until 2016, but on July 14, 2012, one of the four reaction wheels used for pointing the spacecraft stopped turning, and completing the mission would only be possible if the other three all remained reliable. Then, on May 11, 2013,

4263-402: The data, raw light curves are constructed. Brightness values are then adjusted to take the brightness variations due to the rotation of the spacecraft into account. The next step is processing (folding) light curves into a more easily observable form and letting software select signals that seem potentially transit-like. At this point, any signal that shows potential transit-like features is called

4350-419: The drawbacks of having the obstruction of the film holder or detector mounted at the focus halfway up the tube assembly, a small amount of light is blocked and there is a loss in contrast in the image due to diffraction effects of the obstruction and its support structure. A Schmidt corrector plate is an aspheric lens which corrects the spherical aberration introduced by the spherical primary mirror of

4437-451: The edge. This corrects the light paths so light reflected from the outer part of the mirror and light reflected from the inner portion of the mirror is brought to the same common focus " F ". The Schmidt corrector only corrects for spherical aberration. It does not change the focal length of the system. Schmidt corrector plates can be manufactured in many ways. The most basic method, called the "classical approach", involves directly figuring

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4524-404: The field-flattening problem in Schmidt's design by placing a doubly convex lens slightly in front of the film holder. This resulting system is known as: Schmidt–Väisälä camera or sometimes as Väisälä camera . In 1940, James Baker of Harvard University modified the Schmidt camera design to include a convex secondary mirror, which reflected light back toward the primary. The photographic plate

4611-415: The former, these were limited in number to 512 compared to 170,000 for long cadence. However, even though at launch Kepler had the highest data rate of any NASA mission, the 29-minute sums of all 95 million pixels constituted more data than could be stored and sent back to Earth. Therefore, the science team pre-selected the relevant pixels associated with each star of interest, amounting to about 6 percent of

4698-713: The galaxy. Thus, the stars which Kepler observed are roughly the same distance from the Galactic Center as the Solar System , and also close to the galactic plane . This fact is important if position in the galaxy is related to habitability, as suggested by the Rare Earth hypothesis . Orientation is three-axis stabilized by sensing rotations using fine-guidance sensors located on the instrument focal plane (instead of rate sensing gyroscopes, e.g. as used on Hubble ). and using reaction wheels and hydrazine thrusters to control

4785-573: The high gain antenna for communications to Earth. The Kepler space telescope conducted its own partial analysis on board and only transmitted scientific data deemed necessary to the mission in order to conserve bandwidth. Science data telemetry collected during mission operations at LASP is sent for processing to the Kepler Data Management Center (DMC) which is located at the Space Telescope Science Institute on

4872-430: The mirror is specifically designed to have a mass only 14% that of a solid mirror of the same size. To produce a space telescope system with sufficient sensitivity to detect relatively small planets, as they pass in front of stars, a very high reflectance coating on the primary mirror was required. Using ion assisted evaporation , Surface Optics Corp. applied a protective nine-layer silver coating to enhance reflection and

4959-459: The object. Starting in the early 1970s, Celestron marketed an 8-inch Schmidt camera. The camera was focused in the factory and was made of materials with low expansion coefficients so it would never need to be focused in the field. Early models required the photographer to cut and develop individual frames of 35 mm film, as the film holder could only hold one frame of film. About 300 Celestron Schmidt cameras were produced. The Schmidt system

5046-500: The orientation. Kepler was operated out of Boulder, Colorado , by the Laboratory for Atmospheric and Space Physics (LASP) under contract to Ball Aerospace & Technologies . The spacecraft's solar array was rotated to face the Sun at the solstices and equinoxes , so as to optimize the amount of sunlight falling on the solar array and to keep the heat radiator pointing towards deep space. Together, LASP and Ball Aerospace controlled

5133-456: The other side of the Sun and will get back to the neighborhood of the Earth after 51 years. Until 2013 the photometer pointed to a field in the northern constellations of Cygnus , Lyra and Draco , which is well out of the ecliptic plane, so that sunlight never enters the photometer as the spacecraft orbits. This is also the direction of the Solar System's motion around the center of

5220-406: The pan until a particular negative pressure had been achieved. This caused the glass plate to warp slightly. The exposed upper surface of the glass was then ground and polished spherical. When the vacuum was released, the lower surface of the plate returned to its original flat form while the upper surface had the aspheric figure needed for a Schmidt corrector plate. Schmidt's vacuum figuring method

5307-471: The pixels (5.4 megapixels). The data from these pixels was then requantized, compressed and stored, along with other auxiliary data, in the on-board 16 gigabyte solid-state recorder. Data that was stored and downlinked includes science stars, p-mode stars , smear, black level, background and full field-of-view images. The Kepler primary mirror is 1.4 meters (4.6 ft) in diameter. Manufactured by glass maker Corning using ultra-low expansion (ULE) glass ,

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5394-405: The primary mirror. The film or other detector is placed inside the camera, at the prime focus. The design is noted for allowing very fast focal ratios , while controlling coma and astigmatism . Schmidt cameras have very strongly curved focal planes , thus requiring that the film, plate, or other detector be correspondingly curved. In some cases the detector is made curved; in others flat media

5481-834: The production of Schmidt corrector plates led some designers, such as Dmitri Dmitrievich Maksutov and Albert Bouwers , to come up with alternative designs using more conventional meniscus corrector lenses. Because of its wide field of view, the Schmidt camera is typically used as a survey instrument, for research programs in which a large amount of sky must be covered. These include astronomical surveys , comet and asteroid searches, and nova patrols. In addition, Schmidt cameras and derivative designs are frequently used for tracking artificial Earth satellites . The first relatively large Schmidt telescopes were built at Hamburg Observatory and Palomar Observatory shortly before World War II . Between 1945 and 1980, about eight more large (1 meter or larger) Schmidt telescopes were built around

5568-554: The remaining two good reaction wheels and thrusters". On November 18, 2013, the K2 "Second Light" proposal was reported. This would include utilizing the disabled Kepler in a way that could detect habitable planets around smaller, dimmer red dwarfs . On May 16, 2014, NASA announced the approval of the K2 extension. By January 2015, Kepler and its follow-up observations had found 1,013 confirmed exoplanets in about 440 star systems , along with

5655-420: The rest due to instrumental noise sources slightly larger than predicted. Because decrease in brightness from an Earth-size planet transiting a Sun-like star is so small, only 80 ppm, the increased noise means each individual transit is only a 2.7 σ event, instead of the intended 4 σ. This, in turn, means more transits must be observed to be sure of a detection. Scientific estimates indicated that

5742-436: The same day, bringing an end to its nine-year service. Kepler observed 530,506 stars and discovered 2,662 exoplanets over its lifetime. A newer NASA mission, TESS , launched in 2018, is continuing the search for exoplanets. The telescope has a mass of 1,039 kilograms (2,291 lb) and contains a Schmidt camera with a 0.95-meter (37.4 in) front corrector plate (lens) feeding a 1.4-meter (55 in) primary mirror —at

5829-457: The same function of the correcting plate of the conventional Schmidt. This form was invented by Paul in 1935. A later paper by Baker introduced the Paul-Baker design, a similar configuration but with a flat focal plane. The addition of a flat secondary mirror at 45° to the optical axis of the Schmidt design creates a Schmidt–Newtonian telescope . The addition of a convex secondary mirror to

5916-462: The scientists. On January 6, 2015, NASA announced the 1,000th confirmed exoplanet discovered by the Kepler space telescope. Four of the newly confirmed exoplanets were found to orbit within habitable zones of their related stars : three of the four, Kepler-438b , Kepler-442b and Kepler-452b , are almost Earth-size and likely rocky; the fourth, Kepler-440b , is a super-Earth . On May 10, 2016, NASA verified 1,284 new exoplanets found by Kepler,

6003-439: The selected stars are observed simultaneously, with the spacecraft measuring variations in their brightness every thirty minutes. This provides a better chance for seeing a transit. The mission was designed to maximize the probability of detecting planets orbiting other stars. Because Kepler must observe at least three transits to confirm that the dimming of a star was caused by a transiting planet, and because larger planets give

6090-407: The single largest finding of planets to date. Kepler data have also helped scientists observe and understand supernovae ; measurements were collected every half-hour so the light curves were especially useful for studying these types of astronomical events. On October 30, 2018, after the spacecraft ran out of fuel, NASA announced that the telescope would be retired. The telescope was shut down

6177-405: The solar wind, the solar bow cloud, and other gas clouds in the solar system. Astronomical studies by obtaining direct evidence of intergalactic hydrogen, and spectra of distant galaxy clusters and within the Milky Way. Lunar studies were conducted by detecting gasses in the lunar atmosphere, and searching for possible volcanic gasses. There were also considerations to evaluate the lunar surface as

6264-465: The spacecraft from a mission operations center located on the research campus of the University of Colorado . LASP performs essential mission planning and the initial collection and distribution of the science data. The mission's initial life-cycle cost was estimated at US$ 600 million, including funding for 3.5 years of operation. In 2012, NASA announced that the Kepler mission would be funded until 2016 at

6351-427: The spacecraft successfully sent its first science data to Earth. It was discovered that Kepler had entered safe mode on June 15. A second safe mode event occurred on July 2. In both cases the event was triggered by a processor reset . The spacecraft resumed normal operation on July 3 and the science data that had been collected since June 19 was downlinked that day. On October 14, 2009, the cause of these safing events

6438-450: The spacecraft was launched into an Earth-trailing heliocentric orbit . The principal investigator was William J. Borucki . After nine and a half years of operation, the telescope's reaction control system fuel was depleted, and NASA announced its retirement on October 30, 2018. Designed to survey a portion of Earth's region of the Milky Way to discover Earth-size exoplanets in or near habitable zones and to estimate how many of

6525-472: The time of its launch this was the largest mirror on any telescope outside Earth orbit, though the Herschel Space Observatory took this title a few months later. Its telescope has a 115 deg (about 12-degree diameter) field of view (FoV), roughly equivalent to the size of one's fist held at arm's length. Of this, 105 deg is of science quality, with less than 11% vignetting . The photometer has

6612-437: The transit signal. Another method to rule out planet candidates is astrometry for which Kepler can collect good data even though doing so was not a design goal. While Kepler cannot detect planetary-mass objects with this method, it can be used to determine if the transit was caused by a stellar-mass object. There are a few different exoplanet detection methods which help to rule out false positives by giving further proof that

6699-415: The unprocessed light curve data. As a consequence, those planets may be missing KOI designation. Once suitable candidates have been found from Kepler data, it is necessary to rule out false positives with follow-up tests. Usually, Kepler candidates are imaged individually with more-advanced ground-based telescopes in order to resolve any background objects which could contaminate the brightness signature of

6786-666: The world. One particularly famous and productive Schmidt camera is the Oschin Schmidt Telescope at Palomar Observatory , completed in 1948. This instrument was used in the National Geographic Society – Palomar Observatory Sky Survey (POSS, 1958), the POSS-II survey, the Palomar-Leiden (asteroid) Surveys, and other projects. The European Southern Observatory with a 1-meter Schmidt telescope at La Silla and

6873-546: Was announced that the Kepler science team had concluded that further refinement of the focus would dramatically increase the scientific return. On April 23, 2009, it was announced that the focus had been successfully optimized by moving the primary mirror 40  micrometers (1.6 thousandths of an inch) towards the focal plane and tilting the primary mirror 0.0072 degree. On May 13, 2009, at 00:01 UTC, Kepler successfully completed its commissioning phase and began its search for planets around other stars. On June 19, 2009,

6960-525: Was determined to be a low voltage power supply that provides power to the RAD750 processor. On January 12, 2010, one portion of the focal plane transmitted anomalous data, suggesting a problem with focal plane MOD-3 module, covering two out of Kepler's 42 CCDs . As of October 2010 , the module was described as "failed", but the coverage still exceeded the science goals. Kepler downlinked roughly twelve gigabytes of data about once per month. Kepler has

7047-407: Was developed allowing 10 ppm for stellar variability, roughly the value for the Sun. The obtained accuracy for this observation has a wide range, depending on the star and position on the focal plane, with a median of 29 ppm. Most of the additional noise appears to be due to a larger-than-expected variability in the stars themselves (19.5 ppm as opposed to the assumed 10.0 ppm), with

7134-717: Was digitally scanned and saved on tape. Files from these tapes can be requested at NASA. Most of the Apollo 16 and Skylab photos have been converted to JPGs by a third party enthusiast. The principal investigator and chief engineer of the Far Ultraviolet Camera/Spectrograph was Dr. George Robert Carruthers , who was working at the US Naval Research Lab . In 1969, Dr. Carruthers was given a patent for "Image Converter for Detecting Electromagnetic Radiation Especially in Short Wave Lengths". For this and his further work, he received

7221-518: Was extremely accurate; if scaled up to the size of the Atlantic Ocean , bumps on its surface would be about 10 cm high. The Kepler photometer , mounted on NASA's Kepler space telescope (2009–2018), is the largest Schmidt camera launched into space. In 1977 at Yerkes Observatory , a small Schmidt telescope was used to derive an accurate optical position for the planetary nebula NGC 7027 to allow comparison between photographs and radio maps of

7308-467: Was part of NASA's Discovery Program of relatively low-cost science missions. The telescope's construction and initial operation were managed by NASA's Jet Propulsion Laboratory , with Ball Aerospace responsible for developing the Kepler flight system. In January 2006, the project's launch was delayed eight months because of budget cuts and consolidation at NASA. It was delayed again by four months in March 2006 due to fiscal problems. During this time,

7395-406: Was placed on a heavy rigid metal pan. The top surface of the pan around the edge of the glass disk was ground at a precise angle or bevel based on the coefficient of elasticity of the particular type of glass that was being used. The glass plate was sealed to the ground edge of the pan. Then a vacuum pump was used to exhaust the air between the pan and glass through a small hole in the center of

7482-472: Was popular, used in reverse, for television projection systems, notably the Advent design by Henry Kloss . Large Schmidt projectors were used in theaters, but systems as small as 8 inches were made for home use and other small venues. In the 1930s, Schmidt noted that the corrector plate could be replaced with a simple aperture at the mirror's center of curvature for a slow (numerically high f-ratio) camera. Such

7569-574: Was then installed near the primary, facing the sky. This variant is called the Baker-Schmidt camera. The Baker–Nunn design, by Baker and Joseph Nunn , replaces the Baker-Schmidt camera's corrector plate with a small triplet corrector lens closer to the focus of the camera. It used a 55 mm wide film derived from the Cinemascope 55 motion picture process. A dozen f/0.75 Baker-Nunn cameras with 20-inch apertures – each weighing 3.5 tons including

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