What kind of telescope was used to get pictures of the black hole?
Event Horizon Telescope
The Event Horizon Telescope (EHT) is a project to create a large telescope array consisting of a global network of radio telescopes and combining data from several very-long-baseline interferometry (VLBI) stations around the Earth. The aim is to observe the immediate environment of the supermassive black hole Sagittarius A* at the center of the Milky Way, as well as the even larger black hole in the supergiant elliptical galaxy Messier 87, with angular resolution comparable to the black hole's event horizon.
Halton Arp
Since the 1960s, telescopes and astronomical instrumentation have advanced greatly: the Hubble Space Telescope was launched, and cosmological theory and observation has advanced considerably. Black holes and supermassive black holes have been directly as well as indirectly detected, extremely distant objects are routinely studied and contextualized, and multiple 8-10 meter telescopes (such as those at Keck Observatory and the Very Large Telescope) have become operational, and detectors such as CCDs are now more widely employed. These developments, have led to quasars being understood to be very distant active galaxies with high redshifts. Many imaging surveys, most notably the Hubble Deep Field, have found many high-redshift objects that are not QSOs but that appear to be normal galaxies like those found nearby. The spectra of the high-redshift galaxies, as seen from X-ray to radio wavelengths, match the spectra of nearby galaxies (particularly galaxies with high levels of star formation activity but also galaxies with normal or extinguished star formation activity) when corrected for redshift effects.
Félix Aguilar Observatory
The principal telescope of EACUC is a double astrograph consisting of two lenses each 20-inches (50.8 cm) in diameter, one designed for blue light and the other for yellow light. The lenses focus the light separately onto two photographic plates with dimensions of 17×17 inches (43×43 cm). The photographic plates are purchased in the U.S., shipped to Argentina, exposed in the telescope, developed, and then shipped back to the U.S. In New Haven, Connecticut, the plates are measured with a precision measuring machine.
Andrew Ainslie Common
In 1879 he bought a new mirror from Calver to mount in a larger Newtonian reflecting telescope he was building. He used it to make further observations of satellites of Mars and Saturn, and was able to see Saturn's moon Mimas and show that the ephemeris of its orbit was incorrect. With this instrument he also obtained a photograph of a comet in 1881, C/1881 K1. His most notable work with this telescope were the long time exposures he made of the Orion Nebula between 1880 and 1884. His 1883 photograph of that nebula for the first time showed photography's ability to record stars and other features invisible to the human eye. Common noted of his own photographs that:
These pictures earned Common the Gold Medal of the Royal Astronomical Society in 1884. Common eventually sold the 36-inch reflector to British politician Edward Crossley who gave it to Lick Observatory in 1895, becoming the Crossley telescope at that observatory.
New Technology Telescope
Although other pre-existing telescopes such as the Nordic Optical Telescope had lightweight mirrors supported by actuators, the NTT is claimed to be the first telescope using full active optics. Its design as well as the design of its enclosure (the building protecting it) included many revolutionary features, from whence it was named. In particular, great care was taken to ensure a good ventilation of the telescope, and to avoid heat sources in around the telescope. Since its construction, the NTT has undergone several upgrades which continued to improve its quality. It was used as a real-life test bench for the engineering concepts and software used for the Very Large Telescope.
Field of view
In astronomy, the field of view is usually expressed as an angular area viewed by the instrument, in square degrees, or for higher magnification instruments, in square arc-minutes. For reference the Wide Field Channel on the Advanced Camera for Surveys on the Hubble Space Telescope has a field of view of 10 sq. arc-minutes, and the High Resolution Channel of the same instrument has a field of view of 0.15 sq. arc-minutes. Ground-based survey telescopes have much wider fields of view. The photographic plates used by the UK Schmidt Telescope had a field of view of 30 sq. degrees. The 1.8 m (71 in) Pan-STARRS telescope, with the most advanced digital camera to date has a field of view of 7 sq. degrees. In the near infra-red WFCAM on UKIRT has a field of view of 0.2 sq. degrees and the VISTA telescope has a field of view of 0.6 sq. degrees. Until recently digital cameras could only cover a small field of view compared to photographic plates, although they beat photographic plates in quantum efficiency, linearity and dynamic range, as well as being much easier to process.
Supermassive black hole
The Hubble Space Telescope, launched in 1990, provided the resolution needed to perform more refined observations of galactic nuclei. In 1994 the Faint Object Spectrograph on the Hubble was used to observe Messier 87, finding that ionized gas was orbiting the central part of the nucleus at a velocity of ±500 km/s. The data indicated a concentrated mass of lay within a span, providing strong evidence of a supermassive black hole. Using the Very Long Baseline Array to observe Messier 106 , Miyoshi et al. (1995) were able to demonstrate that the emission from an HO maser in this galaxy came from a gaseous disk in the nucleus that orbited a concentrated mass of , which was constrained to a radius of 0.13 parsecs. They noted that a swarm of solar mass black holes within a radius this small would not survive for long without undergoing collisions, making a supermassive black hole the sole viable candidate.
Lovell Telescope
Between 1972 and 1973, the telescope was used for "a detailed survey of the radio sources in a limited area of the sky … up to the sensitivity limit of the instrument". Among the objects catalogued was the first gravitational lens, which was confirmed optically in 1979 after its position was found to coincide with a pair of faint blue stars by using the Mark I as an interferometer with the Mark II. The telescope was also involved in the detection of the first Einstein ring in 1998, in conjunction with observations made with the Hubble Space Telescope.
Jack B. Newton
In 1991 Newton became the first amateur astrophotographer to make full (RGB) color CCD images of celestial objects using a Santa Barbara Instruments Group ST-4 camera, making a full color CCD image of M57, the "Ring Nebula" and M27, the "Dumbbell Nebula". He took three separate black and white images, each taken with a separate filter in red, blue, and green, which were later combined in software that was being developed for amateur astrophotography by Richard Berry, then editor of "Astronomy" magazine. Berry published the first combined color CCD image of M27 as his magazine's cover.
List of deep fields
In astronomy, a deep field is an image of a portion of the sky taken with a very long exposure time, in order to detect and study faint objects. The depth of the field refers to the apparent magnitude or the flux of the faintest objects that can be detected in the image. Deep field observations usually cover a small angular area on the sky, because of the large amounts of telescope time required to reach faint flux limits. Deep fields are used primarily to study galaxy evolution and the cosmic evolution of active galactic nuclei, and to detect faint objects at high redshift. Numerous ground-based and space-based observatories have taken deep-field observations at wavelengths spanning radio to X-rays, and the first deep-field image to receive a great deal of public attention was the Hubble Deep Field, observed in 1995 with the WFPC2 camera on the Hubble Space Telescope. Other space telescopes that have obtained deep-field observations include the Chandra X-ray Observatory, the XMM-Newton Observatory, and the Spitzer Space Telescope.
Orchard Hill Observatory
The Orchard Hill Observatory is an astronomical observatory located at the highest point on the University of Massachusetts Amherst campus. Constructed in 1965, the observatory is a red brick building with a 16-inch Cassegrain reflector optical telescope. It is used for several community events and is regularly open for public viewing on Thursday nights. Originally the observatory was home to a 20” telescope, given to the department by an avid amateur who lived in central Massachusetts. It was a 1/10 scale model (loosely) of a larger 200” scope. Eventually, a crack was spotted during one of the re-aluminizings of the 20” mirror and the scope was no more. In the meantime, the department had been granted money associated with its move from Hasbrouck to the Grad Research Tower to buy a small telescope and put in on top of the GRC. The GRC had a small "isolation" pad built on its roof, which was supposed to be a mount for the scope, which could be accessed via a small open elevator. However, the GRC had terrible noise and gross vibration problems. The isolation pad never worked and there were too many safety concerns about using the roof of the building for observing. A 16" telescope was later bought from Competition Associates (a racing car company). That scope arrived in 1976 but because of the problems with using the top of the GRC, the scope was never mounted there. In fact, it sat in the basement of Hasbrouck for perhaps 10 years, becoming known as the "Subterranean Telescope.” This situation finally led to the 20" being disassembled and the 16" scope being moved to Orchard Hill and installed in the dome there. The 16" was a major improvement in usability. As to what happened to the 20", the mirror may have been stored in the Astronomy Research Facility but the drive was most likely not kept.
Observatory House
Observatory House was an observatory in Slough, England. It was built, run and used by the astronomer William Herschel, and his sister Caroline. The famous '40-foot telescope' - at that time the largest in the world - was housed there in the late 18th century and early 19th century.
Milagro (experiment)
Milagro (the Spanish word for miracle) was a ground-based water Cherenkov radiation telescope situated in the Jemez Mountains near Los Alamos, New Mexico at the Fenton Hill Observatory site. It was primarily designed to detect gamma rays but also detected large numbers of cosmic rays. It operated in the TeV region of the spectrum at an altitude of 2530 m. Like conventional telescopes, Milagro was sensitive to light but the similarities ended there. Whereas "normal" astronomical telescopes view the universe in visible light, Milagro saw the universe at very high energies. The light that Milagro saw was about 1 trillion times more energetic than visible light. While these particles of light, known as photons, are the same as the photons that make up visible light, they behave quite differently due to their high energies.
Comet Hale–Bopp
Bopp did not own a telescope. He was out with friends near Stanfield, Arizona, observing star clusters and galaxies when he chanced across the comet while at the eyepiece of his friend's telescope. He realized he might have spotted something new when, like Hale, he checked his star maps to determine if any other deep-sky objects were known to be near M70, and found that there were none. He alerted the Central Bureau for Astronomical Telegrams through a Western Union telegram. Brian G. Marsden, who had run the bureau since 1968, laughed, "Nobody sends telegrams anymore. I mean, by the time that telegram got here, Alan Hale had already e-mailed us three times with updated coordinates."
Zenith telescope
Other types of zenith telescopes include the Monument to the Great Fire of London, which includes a central shaft meant for use as a zenith telescope. High-precision (and fixed building) zenith telescopes were also used until the early 1980s to track Earth's north pole position e.g. Earth's rotation axis position. Since then radio astronomical quasar measurements have also measured Earth's rotation axis several orders of magnitude more accurately than optical tracking. The NASA Orbital Debris Observatory, which used a 3 m diameter aperture liquid mirror, and the Large Zenith Telescope, which uses a 6 m diameter aperture liquid mirror, are both zenith telescopes, as the use of liquid mirror meant these telescopes could only point straight up.
Faint Object Camera
The Faint Object Camera (FOC) was a camera installed on the Hubble Space Telescope from launch in 1990 until 2002. It was replaced by the Advanced Camera for Surveys. In December 1993, Hubble's vision was corrected on STS-61 by installing COSTARS, which corrected the problem with Hubble's mirror before it reached an instrument like FOC. Later instruments had this correction built in, which is why it was possible to later remove COSTARS itself and replace it with a new science instrument.
Lovell Telescope
Bernard Lovell built the Transit Telescope at Jodrell Bank in the late 1940s. This was a -diameter radio telescope that could only point directly upwards; the next logical step was to build a telescope that could look at all parts of the sky so that more sources could be observed, as well as for longer integration times. Although the Transit Telescope had been designed and constructed by the astronomers that used it, a fully steerable telescope would need to be professionally designed and constructed; the first challenge was to find an engineer willing to do the job. This turned out to be Charles Husband, whom Lovell first met on 8 September 1949.
Two bearing assemblies from 15-inch (38-cm) gun turrets were bought cheaply in 1950; these came from the World War I battleships HMS "Revenge" and "Royal Sovereign", which were being broken up at the time. The bearings became the two main altitude rotator bearings of the telescope, with the appropriate parts of the telescope being designed around them. Husband presented the first drawings of the proposed giant, fully steerable radio telescope in 1950. After refinements, these plans were detailed in a "Blue Book", which was presented to the DSIR on 20 March 1951; the proposal was approved in March 1952.
William Herschel Telescope
The WHT has been used to make many significant new discoveries. Some of the more notable include the first evidence of a supermassive black hole (Sgr A*) at the centre of the Milky Way (in 1995) and the first optical observation of a gamma-ray burst (GRB 970228) (in 1997).
Stratoscope
Stratoscope I possessed a 12-inch (30.48 cm) mirror and was first flown in 1957. It was conceived by Martin Schwarzschild and built by the Perkin Elmer Corporation. A small secondary mirror focussed the image from the primary into a 35 mm movie camera, which captured the images on film. Schwarzschild used the telescope to study the turbulence and granulation in the Sun's photosphere.
Stratoscope II, a 36-inch (91.4 cm) reflecting telescope, flew from 1963 to 1971. The gondola it was mounted on weighed 3.5 tons. It studied planetary atmospheres, the atmospheres of red giant stars, and galaxies. On early flights of Stratoscope II, photographic film was used, but this was soon replaced by television detectors.
Jerry Nelson (astronomer)
In 1977, when Nelson worked in the Physics Division of the Lawrence Berkeley National Laboratory, he was appointed to a five-person committee to design a 10-meter telescope, twice the diameter of the best telescope of the time. He concluded that only a segmented design would be sensible to overcome structural difficulties. His design had 36 hexagonal mirror segments, each six feet in diameter and just three inches thick. This led to the creation of the revolutionary twin 10-meter Keck telescopes.
"The Hale Telescope was very innovative for its day, but in terms of advancing the state of the art--or at least pushing the available technology to its limits--it's been downhill ever since for optical telescopes. It is time for a forward step, not just making improvements in an old design."
 —Jerry Nelson
Dutch Open Telescope
The Dutch Open Telescope (DOT) is an optical solar telescope located on Roque de los Muchachos Observatory, La Palma (near the Swedish 1-m Solar Telescope). With a main mirror of 45 centimeter, it can reach an 0.2 arcsec resolution for sustained periods. For further optimisation of the images, the DOT uses the image despeckle mechanism. It was used to record the 2004 Venus transit.
Dark Energy Survey
The survey uses the 4-meter Victor M. Blanco Telescope located at Cerro Tololo Inter-American Observatory (CTIO) in Chile, outfitted with the Dark Energy Camera (DECam). This camera allows for more sensitive images in the red part of the visible spectrum and in the near infrared, in comparison to previous instruments.
Lamont–Hussey Observatory
The LHO's primary instrument was a refracting telescope for its entire span of operations. The lenses for the telescope were initially ordered in 1911, but due to the First World War, the two lens blanks were not delivered by Carl Zeiss Jena until 1923. They were then figured by James B. McDowell and Frederick Hageman of John A. Brashear, Co., a process which took over a year. The finished lenses were sent to Ann Arbor, where they were integrated into the great refractor built by the Detroit Observatory's machine shop. The device was tested in Michigan and then shipped to South Africa, where it was installed and began operating in 1928.
Carl Otto Lampland
He first went to Lowell Observatory in 1902 when invited by Percival Lowell and Lampland was closely involved with Lowell in planetary observation. He designed cameras used for astronomy and also designed and maintained telescopes, including resilvering the mirror of the telescope. He also constructed thermocouples and used them to measure temperatures of planets. He won the Royal Photographic Society Medal in 1905 for the camera which he designed for the 24-inch Clark telescope. Together with William Coblentz, he measured large differences between the day and night temperatures on Mars which implied a thin Martian atmosphere. He discovered the asteroid 1604 Tombaugh. In 1907 Lampland and Lowell won a Royal Photographic Society exhibition medal for their photographs of Mars.
Hinode (satellite)
A modified Wolter I telescope design that uses grazing incidence optics to image the solar corona's hottest components (0.5 to 10 Million K) with an angular resolution consistent with 1 arcsec pixels at the CCD. The telescope has an imaging field of view of 34 arcminutes. It is capable of capturing an image of the full sun when pointed at the center of the solar disk. The telescope was designed and built by Smithsonian Astrophysical Observatory (SAO), which, with the Harvard College Observatory (HCO) form the Harvard-Smithsonian Center for Astrophysics (CfA). The camera was developed by NAOJ and JAXA.
Large Synoptic Survey Telescope
The Large-aperture Synoptic Survey Telescope (LSST) is a 6.5-m-class optical telescope designed to survey the visible sky every week down to a much fainter level than that reached by existing surveys. It will catalog 90 percent of the near-Earth objects larger than 300 m and assess the threat they pose to life on Earth. It will find some 10,000 primitive objects in the Kuiper Belt, which contains a fossil record of the formation of the solar system. It will also contribute to the study of the structure of the universe by observing thousands of supernovae, both nearby and at large redshift, and by measuring the distribution of dark matter through gravitational lensing. All the data will be available through the National Virtual Observatory (see below under “Small Initiatives”), providing access for astronomers and the public to very deep images of the changing night sky.
Early development was funded by a number of small grants, with major contributions in January 2008 by software billionaires Charles Simonyi and Bill Gates of $20 and $10 million respectively. $7.5 million was included in the U.S. President's FY2013 NSF budget request. The Department of Energy is funding construction of the digital camera component by the SLAC National Accelerator Laboratory, as part of its mission to understand dark energy.
X-ray astronomy
X-rays from the Sun were detected by the U.S. Naval Research Laboratory Blossom experiment on board. An Aerobee 150 rocket was launched on June 12, 1962 and it detected the first X-rays from other celestial sources (Scorpius X-1). It is now known that such X-ray sources as Sco X-1 are compact stars, such as neutron stars or black holes. Material falling into a black hole may emit X-rays, but the black hole itself does not. The energy source for the X-ray emission is gravity. Infalling gas and dust is heated by the strong gravitational fields of these and other celestial objects. Based on discoveries in this new field of X-ray astronomy, starting with Scorpius X-1, Riccardo Giacconi received the Nobel Prize in Physics in 2002.
Hale Telescope
The chief optical designer for Hale's previous 100-inch telescope was George Willis Ritchey, who intended the new telescope to be of Ritchey–Chrétien design. Compared to the usual parabolic primary, this design would have provided sharper images over a larger usable field of view. However, Ritchey and Hale had a falling-out. With the project already late and over budget, Hale refused to adopt the new design, with its complex curvatures, and Ritchey left the project. The Mount Palomar Hale Telescope turned out to be the last world-leading telescope to have a parabolic primary mirror.
James Gregory Telescope
The James Gregory Telescope is the largest working optical telescope in the UK and is still used by the School of Physics and Astronomy for research in collaborative projects such as SuperWASP and the study of super massive black holes and their impact on galaxy structure.
David Malin
These techniques were initially devised to enhance the scientific return from photography, but Malin is now best known for the series of three-colour wide field images of deep space objects which have been widely published as posters and in books around the world. Most professional astronomical photographs are monochromatic; if colour pictures are required, three images are needed. During his career at the AAO, Malin made about 150 three-colour images of deep sky objects, mostly using plates taken with the Anglo-Australian Telescope and the UK Schmidt Telescope.
Fan Mountain Observatory
Fan Mountain Observatory (or Fan Mountain Station of Leander McCormick Observatory), an observatory operated by the Astronomy Department of the University of Virginia in southern Albemarle County, Virginia. It was opened in 1966 with a Tinsley reflector, with a Baker-Schmidt astrometric reflector following in 1972, to extend the parallax work of the McCormick Observatory, which was suffering from light pollution from growing Charlottesville, Virginia by this time. Today both telescopes have been outfitted with state-of-the-art instruments and are operated nightly by university students and faculty. The primary instruments for the telescope are a 2048x2048 SITe CCD for direct imaging and a fiber-fed visible wavelength spectrograph, FOBOS, for general spectroscopy and precision radial velocity measurement. The telescope supports a 1024x1024 HAWAII-1 based HgCdTe infrared camera operating between 0.8 and 2.5 µm. This camera is capable of direct imaging in an 8.5 x 8.5' (2.5 x 2.5 mrad) field with 0.5" (2.4 µrad) pixels as well as polarimetry and grism spectroscopy.
Mount Wilson Observatory
In 1968, the first large-area near-IR (2.2 µm) survey of the sky was conducted by Gerry Neugebauer and Robert B. Leighton using a 157 cm reflecting dish they had built in the early 1960s. Known as the Caltech Infrared Telescope, it operated in an unguided drift scanning mode using a lead(II) sulfide (PbS) photomultiplier read out on paper charts. The telescope is now on display at the Udvar-Hazy Center, part of the Smithsonian Air and Space Museum.The Observatory was a filming location in a space themed episode of "Check It Out! with Dr. Steve Brule".
William Parsons, 3rd Earl of Rosse
During the 1840s, he had the Leviathan of Parsonstown built, a 72-inch (6 feet/1.83 m) telescope at Birr Castle, Parsonstown, County Offaly. The telescope replaced a telescope that he had built previously.
He had to invent many of the techniques he used for constructing the Leviathan, both because its size was without precedent and because earlier telescope builders had guarded their secrets or had simply failed to publish their methods. Details of the metal, casting, grinding and polishing of the 3-ton 'speculum' were presented in 1844 at the Belfast Natural History Society. Rosse's telescope was considered a marvellous technical and architectural achievement, and images of it were circulated widely within the British commonwealth. Building of the Leviathan began in 1842 and it was first used in 1845; regular use waited another two years, due to the Great Irish Famine. It was the world's largest telescope, in terms of aperture size, until the early 20th century. Using this telescope Rosse saw and catalogued a large number of nebulae (including a number that would later be recognised as galaxies).
Lord Rosse performed astronomical studies and discovered the spiral nature of some nebulas, today known to be spiral galaxies. Rosse's telescope Leviathan was the first to reveal the spiral structure of M51, a galaxy nicknamed later as the "Whirlpool Galaxy", and his drawings of it closely resemble modern photographs.
Telescope
Telescopes are optical instruments that make distant objects appear magnified by using an arrangement of lenses or curved mirrors and lenses, or various devices used to observe distant objects by their emission, absorption, or reflection of electromagnetic radiation. The first known practical telescopes were refracting telescopes invented in the Netherlands at the beginning of the 17th century, by using glass lenses. They found use in both terrestrial applications and astronomy.
All Sky Automated Survey for SuperNovae
Initially, there were four ASAS-SN telescopes at Haleakala and another four at Cerro Tololo, an LCOGT site. Twelve more telescopes were deployed in 2017 in Chile, South Africa and Texas, with funds from the Moore Foundation, the Ohio State University, the Mount Cuba Astronomical Foundation, China, Chile, Denmark, and Germany. All the telescopes (Nikon telephoto f400/2.8 lenses) have a diameter of 14 cm and ProLine PL230 CCD cameras. The pixels in the cameras span 7.8 arc seconds, so follow up observations on other telescopes are usually required to get a more accurate location.
Extreme ultraviolet Imaging Telescope
The Extreme ultraviolet Imaging Telescope (EIT) is an instrument on the SOHO spacecraft used to obtain high-resolution images of the solar corona in the ultraviolet range. The EIT instrument is sensitive to light of four different wavelengths: 17.1, 19.5, 28.4, and 30.4 nm, corresponding to light produced by highly ionized iron (XI)/(X), (XII), (XV), and helium (II), respectively. EIT is built as a single telescope with a quadrant structure to the entrance mirrors: each quadrant reflects a different colour of EUV light, and the wavelength to be observed is selected by a shutter that blocks light from all but the desired quadrant of the main telescope.
Royal Observatory, Edinburgh
Over the years 1973–1979 the ROE built the 3.8-metre UK Infrared Telescope (UKIRT) on Mauna Kea in Hawaii. This is an early example of the use of thin mirrors in large telescopes. The ROE operated UKIRT in cooperation with the University of Hawaii and built instruments for it, including the first ever common-user infrared camera. In 1987 the James Clerk Maxwell Telescope (JCMT) – also on Mauna Kea – was handed over to the ROE after the Rutherford Appleton Laboratory had completed its construction. The JCMT is a 15-metre diameter, millimetre- and sub-millimetre-wavelength telescope, which was run by a partnership of the UK, the Netherlands and Canada until 2014.
Astrophotography
The beginning of the 20th century saw the worldwide construction of refracting telescopes and sophisticated large reflecting telescopes specifically designed for photographic imaging. Towards the middle of the century, giant telescopes such as the Hale Telescope and the Samuel Oschin telescope at Palomar Observatory were pushing the limits of film photography.
Hobby–Eberly Telescope
Since achieving first light in 1996, the telescope has been used for a wide variety of studies ranging from the Solar System to stars in our galaxy and studies of other galaxies. The telescope has been used successfully to find planets orbiting around other stars by measuring radial velocities as precisely as 1 m/s. Using the low-resolution spectrograph, the telescope has been used to identify Type Ia supernovae to measure the acceleration of the universe. The telescope has also been used to measure the rotation of individual galaxies. The telescope was upgraded for use in the Hobby–Eberly Telescope Dark Energy Experiment (HETDEX), which will provide the first observations to allow narrowing of the list of possible explanations for dark energy.
History of the telescope
Since speculum metal mirror secondaries or diagonal mirrors greatly reduced the light that reached the eyepiece, several reflecting telescope designers tried to do away with them. In 1762 Mikhail Lomonosov presented a reflecting telescope before the Russian Academy of Sciences forum. It had its primary mirror tilted at four degrees to telescope's axis so the image could be viewed via an eyepiece mounted at the front of the telescope tube without the observer's head blocking the incoming light. This innovation was not published until 1827, so this type came to be called the Herschelian telescope after a similar design by William Herschel.
About the year 1774 William Herschel (then a teacher of music in Bath, England) began to occupy his leisure hours with the construction of reflector telescope mirrors, finally devoted himself entirely to their construction and use in astronomical research. In 1778, he selected a reflector mirror (the best of some 400 telescope mirrors which he had made) and with it, built a focal length telescope. Using this telescope, he made his early brilliant astronomical discoveries. In 1783, Herschel completed a reflector of approximately in diameter and focal length. He observed the heavens with this telescope for some twenty years, replacing the mirror several times. In 1789 Herschel finished building his largest reflecting telescope with a mirror of and a focal length of , (commonly known as his 40-foot telescope) at his new home, at Observatory House in Slough, England. To cut down on the light loss from the poor reflectivity of the speculum mirrors of that day, Herschel eliminated the small diagonal mirror from his design and tilted his primary mirror so he could view the formed image directly. This design has come to be called the Herschelian telescope. He discovered Saturn's sixth known moon, Enceladus, the first night he used it (August 28, 1789), and on September 17, its seventh known moon, Mimas. This telescope was world's largest telescope for over 50 years. However, this large scope was difficult to handle and thus less used than his favorite 18.7-inch reflector.
Dobsonian telescope
A Dobsonian telescope is an altazimuth-mounted Newtonian telescope design popularized by John Dobson in 1965 and credited with vastly increasing the size of telescopes available to amateur astronomers. Dobson's telescopes featured a simplified mechanical design that was easy to manufacture from readily available components to create a large, portable, low-cost telescope. The design is optimized for observing faint, deep-sky objects such as nebulae and galaxies. This type of observation requires a large objective diameter (i.e. light-gathering power) of relatively short focal length and portability for travel to relatively less light-polluted locations.
BlackGEM
Each telescope is equipped with a 10,000 by 10,000 pixel CCD with 9 micron pixel size that samples the full focal plane of the telescope. This, combined with the (f/5.5) focal length of the telescope, means that the angular resolution of the instrument is limited only by the seeing (which is about 1 arcsecond at La Silla). This enables spectroscopic follow-up of any detected gravitational wave source with for instance the nearby Very Large Telescope.
Newtonian telescope
Newton built his reflecting telescope because he suspected it could prove his theory that white light is composed of a spectrum of colours. Colour distortion (chromatic aberration) was the primary fault of refracting telescopes of Newton's day, and there were many theories as to what caused it. During the mid-1660s with his work on the theory of colour, Newton concluded this defect was caused by the lens of the refracting telescope behaving the same as prisms he was experimenting with, breaking white light into a rainbow of colours around bright astronomical objects. If this were true, then chromatic aberration could be eliminated by building a telescope which did not use a lens – a reflecting telescope.
Lowell Observatory Near-Earth-Object Search
LONEOS, in its final configuration, used a 0.6-meter f/1.8 Schmidt telescope, acquired from Ohio Wesleyan University in 1990, and a Lowell-built 16 megapixel CCD detector. This combination of instruments provided a field of view of 2.88 by 2.88 degrees (8.3 square degrees). It had a maximum nightly scan area of about 1,000 square degrees (covered four times). The instrument could cover the entire accessible dark sky in about a month. The CCD has detected asteroids as faint as visual magnitude 19.8 but its typical limiting visual magnitude was 19.3. The instrument is located at Lowell Observatory's dark sky site, Anderson Mesa Station, near Flagstaff, Arizona, USA.
Hale Telescope
The Hale Telescope is a , 3.3 reflecting telescope at the Palomar Observatory in California, US, named after astronomer George Ellery Hale. With funding from the Rockefeller Foundation in 1928, he orchestrated the planning, design, and construction of the observatory, but with the project ending up taking 20 years he did not live to see its commissioning. The Hale was groundbreaking for its time, with double the diameter of the second-largest telescope, and pioneered many new technologies in telescope mount design and in the design and fabrication of its large aluminum coated "honeycomb" low thermal expansion Pyrex mirror. It was completed in 1948 and is still in active use.
Infrared astronomy
As is the case for visible light telescopes, space is the ideal place for infrared telescopes. In space, images from infrared telescopes can achieve higher resolution, as they do not suffer from blurring caused by the Earth's atmosphere, and are also free from absorption caused by the Earth's atmosphere. Current infrared telescopes in space include the Herschel Space Observatory, the Spitzer Space Telescope, and the Wide-field Infrared Survey Explorer. Since putting telescopes in orbit is expensive, there are also airborne observatories, such as the Stratospheric Observatory for Infrared Astronomy and the Kuiper Airborne Observatory. These observatories place telescopes above most, but not all, of the atmosphere, which means there is absorption of infrared light from space by water vapor in the atmosphere.
One of the most common infrared detector arrays used at research telescopes is HgCdTe arrays. These operate well between 0.6 and 5 micrometre wavelengths. For longer wavelength observations or higher sensitivity other detectors may be used, including other narrow gap semiconductor detectors, low temperature bolometer arrays or photon-counting Superconducting Tunnel Junction arrays.
Harvard College Observatory
Between 1847 and 1852 Bond and pioneer photographer John Adams Whipple used the Great Refractor telescope to produce images of the moon that are remarkable in their clarity of detail and aesthetic power. This was the largest telescope in North America at that time, and their images of the moon took the prize for technical excellence in photography at the 1851 Great Exhibition at The Crystal Palace in London. On the night of July 16–17, 1850, Whipple and Bond made the first daguerreotype of a star (Vega).
Edwin Hubble
Edwin Hubble's arrival at Mount Wilson Observatory, California in 1919 coincided roughly with the completion of the Hooker Telescope, then the world's largest. At that time, the prevailing view of the cosmos was that the universe consisted entirely of the Milky Way Galaxy. Using the Hooker Telescope at Mt. Wilson, Hubble identified Cepheid variables (a kind of star that is used as a means to determine the distance from the galaxy – see also standard candle) in several spiral nebulae, including the Andromeda Nebula and Triangulum. His observations, made in 1924, proved conclusively that these nebulae were much too distant to be part of the Milky Way and were, in fact, entire galaxies outside our own, suspected by researchers at least as early as 1755 when Immanuel Kant's General History of Nature and Theory of the Heavens appeared. This idea had been opposed by many in the astronomy establishment of the time, in particular by Harvard University-based Harlow Shapley. Despite the opposition, Hubble, then a thirty-five-year-old scientist, had his findings first published in "The New York Times" on , 1924, then presented them to other astronomers at the January 1, 1925 meeting of the American Astronomical Society. Hubble's results for Andromeda were not formally published in a peer-reviewed scientific journal until 1929.
Event Horizon Telescope
Each year since its first data capture in 2006, the EHT array has moved to add more observatories to its global network of radio telescopes. The first image of the Milky Way's supermassive black hole, Sagittarius A*, was expected to be produced in April 2017, but owing to the South Pole Telescope being closed during winter (April to October) the data shipment delayed the processing to December 2017, when the shipment arrived. A date for the release of the image has not yet been announced. The image will also test Albert Einstein's general theory of relativity at the extreme.
UK Schmidt Telescope
The UKST is a Schmidt camera, with a design based on the Oschin Schmidt Telescope. It is a survey telescope with a 6° by 6° field of view, originally imaged onto a 35 cm square glass photographic plate, and was the primary source of optical survey data in the southern sky from the 1970s to after 2000. The original sky survey plates were digitally scanned by the Space Telescope Science Institute to create the Guide Star Catalog for the Hubble Space Telescope, and the Digitized Sky Survey.
Large Binocular Telescope
The Large Binocular Telescope (LBT) is an optical telescope for astronomy located on Mount Graham, in the Pinaleno Mountains of southeastern Arizona, United States. It is a part of the Mount Graham International Observatory. The LBT is currently one of the world's most advanced optical telescopes; using two 8.4 m (330 inch) wide mirrors, with centres 14.4 m apart, it has the same light-gathering ability as an 11.8 m (464 inch) wide single circular telescope and detail of a 22.8 m (897 inch) wide one. Its mirrors individually are the joint second-largest optical telescope in continental North America, behind the Hobby–Eberly Telescope in West Texas; it is also the largest monolithic, or , in an optical telescope. Strehl ratios of 60–90% in the infrared H band and 95% in the infrared M band have been achieved by the LBT.
Henry Fitz
Fitz contributed considerably in the development of astronomical photography. Making telescopes and related astronomical components was a labor of love for him. Often he would be found working after midnight. He was the best known American maker of telescopes and achromatic instruments before the Civil War.
Fitz was in partnership with Wolcott and developed a patented Daguerrotype camera. They had a photographic studio in Baltimore in 1841. Fitz invented and built foot power machines for the grinding of lenses. He also had employees do all the other tasks involved and trained them accordingly in the process of making lenes and mirrors. The critical final mirror polishing he did himself, however, and did not allow his employees to do that. Fitz made a six-inch (152 mm) refractor telescope in 1845 for the American Institute Fair for which he received a gold medal.
Astronomical seeing
The first answer to this problem was speckle imaging, which allowed bright objects with simple morphology to be observed with diffraction-limited angular resolution. Later came NASA's Hubble Space Telescope, working outside the atmosphere and thus not having any seeing problems and allowing observations of faint targets for the first time (although with poorer resolution than speckle observations of bright sources from ground-based telescopes because of Hubble's smaller telescope diameter). The highest resolution visible and infrared images currently come from imaging optical interferometers such as the Navy Prototype Optical Interferometer or Cambridge Optical Aperture Synthesis Telescope, but those can only be used on very bright stars.
Orion Nebula
In 1865 English amateur astronomer William Huggins used his visual spectroscopy method to examine the nebula showing it, like other nebulae he had examined, was made up of "luminous gas". On September 30, 1880 Henry Draper used the new dry plate photographic process with an 11-inch (28 cm) refracting telescope to make a 51-minute exposure of the Orion Nebula, the first instance of astrophotography of a nebula in history. Another set of photographs of the nebula in 1883 saw breakthrough in astronomical photography when amateur astronomer Andrew Ainslie Common used the dry plate process to record several images in exposures up to 60 minutes with a 36-inch (91 cm) reflecting telescope that he constructed in the backyard of his home in Ealing, outside London. These images for the first time showed stars and nebula detail too faint to be seen by the human eye.
Uppsala Southern Schmidt Telescope
The Uppsala Schmidt Telescope was moved to Siding Spring Observatory from Mount Stromlo Observatory in 1982. The instrument has been used to study the galaxy, asteroids and comets. It was last dedicated to the Siding Spring Survey. The telescope had a field of view of just over 6° through the use of a correcting plate, making its field three times as large as that of the Anglo-Australian Telescope. It used a spherical rather than a parabolic mirror with 0.6 m correcting plate to achieve this. Photographic plates and film were used as detectors.
Hipparcos
The spacecraft carried a single all-reflective, eccentric Schmidt telescope, with an aperture of . A special beam-combining mirror superimposed two fields of view, 58 degrees apart, into the common focal plane. This complex mirror consisted of two mirrors tilted in opposite directions, each occupying half of the rectangular entrance pupil, and providing an unvignetted field of view of about 1°×1°. The telescope used a system of grids, at the focal surface, composed of 2688 alternate opaque and transparent bands, with a period of 1.208 arc-sec (8.2 micrometre). Behind this grid system, an image dissector tube (photomultiplier type detector) with a sensitive field of view of about 38-arc-sec diameter converted the modulated light into a sequence of photon counts (with a sampling frequency of 1200 Hz) from which the phase of the entire pulse train from a star could be derived. The apparent angle between two stars in the combined fields of view, modulo the grid period, was obtained from the phase difference of the two star pulse trains. Originally targeting the observation of some 100,000 stars, with an astrometric accuracy of about 0.002 arc-sec, the final "Hipparcos Catalogue" comprised nearly 120,000 stars with a median accuracy of slightly better than 0.001 arc-sec (1 milliarc-sec).
Transformation optics
The first experimental demonstration of electromagnetic black hole at microwave frequencies occurred in October 2009. The proposed black hole was composed of non-resonant, and resonant, metamaterial structures, which can absorb electromagnetic waves efficiently coming from all directions due to the local control of electromagnetic fields. It was constructed of a thin cylinder at 21.6 centimeters in diameter comprising 60 concentric rings of metamaterials. This structure created a gradient index of refraction, necessary for bending light in this way. However, it was characterized as being artificially inferior substitute for a real black hole. The characterization was justified by an abosorption of only 80% in the microwave range, and that it has no internal source of energy. It is singularly a light absorber. The light absorption capability could be beneficial if it could be adapted to technologies such as solar cells. However, the device is limited to the microwave range.
Hubble Deep Field South
The Hubble Deep Field South is a composite of several hundred individual images taken using the Hubble Space Telescope's Wide Field and Planetary Camera 2 over 10 days in September and October 1998. It followed the great success of the original Hubble Deep Field in facilitating the study of extremely distant galaxies in early stages of their evolution. While the WFPC2 took very deep optical images, nearby fields were simultaneously imaged by the Space Telescope Imaging Spectrograph (STIS) and the Near Infrared Camera and Multi-Object Spectrometer (NICMOS).
NGC 2261
NGC 2261 was imaged as Palomar Observatory's Hale Telescope's first light by Edwin Hubble on January 26, 1949, some 20 years after the Palomar Observatory project began in 1928. Hubble had studied the nebula previously at Yerkes and Mt. Wilson. Hale had taken photographic plates with a 24 inch (60.96 cm) reflecting telescope in 1916. Also, plates were taken using the same telescope in 1908 by FC Jordan, this allowed Hale to use of a blink comparator to study any changes in the nebula.
Palomar Observatory
The camera for the Palomar QUEST Survey was a mosaic of 112 Charge-coupled devices (CCDs) covering the whole (4 degree by 4 degree) field of view of the Schmidt telescope, the largest CCD mosaic used in an astronomical camera when built. This instrument was used to produce The Big Picture, the largest astronomical photograph ever produced. The Big Picture is on display at Griffith Observatory.
Amateur astronomy
With the development of fast Internet in the last part of the 20th century along with advances in computer controlled telescope mounts and CCD cameras "Remote Telescope" astronomy is now a viable means for amateur astronomers not aligned with major telescope facilities to partake in research and deep sky imaging. This enables anyone to control a telescope a great distance away in a dark location. The observer can image through the telescope using CCD cameras. The digital data collected by the telescope is then transmitted and displayed to the user by means of the Internet. An example of a digital remote telescope operation for public use via the Internet is the Bareket observatory, and there are telescope farms in New Mexico, Australia and Atacama in Chile.
Isaac Newton Telescope
Today, it is used mostly with the Wide Field Camera (WFC), a four CCD instrument with a field of view of 0.56x0.56 square degrees which was commissioned in 1997. The other main instrument available at the INT is the Intermediate Dispersion Spectrograph (IDS), recently re-introduced having been unavailable for a period of several years.
Solo operations of Apollo 15
During the 1971 Apollo 15 mission to the Moon, and its three days of exploration on the lunar surface by David Scott and James Irwin, Command Module Pilot (CMP) Al Worden had a busy schedule of observations. Apollo 15 was the first mission to carry the Scientific Instrument Module (SIM) bay, which contained a panoramic camera, gamma ray spectrometer, mapping camera, laser altimeter and mass spectrometer. Worden had to operate the shutter and lenses on the cameras and turn on and off the various instruments. During the coast back to Earth, he would perform an EVA to retrieve film cassettes from the cameras.
Many of his observations were of far side features that had not been seen in great detail. The panoramic camera was a modified version of the U.S. Air Force's KA-80A camera for its spy satellites, using a 610 mm f/3.5 lens. This particular camera was similar to those used by the Lockheed U-2, A-12 "Oxcart" and SR-71 "Blackbird". It could see features as small as 3 ft (1 m) across on the lunar surface. It would take long strips, 205 by 13 mi (330 by 21 km) of the surface, on 3.8 foot by 4.5 inch (114.8 by 11.4 cm) strips of film. Over the course of the mission it would take 1,529 usable images, exposing 2 km of film. The film cassette weighed 55 lb (25 kg).
Lamont–Hussey Observatory
The 27-inch telescope's foremost use was to study binary stars, a subject of great interest to both Hussey and Rossiter. In 1956 it was used by Earl C. Slipher to photograph Mars at opposition. In 1974, after closure of the observatory, the telescope was dismantled and the lenses were shipped back to Michigan. The telescope tube and other parts remained in South Africa, and are on display at the Erlich Park Fire Station Museum. In January 2019 the telescope tube and other parts were reassembled as an exhibit at the Naval Hill Planetarium.
Skyhook balloon
On August 19, 1957, an unmanned Skyhook balloon lifted the first Project Stratoscope telescope. Project Stratoscope I was a program developed to research the Sun. Instruments included a 12-inch (30-centimeter) telescope with a special light-sensitive pointing system and a closed circuit television camera that was guided by the scientists on the ground. This was the first balloon-borne telescope. The telescope took more than 400 photographs of sunspots. These were the sharpest photographs taken of the Sun up to that time. The photographs increased scientists' understanding of the motions observed in the strong magnetic fields of the sunspots.
William Herschel Telescope
The AAT was completed in 1974, at which point the British Science and Engineering Research Council began planning for a group of three telescopes located in the northern hemisphere (now known as the Isaac Newton Group of Telescopes, ING). The telescopes were to be a (which became the Jacobus Kapteyn Telescope), the Isaac Newton Telescope which was to be moved from its existing site at Herstmonceux Castle, and a 4m class telescope, initially planned as a . A new site was chosen at an altitude of on the island of La Palma in the Canary Islands, that is now the Observatorio del Roque de los Muchachos. The project was led by the Royal Greenwich Observatory (RGO), who also operated the telescopes until control passed to an independent ING when the RGO closed in 1998.
Large Synoptic Survey Telescope
The telescope uses a novel 3-mirror design, a variant of three-mirror anastigmat, which allows a compact telescope to deliver sharp images over a very wide 3.5-degree diameter field of view. Images will be recorded by a 3.2-gigapixel CCD imaging camera, the largest digital camera ever constructed. The telescope is located on the El Peñón peak of Cerro Pachón, a 2,682-meter-high mountain in Coquimbo Region, in northern Chile, alongside the existing Gemini South and Southern Astrophysical Research Telescopes. The LSST Base Facility is located about away by road, in the town of La Serena.
2015 TG387
was first observed on 13 October 2015 at the Mauna Kea Observatory , by American astronomers David Tholen, Scott Sheppard, and Chad Trujillo during their astronomical survey for objects located beyond the Kuiper Cliff. The unofficial discovery was publicly announced on 1 October 2018. The survey uses two principal telescopes: For the Northern hemisphere, the 8.2-meter Subaru Telescope with its Hyper Suprime Camera at Mauna Kea Observatories, Hawaii, and for the Southern hemisphere, the 4-meter Blanco telescope and its Dark Energy Camera at Cerro Tololo Inter-American Observatory in Chile. For follow-up observations to determine an object's orbit, the astronomers are using the Magellan and the Discovery Channel telescopes. The survey's discoveries include , and .
Pan-STARRS
The initial telescope, PS1, saw first light using a low-resolution camera in June 2006. The telescope has a 3° field of view, which is extremely large for telescopes of this size, and is equipped with the largest digital camera ever built, recording almost 1.4 billion pixels per image. The focal plane has 60 separately mounted close packed CCDs arranged in an 8 × 8 array. The corner positions are not populated, because the optics do not illuminate the corners. Each CCD device, called an Orthogonal Transfer Array (OTA), has 4800 × 4800 pixels, separated into 64 cells, each of 600 × 600 pixels. This gigapixel camera or 'GPC' saw first light on August 22, 2007, imaging the Andromeda Galaxy.
National Geographic Society – Palomar Observatory Sky Survey
The photographs were taken with the 48-inch Samuel Oschin telescope at Palomar Observatory, and the astronomical survey was funded by a grant from the National Geographic Society to the California Institute of Technology. Among the primary minds behind the project were Edwin Hubble, Milton L. Humason, Walter Baade, Ira Sprague Bowen and Rudolph Minkowski. The first photographic plate was exposed on November 11, 1949. 99% of the plates were taken by June 20, 1956, but the final 1% was not completed until December 10, 1958.
Dark Energy Survey
DECam, the new camera installed at the Victor M. Blanco Telescope by the DES collaboration, brings new observational possibilities that were not available for previous surveys, such as the Sloan Digital Sky Survey. One significant difference between previous CCD at the Victor M. Blanco Telescope and DECam is the improved quantum efficiency in the red part of the visible spectra and in the near infrared. This is a very important property for the observation of very distant sources, like Type IA supernovae or galaxy cluster, because the expansion of the universe shifts the photons emitted from a given source towards redder wavelengths. On the other hand, Silicon, which is the main element used to make CCDs, becomes transparent for infrared light, and this issue made the development of the DECam CCD a technological challenge.
The Black Hole
Although "Star Wars" had revolutionized the use of computerized motion control miniature effects, "The Black Hole" was shot using a blend of traditional camera techniques and newly developed computer-controlled camera technology. Disney wanted to rent equipment from Industrial Light and Magic, but it was unavailable during the film's production period and was prohibitively expensive. In the end, Disney turned to its own engineering department, which created the A.C.E.S. (Automated Camera Effects System). The computerized system allowed for the camera to take double exposure photographs of the miniature models as it moves convincingly across the matte painting. It also permitted the actors to move unrestrictedly within a matte painting, and the camera tracks them within a non-existent set that would be painted in later. The Mattescan system was then used to composite live-action shots onto a single matte painting while the camera is in motion on several axes. In total, 150 matte paintings were created for the film under the supervision of Harrison Ellenshaw, but only 13 were used in the film.
Warren De la Rue
He took some of the very first photos of the moon, so he got a crater named after him the "De La Rue (crater)".
In 1860 De La Rue took the photoheliograph to Spain for the purpose of photographing the total solar eclipse which occurred on 18 July of that year.
This expedition formed the subject of the Bakerian Lecture already referred to. The photographs obtained on that occasion proved beyond doubt the solar character of the prominences or red flames, seen around the limb of the moon during a solar eclipse. In 1873 De La Rue gave up active work in astronomy, and presented most of his astronomical instruments to the university observatory, Oxford. Subsequently, in the year 1887, he provided the same observatory with a 13-inch refractor to enable it to take part in the International Photographic Survey of the Heavens.
Lurie–Houghton telescope
The Houghton telescope or Lurie–Houghton telescope is a catadioptric telescope. Houghton's original design was patented in 1944. Instead of the fairly hard to make Schimdt and heavy heavy meniscus (Maksutov) corrector lenses, the corrector for the Houghton is relatively easy to make. It consists of two lenses: a positive and a negative, set at the front of the telescope which fixes the telescope's aperture. All lens and mirror surfaces are spheroidal, which eases construction. These lenses are relatively thin, though not as thin as the Schmidt corrector. With a good anti-reflective coating, light loss and "ghost" reflections are minimal.
Asteroid Terrestrial-impact Last Alert System
The full ATLAS concept consists of eight 50-centimeter diameter f/2 Wright-Schmidt telescopes, spread over the globe for full-sky and 24h/24h coverage, and each fitted with a 110 Megapixel CCD array camera. The current system consists of two such telescopes operating on Haleakala and Mauna Loa in the Hawaiian Islands, ATLAS1 and ATLAS2. A major feature of these telescopes is their large 7.4° field of view - about 15 times the diameter of the full moon- of which their 10 500 x 10 500 CCD camera images the central 5.42° x 5.42°. This system can image the whole night sky visible from Hawaii with about 1000 separate telescope pointings. At 30 seconds per exposure plus 5 seconds for readout, each ATLAS telescope can therefore scan the whole visible sky a little over once each night, with a median completeness limit at apparent magnitude 19. Since the mission of the telescope is to identify moving objects, each telescope actually observes one quarter of the sky four times in a night at approximately 15-minute intervals, as needed to automatically link multiple observations of an asteroid into a preliminary orbit and predict its approximate position on subsequent nights. Apparent magnitude 19 is astronomer-speak for "respectably but not extremely faint", and it is the equivalent to the light of a match flame in New York viewed from San Francisco. ATLAS therefore scans the visible sky in much less depth, but much more quickly, than larger surveying telescope arrays such as University of Hawaii's Pan-STARRS. Pan-STARRS goes approximately 100 times deeper, but needs weeks instead of half a night to scan the whole sky just once.
George Ellery Hale
George Ellery Hale (June 29, 1868 – February 21, 1938) was an American solar astronomer, best known for his discovery of magnetic fields in sunspots, and as the leader or key figure in the planning or construction of several world-leading telescopes; namely, the 40-inch refracting telescope at Yerkes Observatory, 60-inch Hale reflecting telescope at Mount Wilson Observatory, 100-inch Hooker reflecting telescope at Mount Wilson, and the 200-inch Hale reflecting telescope at Palomar Observatory.
Long Range Reconnaissance Imager
Long Range Reconnaissance Imager (LORRI) is a telescope aboard the "New Horizons" spacecraft for imaging. LORRI has been used to image Jupiter and its moons and especially Pluto and its system of moons since its launched in 2006. LORRI is a reflecting telescope of Ritchey-Chrétien design, and it has a main mirror diameter of 20.8 cm (8.2 inches) across. Images are taken with a CCD capturing data with 1024 × 1024 pixels. LORRI is a telescopic panchromatic imager integrated with the "New Horizons" spacecraft, and it is one of seven major science instruments on the probe. LORRI does not have any moving parts and is pointed by moving the entire "New Horizons" spacecraft. LORRI has a narrow field of view, less than a third of one degree.
Jean Mueller
The Second Palomar Observatory Sky Survey (POSS II) got underway in August 1985, with the first of the 14" photographic glass plates being pulled off the Palomar's Samuel Oschin telescope (then called the 48-inch Schmidt Camera). Jean Mueller was hired as the "48-Inch Night Assistant" in July of that year, and worked in the capacity as observer and telescope operator for the duration. She took over 5500 photographic plates and had the honor of setting the telescope and removing the very last plate from the historic Schmidt Camera on June 3, 2000, as well as discovering her very last supernova, 2000cm, on that same night.
Astrophotography
The late 20th century saw advances in astronomical imaging take place in the form of new hardware, with the construction of giant multi-mirror and segmented mirror telescopes. It would also see the introduction of space based telescopes, such as the Hubble Space Telescope. Operating outside the atmosphere’s turbulence, scattered ambient light and the vagaries of weather allows the Hubble Space Telescope, with a mirror diameter of , to record stars down to the 30th magnitude, some 100 times dimmer than what the 5-meter Mount Palomar Hale telescope could record in 1949.
Wisconsin Ultraviolet Photo-Polarimeter Experiment
The Wisconsin Ultraviolet Photo-Polarimeter Experiment (WUPPE) was a space telescope with a 50cm diameter mirror for spectroscopy and polarimetry in the ultraviolet spectral range. It was used in conjunction with other telescopes on the shuttle missions STS-35 (ASTRO-1 in December 1990) and STS-67 (ASTRO-2 in March 1995).
Ritchey–Chrétien telescope
Ritchey intended the 100-inch Mount Wilson Hooker telescope (1917) and the 200-inch (5 m) Hale Telescope to be RCTs. His designs would have provided sharper images over a larger usable field of view compared to the parabolic designs actually used. However, Ritchey and Hale had a falling-out. With the 100-inch project already late and over budget, Hale refused to adopt the new design, with its hard-to-test curvatures, and Ritchey left the project. Both projects were then built with traditional optics. Since then, advances in optical measurement and fabrication have allowed the RCT design to take over - the Hale telescope, dedicated in 1948, turned out to be the last world-leading telescope to have a parabolic primary mirror.
Telescope (goldfish)
Black telescopes are descendants of a type of wild carp known as Silver Prussian Carp or Gibel Carp, this fish is believed to originate from China in the 1400s. In the 1500s they were traded in Japan, and lastly, in the 1800s, they made their way to the USA. It is widely accepted they were a result of selective fish breeding by Chinese who first called them Dragon Fish or Dragon Eyes.
Víctor M. Blanco Telescope
Currently the main research instrument used at the telescope is the "Dark Energy Camera" (DECam), the camera used in the Dark Energy Survey. DECam saw its first light in September 2012.
Great Paris Exhibition Telescope of 1900
The telescope had two interchangeable objective lenses (for visual and photographic use respectively) in diameter, with a focal length of . Due to its extremely large size, the telescope was mounted in a fixed horizontal position. Light from astronomical objects was redirected into the optical tube assembly via a Foucault siderostat, a movable plane mirror in diameter, mounted in a large cast-iron frame at the objective lens end of the telescope. The horizontal steel tube was long. The telescope’s eyepiece/plate end could be shifted five feet on rails for focusing. With the lowest power of 500×, the field of view was 3 arc minutes.
John Beverley Oke
John Beverley Oke (23 March 1928 – 2 March 2004) was an astronomer and professor of astronomy at Caltech. He worked in astronomical photometry and spectroscopy and is well known for creating instruments for the detection and measurement of cosmic phenomena. His instruments were used on the Hale telescope at Mt. Palomar, California and the Keck telescope on Mauna Kea, Hawaii. "He was one of the first really serious and really excellent astronomer-instrumentalists," says James E. Gunn, Eugene Higgins Professor of Astronomy at Princeton University Observatory, "and he and the instruments he designed and built were very largely responsible for keeping Palomar and the 200-inch telescope so far ahead of the rest of the world during the 1960s, 1970s, and 1980s."
Carte du Ciel
For the Astrographic Catalogue, 20 observatories from around the world participated in exposing and measuring more than 22,000 glass plates (see table). Around half of the observatories ordered telescopes from the Henry brothers (Paul and Prosper) in France, with others coming from the factory of Howard Grubb of Dublin. These telescopes were termed "normal astrographs" with an aperture of around 13 inches (33 cm) and a focal length of 11 feet (3.4 m) designed to create images with a uniform scale on the photographic plate of approximately 60 arcsecs/mm while covering a 2° × 2° field of view. Each observatory was assigned a specific declination zone to photograph. The first such plate was taken in August 1891 at the Vatican Observatory (where the exposures took more than 27 years to complete), and the last in December 1950 at the Ukkel Observatory (Brussels), with most observations being made between 1895 and 1920. To compensate for plate defects, each area of the sky was photographed twice, using a two-fold, corner-to-centre overlap pattern, extended at the zone boundaries, such that each observatory's plates would overlap with those of the adjacent zones. The participating observatories agreed to use a standardized telescope so that all plates had a similar scale of approximately 60 arcsec/mm. The measurable areas of the plates were 2.1°×2.1° (13 cm×13 cm), so the overlap pattern consisted of plates that were centred on every degree band in declination, but offset in right ascension by two degrees. Many factors, such as reference catalogue, reduction technique and print formats were left up to the individual institutions. The positional accuracy goal was 0.5 arcsec per image.
Plate measurement was a protracted affair, with measuring done by eye and recorded by hand. The plates were turned over to a large number of semi-skilled "computers" to determine the positions of the stars on each plate. (Before its modern meaning, the word "computer" meant a person who performs calculations). The "computers" would manually measure each star with respect to the dozen or so reference stars within that particular plate, and then perform calculations to determine the star's right ascension and declination. The original goal of 11 mag for the limiting magnitude was generally surpassed, however, with some observatories routinely measuring stars as faint as 13 mag. In total, some 4.6 million stars (8.6 million images) were observed. The brightest stars were over-exposed on the plates, not measured, and therefore missing in the resulting catalogues. The plate measurements (as rectangular coordinates), as well as the formulae to transform them to equatorial coordinates, were published in the original volumes of the Astrographic Catalogue, although the accompanying equatorial coordinates are now of only historical interest. Publication of the measurements proceeded from 1902 to 1964, and resulted in 254 printed volumes of raw data. 
For decades the Astrographic Catalogue was largely ignored. The data were difficult to work with because they were available neither in machine-readable form nor in equatorial coordinates. Decades of labour were expended internationally before the project was superseded by modern astronomical techniques. One problem was that the work took much longer than expected. As originally envisaged, the project was meant to have taken only 10 to 15 years. A more serious problem was that while many European astronomers were preoccupied with this project, which required steady, methodical labor rather than creativity, in other parts of the world notably the United States astrophysics was becoming far more important than astrometry. As a result, French astronomy in particular fell behind and lagged for decades.
Hobby–Eberly Telescope
As reported in "Nature" of 28 November 2012, astronomers have used the Hobby–Eberly Telescope to measure the mass of an extraordinarily large black hole (with mass approximates 17 billion Suns), possibly the largest black hole found so far. It has been found in the compact, lenticular galaxy NGC 1277, which lies 220 million light-years away in the constellation Perseus. The black hole has approximately 59 percent of the mass of the bulge of this spiral galaxy (14 percent of the total stellar mass of the galaxy).
Anglo-Australian Telescope
The telescope was commissioned in 1974 with a view to allowing high quality observations of the sky from the southern hemisphere. At the time, most major telescopes were located in the northern hemisphere, leaving the southern skies poorly observed. It was the largest telescope in the Southern hemisphere from 1974-1976, then a close second to the Victor M. Blanco Telescope from 1976 until 1998, when the first ESO Very Large Telescope (VLT) was opened. The AAT was credited with stimulating a resurgence in British optical astronomy. It was built by the United Kingdom in partnership with Australia but has been entirely funded by Australia since 2010. Observing time is available to astronomers worldwide.
History of the telescope
The beginning of the 20th century saw construction of the first of the "modern" large research reflectors, designed for precision photographic imaging and located at remote high altitude clear sky locations such as the 60-inch Hale telescope of 1908, and the Hooker telescope in 1917, both located at Mount Wilson Observatory. These and other telescopes of this size had to have provisions to allow for the removal of their main mirrors for re-silvering every few months. John Donavan Strong, a young physicist at the California Institute of Technology, developed a technique for coating a mirror with a much longer lasting aluminum coating using thermal vacuum evaporation. In 1932, he became the first person to "aluminize" a mirror; three years later the and telescopes became the first large astronomical telescopes to have their mirrors aluminized. 1948 saw the completion of the Hale reflector at Mount Palomar which was the largest telescope in the world up until the completion of the massive BTA-6 in Russia twenty-seven years later. The Hale reflector introduced several technical innovations used in future telescopes, including hydrostatic bearings for very low friction, the Serrurier truss for equal deflections of the two mirrors as the tube sags under gravity, and the use of Pyrex low-expansion glass for the mirrors. The arrival of substantially larger telescopes had to await the introduction of methods other than the rigidity of glass to maintain the proper shape of the mirror.
Mills Observatory
During the next three years the telescope room was closed to the public while the work proceeded. Only the balcony was available and observations were carried out with small instruments. The telescope was completed in 1950 and described as "the first of its kind in the world." Unfortunately, it was purely for photographic work, which rather contradicted the above assurance.
However, matters took a different course. The expansion of the city north and west and the development of sodium and mercury street-lighting hampered the work of stellar photography, so in February, 1951 Bruce and Professor Freundlich suggested that the pilot telescope be transferred to St. Andrews University Observatory, eleven miles (18 km) to the south, for better conditions and proximity to the workshops. The Mills would then receive in exchange the 10-inch (25 cm.) Cooke refracting telescope formerly used as a student training instrument and now surplus to requirements. At first the Town Council refused, and there was much correspondence in the local press, and indignation among local amateurs, that the University should interfere with the affairs of a public institution. Professor W.H.M. Greaves, had succeeded Professor Sampson as Astronomer Royal for Scotland, was called upon to advise on the matter. In view of the scientific benefits of the move, and lack of interest shown by University College, Dundee, he recommended that the transfer take place. This was done at the University's expense, and on the understanding that the two telescopes were on mutual loan.
John Adams Whipple
Between 1847 and 1852 Whipple and astronomer William Cranch Bond, director of the Harvard College Observatory, used Harvard's Great Refractor telescope to produce images of the moon that are remarkable in their clarity of detail and aesthetic power. This was the largest telescope in the world at that time, and their images of the moon took the prize for technical excellence in photography at the great 1851 Crystal Palace Exhibition in London.
Hard X-ray Modulation Telescope
Hard X-ray Modulation Telescope (HXMT) also known as Insight () is a Chinese X-ray space observatory, launched on June 15, 2017 to observe black holes, neutron stars, active galactic nuclei and other phenomena based on their X-ray and gamma-ray emissions. It is based on the JianBing 3 imagery reconnaissance satellite series platform.
Telescope (goldfish)
The black telescope is a black colored variant of a telescope goldfish that has a characteristic pair of protruding eyes. Black telescopes are commonly known as Blackamoors, black moors or just moors, a reference to the black North African Muslim inhabitants of Al-Andalus.
Transient astronomical event
Before the invention of telescopes, events such as these that were visible to the naked eye, from within or near the Milky Way Galaxy, were very rare, and sometimes hundreds of years apart. However, such events were recorded in antiquity, such as the supernova in 1054 observed by Chinese, Japanese and Arab astronomers, and the event in 1572 known as "Tycho's Supernova" after Tycho Brahe, who studied it until it faded after two years. Even though telescopes made it possible to see more distant events, their small fields of view – typically less than 1 square degree – meant that the chances of looking in the right place at the right time were low. Schmidt cameras and other astrographs with wide field were invented in the 20th century, but mostly used to survey the unchanging heavens.
United States Naval Observatory Flagstaff Station
The Kaj Strand Telescope (or Kaj Strand Astrometric Reflector, "KSAR") remains largest telescope operated by the U.S. Navy. Congress appropriated funding in 1961 and it saw first light in 1964. This status will change when the NPOI four 1.8-meter telescopes see their own first light in the near future. KSAR rides in the arms of an equatorial fork mount. The telescope is used in both the visible spectrum, and in the near infrared (NIR), the latter using a sub-30-kelvin, helium-refrigerated, InSb (Indium antimonide) camera, "Astrocam". In 1978, the 1.55-m telescope was used to "discover the moon of dwarf planet Pluto, named 'Charon'". (Pluto itself was discovered in 1930, across town at Lowell Observatory). The Charon discovery led to mass calculations which ultimately revealed how tiny Pluto was, and eventually caused the IAU to reclassify Pluto as a dwarf (not a principle) planet. The 1.55-meter telescope was also used to observe and track NASA's Deep Impact Spacecraft, as it navigated to a successful inter-planetary impact with the celebrated Comet 9p/Tempel, in 2005. This telescope is particularly well-suited to perform stellar parallax studies, narrow-field astrometry supporting space navigation, and has also played a key role in discovering one of the coolest-ever known brown dwarf objects, in 2002. The KSAR dome is centrally located on NOFS grounds, with support and office buildings attached to the dome structures. The large vacuum coating chamber facility is also located in this complex. The chamber can provide very accurate coatings and overcoatings of Angstrom thickness (approximately 56 aluminium atoms thick), for small-to-multi-ton optics up to in diameter, in a vacuum exceeding , using a vertical-optic, 1500-ampere discharge system. A dielectric coating capability has also been demonstrated. Large optics and telescope components can be moved about NOFS using its suite of cranes, lifts, cargo elevators and specialized carts. The main complex also contains a controlled-environment, optical and electronics lab for laser, adaptive optics, optics development, collimation, mechanical, and micro-electronic control systems needed for NOFS and NPOI.
Goode Solar Telescope
The Goode Solar Telescope (GST) is a scientific facility for studies of the Sun named after Philip R. Goode.
It is the solar telescope with the world's largest aperture in operation. Located in Big Bear Lake; California, the Goode Solar Telescope is the main telescope of the Big Bear Solar Observatory operated by the New Jersey Institute of Technology (NJIT). Initially named New Solar Telescope (NST), first engineering light was obtained in December 2008, and scientific observations of the Sun began in January 2009. On July 17, 2017, the NST was renamed in honor of Goode, a former, and founding director of NJIT's Center for Solar-Terrestrial Research and the principal investigator of the facility. Goode conceived, raised the funds, and assembled the team that built and commissioned the telescope, which is the highest resolution solar telescope in the world and the first facility class solar telescope built in the U.S. in a generation.
Fenton Hill Observatory
The RAPTOR system (Rapid Telescopes for Optical Response) is a specialized suite of telescopes designed to detect and track transient objects, including gamma-ray bursts and near-earth objects. RAPTOR was built by a Los Alamos team headed by astrophysicist Tom Vestrand. The system consists of six robotic observatories—RAPTOR-A, -S, -P, -K, and -T are located at Fenton Hill and RAPTOR-B is located at the Los Alamos Neutron Science Center, away. The telescopes are all networked and controlled by a centralized computer system. The older RAPTOR telescopes, RAPTORs A, B, S and P each consist of a wide-field telescope and a narrow-field telescope. They are mounted on platforms that can swivel to any point in the sky in less than 3 seconds, making them the fastest moving telescopes ever built. Each wide-field telescope has a nominal field of view of 38 by 38 degrees, which equates to being able to cover the sky in eleven patches. Each telescope is actually two telescopes giving stereoscopic vision. There is a zoom mechanism built into each telescope as well. While in monitoring mode, RAPTOR takes two consecutive 30-second exposures through its two wide-field telescopes and analyzes the resulting digital images. If it sees an interesting event, RAPTOR zooms in for a closer look with the two narrow-field telescopes.
Apache Point Observatory
The ARC Small Aperture Telescope (ARCSAT) was previously called the Photometric Telescope (PT) when it was part of the SDSS project. It is a reflecting telescope on an equatorial mount, with a single CCD camera cooled by a CryoTiger unit. It was built in 1991, moved from its previous location in 1998, and used by the SDSS until 2005. It is currently used for small research projects.The Minor Planet Center credits the discovery of the following minor planets directly to the Apache Point Observatory:
Killarney Provincial Park Observatory
The light gathering ability of a 16" telescope coupled with Meade's "Advanced Come-Free" design in a Dark-Sky Preserve provides exceptional astrophotographic capability. On July 9, the telescope was aligned to better enable long duration astrophotography. Using today's stacking technology and cooled CCD cameras will yield outstanding results. Initial DSLR photography was obtained to demonstrate the capability of single image, "thumb-on-the-shutter" exposures. All the images (below) were taken with the primary (16") or secondary (130mm) telescopes.
Camera Obscura, Edinburgh
In the early 18th century, the Edinburgh instrument maker Thomas Short leased some land on Calton Hill to display his instruments to the public. As his lease stipulated female relatives of Thomas could not inherit the building and its contents, his wife and children did not inherit it when he died in 1788. In 1827, Maria Theresa Short returned to Edinburgh from the West Indies claiming to be Thomas Short’s daughter and attempted to claim his "Great Telescope" for her inheritance. Despite strong competition from other parties, she received the telescope and set up "Short's Popular Observatory" in 1835, housed in a wooden and stone building next to the National Monument on Calton Hill. She exhibited many scientific instruments and kept her Observatory open till 9pm each evening.
Major Atmospheric Cerenkov Experiment Telescope
The telescope is named after the Soviet scientist Pavel Cherenkov, who predicted that charged particles moving at high speeds in a medium emit light. The high-energy gamma rays emitted from black holes, centers of galaxies and pulsars do not reach the land as they get absorbed in the atmosphere. Upon interaction with the atmosphere, these photons produce electron–positron pairs, leading to a cascade of particles which while moving at very high speed give rise to Cerenkov radiation.