When was the first telescope invented?
Sidereus Nuncius
The first telescopes appeared in the Netherlands in 1608 when Middelburg spectacle-maker Hans Lippershey tried to obtain a patent on one. By 1609 Galileo had heard about it and built his own improved version. He probably was not the first person to aim the new invention at the night sky but his was the first systematic (and published) study of celestial bodies using one. One of Galileo's first telescopes had 8x to 10x linear magnification and was made out of lenses that he had ground himself. This was increased to 20x linear magnification in the improved telescope he used to make the observations in "Sidereus Nuncius".
Graphic telescope
The graphic telescope is a type of camera lucida that has the power of a telescope. It was invented by Cornelius Varley in 1811.
Teleidoscope
A teleidoscope is a kind of kaleidoscope, with a lens and an open view, so it can be used to form kaleidoscopic patterns from objects outside the instrument, rather than from items installed as part of it. Invented by John Lyon Burnside III and Harry Hay, the patent was filed in 1970 and granted in 1972.
Thermoscope
It is thought, but not certain that Galileo Galilei discovered the specific principle on which the device is based and built the first thermoscope in 1593. Galileo mentioned to his friend Cesare Marsili that he invented a thermoscope as far back as 1606. The inventor could be his physician friend Santorio Santorio or another person of the learned circle in Venice of which they were members. What is certain is that the thermoscope has started circulating in market squares during Galileo's time. The development of the actual device is attributed to four inventors namely, Galileo, Santorio Santorio, Robert Fludd, and Cornelius Drebbel. However, the general pneumatic principle of the thermoscope was used in the Hellenic period, and it was written about even earlier, by Empedocles of Agrigentum in his 460 B.C. book "On Nature".
Clock drive
Different types of equatorial clock-driven telescopes were built or proposed in the 17th and 18th century including English astronomer Robert Hooke's 1674 paper proposing their use in precision measurement, a clock-driven aerial telescope objective lens constructed in 1685 by Italian-French astronomer Giovanni Domenico Cassini fitted with setting circles, and one supposedly built by English clockmaker and inventor George Graham early 18th century.
What is considered the first practical clock-driven telescope was constructed in 1824, Joseph von Fraunhofer's ‘Great Dorpat’ refractor, a telescope that combined other innovations, such as an achromatic lens and Fraunhofer's "German equatorial mount", making it the prototype of all future large refracting telescopes. Early telescope clock drives used a clock work with falling weights and pendulums, almost like grandfather clocks. Over time the falling weights and pendulums were replaced by an electric motor.
Mount Wilson Observatory
The Snow Solar Telescope was the first telescope installed at the fledgling Mount Wilson Solar Observatory. It was the world's first permanently mounted solar telescope. Solar telescopes had previously been portable so they could be taken to solar eclipses around the world. The telescope was donated to Yerkes Observatory by Helen Snow of Chicago. George Ellery Hale, then director of Yerkes, had the telescope brought to Mount Wilson to put it into service as a proper scientific instrument. Its primary mirror with a focal length, coupled with a spectrograph, did groundbreaking work on the spectra of sunspots, doppler shift of the rotating solar disc and daily solar images in several wavelengths. Stellar research soon followed as the brightest stars could have their spectra recorded with very long exposures on glass plates. Today the Snow solar telescope is mostly used by undergraduate students who get hands on training in solar physics and spectroscopy.
It was also used publicly for the May 9, 2016 transit of Mercury across the face of the sun.
History of the telescope
Hall was a man of independent means and seems to have been careless of fame; at least he took no trouble to communicate his invention to the world. At a trial in Westminster Hall about the patent rights granted to John Dollond (Watkin v. Dollond), Hall was admitted to be the first inventor of the achromatic telescope. However, it was ruled by Lord Mansfield that it was not the original inventor who ought to profit from such invention, but the one who brought it forth for the benefit of mankind.
History of the telescope
The first person who succeeded in making a practical achromatic refracting telescope was Chester Moore Hall from Essex, England. He argued that the different humours of the human eye refract rays of light to produce an image on the retina which is free from color, and he reasonably argued that it might be possible to produce a like result by combining lenses composed of different refracting media. After devoting some time to the inquiry he found that by combining two lenses formed of different kinds of glass, he could make an achromatic lens where the effects of the unequal refractions of two colors of light (red and blue) was corrected. In 1733, he succeeded in constructing telescope lenses which exhibited much reduced chromatic aberration. One of his instruments had an objective measuring with a relatively short focal length of .
Reber Radio Telescope
The telescope was built by astronomer Grote Reber in his back yard in Wheaton, Illinois in 1937, following up on the research of Karl Jansky, the discoverer (in 1931) of radio waves emanating from the Milky Way. It was the second radio telescope ever built (after Jansky's dipole array), and the first parabolic radio telescope, serving as a prototype for the first large dish radio telescopes such as the Green Bank Telescope and Lovell Telescope constructed after World War 2. Reber was the world's only radio astronomer at the time, and his construction of the telescope and the sky surveys he did with it helped found the field of radio astronomy, revealing radio sources such as Cassiopeia A and Cygnus X-1 for the first time.
Newton's reflector
Newton's third telescope was built in 1671-1672 by Newton and his "chamber fellow" at Trinity College John Wickins. He reported that Wickins did a better job of figuring the mirror than he had done on his second telescope. This is the telescope that he had by him when he was writing Opticks. The telescope appeared some time later in the shop of Heath and Wing instrument makers along with an instrument of Newtons belonging to Edmond Halley. It is most likely that the telescope had passed to Halley and then to Heath and Wing. This third telescope had the mirror damaged in 1694 by Newton while trying to clean it. It is thought that the mirror was later refigured by restorers accounting for its plugged eyepiece hole at an appropriate distance for a 6.25 inch focal length mirror and the new eyepiece position for the current mirror focal length of 8.5 inches. The current brass eyepiece is not original and was added later. This telescope was restored by Heath and Wing and presented to the Royal Society in 1766 as the telescope that Newton had made. At a later date a plaque was added to this telescope with the incorrect inscription claiming that it was his first telescope and made in 1671. This telescope probably includes the original mirrors, reground, part of the original base, the original support bar and possibly the original tube or parts of it.
La Silla Observatory
By 1976, the largest telescope planned, the , started operations. It was subsequently to have a 1.4m CAT (Coudé Auxiliary Telescope) attached. In 1984, the 2.2m telescope began operations, while in March 1989, the 3.5 m New Technology Telescope (NTT) saw first light. The program reached its apex with the installation of the SEST in 1987 (Swedish ESO Submillimetre Telescope), the only large submillimetre telescope in the southern hemisphere, which was a combined project between ESO and the Swedish Natural Science Research Council. Around the end of the century some of the original telescopes were closed: the 1m Schmidt closed in 1998 and the 1.5m in 2002, while new equipment owned by various foreign observatories was introduced. A 1-metre telescope owned by Marseille Observatory opened in 1998, followed by a 1.2-metre telescope from Geneva Observatory in 2000.
Optical telescope
For reflecting telescopes, which use a curved mirror in place of the objective lens, theory preceded practice. The theoretical basis for curved mirrors behaving similar to lenses was probably established by Alhazen, whose theories had been widely disseminated in Latin translations of his work. Soon after the invention of the refracting telescope Galileo, Giovanni Francesco Sagredo, and others, spurred on by their knowledge that curved mirrors had similar properties as lenses, discussed the idea of building a telescope using a mirror as the image forming objective. The potential advantages of using parabolic mirrors (primarily a reduction of spherical aberration with elimination of chromatic aberration) led to several proposed designs for reflecting telescopes, the most notable of which was published in 1663 by James Gregory and came to be called the Gregorian telescope, but no working models were built. Isaac Newton has been generally credited with constructing the first practical reflecting telescopes, the Newtonian telescope, in 1668 although due to their difficulty of construction and the poor performance of the speculum metal mirrors used it took over 100 years for reflectors to become popular. Many of the advances in reflecting telescopes included the perfection of parabolic mirror fabrication in the 18th century, silver coated glass mirrors in the 19th century, long-lasting aluminum coatings in the 20th century, segmented mirrors to allow larger diameters, and active optics to compensate for gravitational deformation. A mid-20th century innovation was catadioptric telescopes such as the Schmidt camera, which uses both a lens (corrector plate) and mirror as primary optical elements, mainly used for wide field imaging without spherical aberration.
History of the telescope
In 1682, the minutes of the Royal Society in London Robert Hooke noted Thomas Digges' 1571 "Pantometria", (a book on measurement, partially based on his father Leonard Digges' notes and observations) seemed to support an English claim to the invention of the telescope, describing Leonard as having a "fare seeing glass" in the mid 1500s based on an idea by Roger Bacon. Thomas described it as ""by proportional Glasses duly situate in convenient angles, not only discovered things far off, read letters, numbered pieces of money with the very coin and superscription thereof, cast by some of his friends of purpose upon downs in open fields, but also seven miles off declared what hath been done at that instant in private places"." Comments on the use of proportional or "perspective glass" are also made in the writings of John Dee (1575) and William Bourne (1585). Bourne was asked in 1580 to investigate the Diggs device by Queen Elizabeth I's chief advisor Lord Burghley. Bourne's is the best description of it, and from his writing it seemed to consist of peering into a large curved mirror that reflected the image produced by a large lens. The idea of an "Elizabethan Telescope" has been expanded over the years, including astronomer and historian Colin Ronan concluding in the 1990s that this reflecting/refracting telescope was built by Leonard Digges between 1540 and 1559. This "backwards" reflecting telescope would have been unwieldy, it needed very large mirrors and lens to work, the observer had to stand backwards to look at an upside down view, and Bourne noted it had a very narrow field of view making it unsuitable for military purposes. The optical performance required to see the details of coins lying about in fields, or private activities seven miles away, seems to be far beyond the technology of the time and it could be the "perspective glass" being described was a far simpler idea, originating with Bacon, of using a single lens held in front of the eye to magnify a distant view.
Experimental psychology
The first stereoscope was invented by Wheatstone in 1838. It presents two slightly different images, one to each eye, at the same time. Typically the images are photographs of the same object taken from camera positions that mimic the position and separation of the eyes in the head. When one looks through the steroscope the photos fuse into a single image that conveys a powerful sense of depth and solidity.
Telescopium
Telescopium is a minor constellation in the southern celestial hemisphere, one of twelve named in the 18th century by French astronomer Nicolas-Louis de Lacaille and one of several depicting scientific instruments. Its name is a Latinized form of the Greek word for telescope. Telescopium was later much reduced in size by Francis Baily and Benjamin Gould.
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.
Leibniz Institute for Astrophysics Potsdam
The first new instruments were delivered in the spring of 1914. The 65 cm refractor — the first big astronomical instrument manufactured by the famous enterprise of Carl Zeiss Jena — was mounted in 1915, whereas the completion of the 122 cm reflector telescope was delayed until 1924 by the First World War. Struve died in 1920 from an accident, and his successor was Paul Guthnick, who introduced in 1913 photoelectric photometry into astronomy as the first objective method of measuring the brightness of stars. When the 122 cm telescope (at this time the second largest in the world) was finished, the Babelsberg Observatory was the best-equipped observatory of Europe.
Newton's reflector
There has been much confusion and dispute concerning the telescopes that Newton built, but it is now clear that his first telescope was a prototype that he constructed in 1668. This was seen only by a few friends at Cambridge and very little is known of it. This prototype had a mirror a little over an inch in diameter, probably 1.3 inches, and around 6 inches in length. Newton seldom referred to this prototype in later years and so his second scope is often called his first.
Portobello, Dublin
Thomas Grubb (1800–1878), a notable optician, developed his first telescope in a small house between Portobello Bridge and Charlemont Bridge and erected a public observatory at No. 1 Upper Charlemont Street. He founded the Grubb Telescope Company. One of his earliest instruments – the telescope for Markree Observatory in County Sligo – was, for several years, the largest telescope in the world. They provided the telescopes for many observatories worldwide, including Melbourne, Vienna and Aldershot Observatory in 1891. The company was acquired in 1925 by Charles Algernon Parsons and renamed Sir Howard Grubb, Parsons and Co. Ltd.
History of the telescope
The British mathematician, optician James Short began experimenting with building telescopes based on Gregory's designs in the 1730s. He first tried making his mirrors out of glass as suggested by Gregory, but he later switched to speculum metal mirrors creating Gregorian telescopes with original designers parabolic and elliptic figures. Short then adopted telescope-making as his profession which he practised first in Edinburgh, and afterward in London. All Short's telescopes were of the Gregorian form. Short died in London in 1768, having made a considerable fortune selling telescopes.
Telemeter
In 1781 Georg Friedrich Brander invented the coincidence telemeter. Two mirrors set a distance apart horizontally and forming two images in the same eyepiece. This rangefinder does not require a measuring rod at the target and could perhaps be considered the first true telemeter. In 1790 Jesse Ramsden invented a half-image range finder. In 1899 Carl Pulfrich at Carl Zeiss AG invented the stereo telemeter.
Electroscope
An electroscope is a scientific instrument used to detect the presence and magnitude of electric charge on a body. It was the first electrical measuring instrument. The first electroscope, a pivoted needle called the "versorium", was invented by British physician William Gilbert around 1600. The pith-ball electroscope and the gold-leaf electroscope are two classical types of electroscope that are still used in physics education to demonstrate the principles of electrostatics. A type of electroscope is also used in the quartz fiber radiation dosimeter. Electroscopes were used by the Austrian scientist Victor Hess in the discovery of cosmic rays.
Bayfordbury Observatory
The first telescope, a 16-inch Newtonian/Cassegrain telescope, was built on the site in 1969, one year after astronomy was first taught at the Hatfield Polytechnic. In 1970 the observatory was formally opened by Richard van der Riet Woolley, then Astronomer Royal.
Over the years the number of telescopes has increased along with the size of astronomy department.
Observatory Naef Épendes
The invention of the telescope in 1608 and the subsequent improvements in optics led to the revolutionary progress of the 17th and 18th centuries. We call this type of telescope a refractor because it deviates the light coming from an object in such a way that its image is reversed ; observation is done through an eyepiece at the end of the tube, which allows magnification of the image. Bequeathed by Mr. Robert A. Naef, the observatory's precious telescope is a Reinfelder & Hertel with a diameter of 162.5 mm and a focal distance of 1435 mm - this allows a magnification of X150.
Optical microscope
Galileo Galilei is also sometimes cited as a compound microscope inventor. After 1610 he found that he could close focus his telescope to view small objects, such as flies, close up and/or could look through the wrong end in reverse to magnify small objects. The only drawback was that his 2 foot long telescope had to be extended out to 6 feet to view objects that close. After seeing the compound microscope built by Drebbel exhibited in Rome in 1624, Galileo built his own improved version. In 1625 Giovanni Faber coined the name "microscope" for the compound microscope Galileo submitted to the Accademia dei Lincei in 1624 (Galileo had called it the ""occhiolino"" or ""little eye""). Faber coined the name from the Greek words "μικρόν" (micron) meaning "small", and "σκοπεῖν" (skopein) meaning "to look at", a name meant to be analogous with "telescope", another word coined by the Linceans.
History of the telescope
The first record of a telescope comes from the Netherlands in 1608. It is in a patent filed by Middelburg spectacle-maker Hans Lippershey with the States General of the Netherlands on 2 October 1608 for his instrument ""for seeing things far away as if they were nearby"". A few weeks later another Dutch instrument-maker, Jacob Metius also applied for a patent. The States General did not award a patent since the knowledge of the device already seemed to be ubiquitous but the Dutch government awarded Lippershey with a contract for copies of his design.
Radio telescope
Radio waves from space were first detected by engineer Karl Guthe Jansky in 1932 at Bell Telephone Laboratories in Holmdel, New Jersey using an antenna built to study noise in radio receivers. The first purpose-built radio telescope was a 9-meter parabolic dish constructed by radio amateur Grote Reber in his back yard in Wheaton, Illinois in 1937. The sky survey he did with it is often considered the beginning of the field of radio astronomy.
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.
Reflecting telescope
Isaac Newton has been generally credited with building the first reflecting telescope in 1668. It used a spherically ground metal primary mirror and a small diagonal mirror in an optical configuration that has come to be known as the Newtonian telescope.
Craig telescope
It was the largest refracting telescope (a telescope with a lens) in the world from 1852 to 1857, erected near London, England. It was a great refractor, a large refracting telescope with an achromatic doublet with an aperture of 61 cm (2 feet (24 inches)) and that was completed in 1852 in Wandsworth Common and dismantled around 1857 (although the brick tower probably survived until 1870). It had a focal length of 76–83 feet. Its namesake, the Rev. John Craig, spent a small fortune to produce a uniquely designed telescope with nearly double the aperture of the next largest refracting telescopes, making it the largest refracting telescope in the World for the better part of a decade. However, it had problem with its lens figuring starting from its first light in the summer of 1852. It soon fell into disuse as that same year Craig lost his only son, then his wife in 1854, and lost his brother and was put in jail for 6 weeks in 1856.
William Herschel
Reflector telescopes, invented by Isaac Newton in 1668, used a single concave mirror rather than a convex lens. The concave mirror gathered more light than a lens, reflecting it onto a flat mirror at the end of the telescope for viewing. A smaller mirror could provide greater magnification and a larger field of view than a convex lens. Newton's first mirror was 1.3 inches in diameter; such mirrors were rarely more than 3 inches in diameter.
Palomar Observatory
The 200-inch telescope was the largest telescope in the world from 1949 until 1975, when the Russian BTA-6 telescope saw first light. Astronomers using the Hale Telescope have discovered distant objects at the edges of the known universe called quasars and have given us the first direct evidence of stars in distant galaxies. They have studied the structure and chemistry of intergalactic clouds, leading to an understanding of the synthesis of elements in the universe, and have discovered thousands of asteroids. A one-tenth-scale engineering model of the telescope at Corning Community College in Corning, New York, home of the Corning Glass Works (now Corning Incorporated) was used to discover at least one minor planet, 34419 Corning.
Reflecting telescope
The idea that curved mirrors behave like lenses dates back at least to Alhazen's 11th century treatise on optics, works that had been widely disseminated in Latin translations in early modern Europe. Soon after the invention of the refracting telescope, Galileo, Giovanni Francesco Sagredo, and others, spurred on by their knowledge of the principles of curved mirrors, discussed the idea of building a telescope using a mirror as the image forming objective. There were reports that the Bolognese Cesare Caravaggi had constructed one around 1626 and the Italian professor Niccolò Zucchi, in a later work, wrote that he had experimented with a concave bronze mirror in 1616, but said it did not produce a satisfactory image. The potential advantages of using parabolic mirrors, primarily reduction of spherical aberration with no chromatic aberration, led to many proposed designs for reflecting telescopes. The most notable being James Gregory, who published an innovative design for a ‘reflecting’ telescope in 1663. It would be ten years (1673), before the experimental scientist Robert Hooke was able to build this type of telescope, which became known as the Gregorian telescope.
History of the telescope
The era of radio telescopes (along with radio astronomy) was born with Karl Guthe Jansky's serendipitous discovery of an astronomical radio source in 1931. Many types of telescopes were developed in the 20th century for a wide range of wavelengths from radio to gamma-rays. The development of space observatories after 1960 allowed access
to several bands impossible to observe from the ground, including X-rays and longer wavelength infrared bands.
History of the telescope
From the time of the invention of the first refracting telescopes it was generally supposed that chromatic errors seen in lenses simply arose from errors in the spherical figure of their surfaces. Opticians tried to construct lenses of varying forms of curvature to correct these errors. Isaac Newton discovered in 1666 that chromatic colors actually arose from the un-even refraction of light as it passed through the glass medium. This led opticians to experiment with lenses constructed of more than one type of glass in an attempt to canceling the errors produced by each type of glass. It was hoped that this would create an "achromatic lens"; a lens that would focus all colors to a single point, and produce instruments of much shorter focal length.
Reflecting telescope
A reflecting telescope (also called a reflector) is a telescope that uses a single or a combination of curved mirrors that reflect light and form an image. The reflecting telescope was invented in the 17th century, by Isaac Newton, as an alternative to the refracting telescope which, at that time, was a design that suffered from severe chromatic aberration. Although reflecting telescopes produce other types of optical aberrations, it is a design that allows for very large diameter objectives. Almost all of the major telescopes used in astronomy research are reflectors. Reflecting telescopes come in many design variations and may employ extra optical elements to improve image quality or place the image in a mechanically advantageous position. Since reflecting telescopes use mirrors, the design is sometimes referred to as a "catoptric" telescope.
History of the telescope
In 1995 this imaging technique was demonstrated on an array of separate optical telescopes for the first time, allowing a further improvement in resolution, and also allowing even higher resolution imaging of stellar surfaces. The same techniques have now been applied at a number of other astronomical telescope arrays including: the Navy Prototype Optical Interferometer, the CHARA array, and the IOTA array. A detailed description of the development of astronomical optical interferometry can be found here [https://www.webcitation.org/5kmngkBFy?url=http://www.geocities.com/CapeCanaveral/2309/page1.html
History of the telescope
Actual use of lenses dates back to the widespread manufacture and use of eyeglasses in Northern Italy beginning in the late 13th century. The invention of the use of concave lenses to correct near-sightedness is ascribed to Nicholas of Cusa in 1451.
Timeline of astronomy
The 10 meter Keck telescope on Mauna Kea, Hawaii, is completed. The first revolutionary new wave of telescopes, the Keck's main mirror is made of 36 six-sided segments, with computers to control their alignment. New optical telescopes also make use of interferometry – improving resolution by combining images from separate telescopes.
History of the telescope
The ability of a curved mirror to form an image may have been known since the time of Euclid and had been extensively studied by Alhazen in the 11th century. Galileo, Giovanni Francesco Sagredo, and others, spurred on by their knowledge that curved mirrors had similar properties to lenses, discussed the idea of building a telescope using a mirror as the image forming objective. Niccolò Zucchi, an Italian Jesuit astronomer and physicist, wrote in his book "Optica philosophia" of 1652 that he tried replacing the lens of a refracting telescope with a bronze concave mirror in 1616. Zucchi tried looking into the mirror with a hand held concave lens but did not get a satisfactory image, possibly due to the poor quality of the mirror, the angle it was tilted at, or the fact that his head partially obstructed the image.
History of the telescope
William Gascoigne was the first who commanded a chief advantage of the form of telescope suggested by Kepler: that a small material object could be placed at the common focal plane of the objective and the eyepiece. This led to his invention of the micrometer, and his application of telescopic sights to precision astronomical instruments. It was not till about the middle of the 17th century that Kepler's telescope came into general use: not so much because of the advantages pointed out by Gascoigne, but because its field of view was much larger than in the Galilean telescope.
Refracting telescope
The achromatic refracting lens was invented in 1733 by an English barrister named Chester Moore Hall, although it was independently invented and patented by John Dollond around 1758. The design overcame the need for very long focal lengths in refracting telescopes by using an objective made of two pieces of glass with different dispersion, 'crown' and 'flint glass', to limit the effects of chromatic and spherical aberration. Each side of each piece is ground and polished, and then the two pieces are assembled together. Achromatic lenses are corrected to bring two wavelengths (typically red and blue) into focus in the same plane. The era of the 'great refractors' in the 19th century saw large achromatic lenses culminating with the largest achromatic refractor ever built, the Great Paris Exhibition Telescope of 1900.
History of the telescope
Johannes Kepler first explained the theory and some of the practical advantages of a telescope constructed of two convex lenses in his "Catoptrics" (1611). The first person who actually constructed a telescope of this form was the Jesuit Christoph Scheiner who gives a description of it in his "Rosa Ursina" (1630).
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.
Thomas Harriot
Halley's Comet in 1607 turned Harriot's attention towards astronomy. In early 1609 he bought a "Dutch trunke" (telescope), invented in 1608, and his observations were among the first uses of a telescope for astronomy. Harriot is now credited as the first astronomer to draw an astronomical object after viewing it through a telescope: he drew a map of the Moon on 26 July 1609, preceding Galileo by several months. He also observed sunspots in December 1610.
Poland
In the 19th century, throughout partitioned Poland, numerous amateur inventors, such as Kazimierz Prószyński, were eager to construct a film projector. In 1894, Prószyński was successful in creating a Pleograph, one of the first cameras in the world. The invention, which took photographs and projected pictures, was built before the Lumière brothers lodged their patent. He also patented an Aeroscope, the first successful hand-held operated film camera. In 1897, Jan Szczepanik, obtained a British patent for his Telectroscope. This prototype of television could easily transmit image and sound, thus allowing a live remote view. Following the invention of appropriate apparatus and technological development in the upcoming years, his then-impossible concept became reality.
Rangaku
Japan’s first telescope was offered by the English captain John Saris to Tokugawa Ieyasu in 1614, with the assistance of William Adams, during Saris's mission to open trade between England and Japan. This followed the invention of the telescope by Dutchman Hans Lippershey in 1608 by a mere six years. Refracting telescopes were widely used by the populace during the Edo period, both for pleasure and for the observation of the stars.
Ming dynasty
Compared to the flourishing of science and technology in the Song dynasty, the Ming dynasty perhaps saw fewer advancements in science and technology compared to the pace of discovery in the Western world. In fact, key advances in Chinese science in the late Ming were spurred by contact with Europe. In 1626 Johann Adam Schall von Bell wrote the first Chinese treatise on the telescope, the "Yuanjingshuo" ("Far Seeing Optic Glass"); in 1634 the Chongzhen Emperor acquired the telescope of the late Johann Schreck (1576–1630). The heliocentric model of the solar system was rejected by the Catholic missionaries in China, but Johannes Kepler and Galileo Galilei's ideas slowly trickled into China starting with the Polish Jesuit Michael Boym (1612–59) in 1627, Adam Schall von Bell's treatise in 1640, and finally Joseph Edkins, Alex Wylie, and John Fryer in the 19th century. Catholic Jesuits in China would promote Copernican theory at court, yet at the same time embrace the Ptolemaic system in their writing; it was not until 1865 that Catholic missionaries in China sponsored the heliocentric model as their Protestant peers did. Although Shen Kuo (1031–95) and Guo Shoujing (1231–1316) had laid the basis for trigonometry in China, another important work in Chinese trigonometry would not be published again until 1607 with the efforts of Xu Guangqi and Matteo Ricci. Ironically, some inventions which had their origins in ancient China were reintroduced to China from Europe during the late Ming; for example, the field mill.
Cornelis Drebbel
One of the optical devices some historians believe Drebbel invented when he was working for the Duke of Buckingham was the compound microscope. The device appeared in Europe around 1620 with the earliest account being Dutch Ambassador Willem Boreel's 1619 visit to London where he saw a compound microscope in Drebbel's possession, described as an instrument about eighteen inches long, two inches in diameter, and supported on 3 brass dolphins. In 1621 Drebbel had a compound microscope with two convex lenses. Several of his contemporaries, including Christiaan Huygens, credited the invention of the compound microscope to Drebbel. The invention has many counter claims including Dutch spectacle-maker Johannes Zachariassen's claim that Drebbel stole the idea from him and his father, Zacharias Jansen, and claims that Galileo Galilei used his telescope after 1610 as a type of compound microscope. In 1624 Galileo saw Drebbel's design for a microscope in Rome and created an improved version of it to send to Federico Cesi, founder of the Accademia dei Lincei, who used it to illustrate "Apiarum", his book about bees.
History of the telescope
The next major development came in 1946 when Ryle and Vonberg (Ryle and Vonberg 1946) located a number of new cosmic radio sources by constructing a radio analogue of the Michelson interferometer. The signals from two radio antennas were added electronically to produce interference. Ryle and Vonberg's telescope used the rotation of the Earth to scan the sky in one dimension. With the development of larger arrays and of computers which could rapidly perform the necessary Fourier transforms, the first aperture synthesis imaging instruments were soon developed which could obtain high resolution images without the need of a giant parabolic reflector to perform the Fourier transform. This technique is now used in most radio astronomy observations. Radio astronomers soon developed the mathematical methods to perform aperture synthesis Fourier imaging using much larger arrays of telescopes —often spread across more than one continent. In the 1980s, the aperture synthesis technique was extended to visible light as well as infrared astronomy, providing the first very high resolution optical and infrared images of nearby stars.
Vainu Bappu Observatory
The first telescope was of 38 cm (15-inch) aperture, with which astronomical observations were started in 1968 at Kavalur Observatory. The 75 cm (30-inch) telescope has been completely designed and fabricated at the workshops of the Indian Institute of Astrophysics. In 1972 a 1-metre (40-inch) telescope made by Carl Zeiss Jena was installed at Kavalur.
History of the telescope
In 1655 Dutch diplomat William de Boreel tried to solve the mystery of who invented the telescope. He had a local magistrate in Middelburg follow up on Boreel's childhood and early adult recollections of a spectacle maker named "Hans" who he remembered as the inventor of the telescope. The magistrate was contacted by a then unknown claimant, Middelburg spectacle maker Johannes Zachariassen, who testified that his father, Zacharias Janssen invented the telescope and the microscope as early as 1590. This testimony seemed convincing to Boreel, who now recollected that Zacharias and his father, Hans Martens, must have been who he remembered. Boreel's conclusion that Zacharias Janssen invented the telescope a little ahead of another spectacle maker, Hans Lippershey, was adopted by Pierre Borel in his 1656 book "De vero telescopii inventore". Discrepancies in Boreel's investigation and Zachariassen's testimony (including Zachariassen misrepresenting his date of birth and role in the invention) has led some historians to consider this claim dubious. The "Janssen" claim would continue over the years and be added on to with Zacharias Snijder in 1841 presenting 4 iron tubes with lenses in them claimed to be 1590 examples of Janssen's telescope and historian Cornelis de Waard's 1906 claim that the man who tried to sell a broken telescope to astronomer Simon Marius at the 1608 Frankfurt Book Fair must have been Janssen.
Warner &amp; Swasey Company
The first Warner & Swasey telescope, built in 1881, was sold to Beloit College for its new Smith Observatory and had a 9.5-inch lens made by Alvan Clark & Sons. Among the notable instruments the company built were the telescopes for Lick Observatory (1888, 36-inch, refracting); the United States Naval Observatory (1893); Yerkes Observatory (according to the 50th-anniversary book, this was a 40-inch refracting telescope completed in time for display at the World's Columbian Exposition of 1893, although its installation at Yerkes was apparently in 1897); and Canada's Dominion Astrophysical Observatory (1916, 72-inch, reflecting). In 1919, the company's founders donated their private observatory in East Cleveland, Ohio to Case Western Reserve University. Today's Warner and Swasey Observatory grew from that facility.
Radio telescope
An amateur radio operator, Grote Reber, was one of the pioneers of what became known as radio astronomy. He built the first parabolic "dish" radio telescope, in diameter, in his back yard in Wheaton, Illinois in 1937. He repeated Jansky's pioneering work, identifying the Milky Way as the first off-world radio source, and he went on to conduct the first sky survey at very high radio frequencies, discovering other radio sources. The rapid development of radar during World War II created technology which was applied to radio astronomy after the war, and radio astronomy became a branch of astronomy, with universities and research institutes constructing large radio telescopes.
History of the telescope
Important developments in reflecting telescopes were John Hadley's production of larger paraboloidal mirrors in 1721; the process of silvering glass mirrors introduced by Léon Foucault in 1857; and the adoption of long-lasting aluminized coatings on reflector mirrors in 1932. The Ritchey-Chretien variant of Cassegrain reflector was invented around 1910, but not widely adopted until after 1950; many modern telescopes including the Hubble Space Telescope use this design, which gives a wider field of view than a classic Cassegrain.
Zacharias Janssen
The claim that Zacharias Janssen invented the telescope and the microscope dates back to the year 1655. During that time Dutch diplomat Willem Boreel conducted an investigation trying to figure out who invented the telescope. He had a local magistrate in Middelburg follow up on a 45 year old recollection of a spectacle maker named "Hans" who told a young Boreel in 1610 about inventing the telescope. In his investigation the magistrate was contacted by a then unknown claimant, Middelburg spectacle maker Johannes Zachariassen, the son of Zacharias Janssen, who testified under oath that his father invented the telescope and the microscope as early as 1590 and that Hans Lippershey had stolen his father's invention of the telescope. This testimony seemed to convincing to Boreel, who modified his recollections, concluding that Zacharias must have been who he remembered. Boreel's conclusion that Zacharias Janssen invented the telescope a little ahead of spectacle maker Hans Lippershey was adopted by Pierre Borel in his 1656 book on the subject.
Galileo Galilei
Based only on uncertain descriptions of the first practical telescope which Hans Lippershey tried to patent in the Netherlands in 1608, Galileo, in the following year, made a telescope with about 3x magnification. He later made improved versions with up to about 30x magnification. With a Galilean telescope, the observer could see magnified, upright images on the earth—it was what is commonly known as a terrestrial telescope or a spyglass. He could also use it to observe the sky; for a time he was one of those who could construct telescopes good enough for that purpose. On 25 August 1609, he demonstrated one of his early telescopes, with a magnification of about 8 or 9, to Venetian lawmakers. His telescopes were also a profitable sideline for Galileo, who sold them to merchants who found them useful both at sea and as items of trade. He published his initial telescopic astronomical observations in March 1610 in a brief treatise entitled "Sidereus Nuncius" ("Starry Messenger").
William Herschel Telescope
Construction of the telescope was by Grubb Parsons, the last telescope that company produced in its 150-year history. Work began at their workshop in Newcastle-upon-Tyne in 1983, and the telescope was shipped to La Palma in 1985 (the two other telescopes of the Isaac Newton Group began operating in 1984). The WHT saw first light on 1 June 1987; it was the third largest optical telescope in the world at the time. The total cost of the telescope, including the dome and the full initial suite of instruments, was £15M (in 1984, equivalent to £M in ); within budget once inflation is taken into account.
History of the telescope
The twentieth century saw the construction of telescopes which could produce images using wavelengths other than visible light starting in 1931 when Karl Jansky discovered astronomical objects gave off radio emissions; this prompted a new era of observational astronomy after World War II, with telescopes being developed for other parts of the electromagnetic spectrum from radio to gamma-rays.
Stereoscope
Contrary to a common assertion, David Brewster did not invent the stereoscope, as he himself was often at pains to make clear. A rival of Wheatstone, Brewster credited the invention of the device to a Mr. Elliot, a "Teacher of Mathematics" from Edinburgh, who, according to Brewster, conceived of the idea as early as 1823 and, in 1839, constructed "a simple stereoscope without lenses or mirrors", consisting of a wooden box 18 inches long, 7 inches wide and 4 inches high, which was used to view drawn landscape transparencies, since photography had yet to be invented. Brewster's personal contribution was the suggestion to use lenses for uniting the dissimilar pictures in 1849; and accordingly the lenticular stereoscope (lens based) may fairly be said to be his invention. This allowed a reduction in size, creating hand-held devices, which became known as Brewster Stereoscopes, much admired by Queen Victoria when they were demonstrated at the Great Exhibition of 1851.
Alethoscope
An alethoscope (Greek true+view) is an instrument for viewing pictures with a lens to enlarge and show them with natural relations and proportions. The alethoscope was invented by Carlo Ponti in 1860 and patented in 1861. It was used to view photographs that were colored, perforated and mounted on a curved frame. The alethoscope showed day-and-night effects whether viewing it against the light or reflect the light by two side mirrors. It is the larger version of a megalethoscope.
Optics
The first telescopes, called "refracting telescopes" were also developed with a single objective and eyepiece lens. In contrast to the microscope, the objective lens of the telescope was designed with a large focal length to avoid optical aberrations. The objective focuses an image of a distant object at its focal point which is adjusted to be at the focal point of an eyepiece of a much smaller focal length. The main goal of a telescope is not necessarily magnification, but rather collection of light which is determined by the physical size of the objective lens. Thus, telescopes are normally indicated by the diameters of their objectives rather than by the magnification which can be changed by switching eyepieces. Because the magnification of a telescope is equal to the focal length of the objective divided by the focal length of the eyepiece, smaller focal-length eyepieces cause greater magnification.
40-foot telescope
The telescope was located on the grounds of Observatory House, Herschel's house in Slough, between 1789 and 1840. The first observation with the telescope was on 19 February 1787, when Herschel pointed the then-incomplete telescope towards the Orion nebula, which he observed by crawling into the telescope and using a hand-held eyepiece: "The apparatus for the 40-foot telescope was by this time so far completed that I could put the mirror into the tube and direct it to a celestial object; but having no eye-glass fixed, not being acquainted with the focal length which was to be tried, I went into the tube, and laying down near the mouth of it I held the eye-glass in my hand, and soon found the place of the focus. The object I viewed was the nebula in the belt of Orion, and I found the figure of the mirror, though far from perfect, better than I had expected. It showed four small stars in the nebula and many more. The nebula was extremely bright."
Hale Telescope
The telescope saw first light on January 26, 1949, at 10:06pm PST under the direction of American astronomer Edwin Powell Hubble, targeting NGC 2261, an object also known as Hubble's Variable Nebula. The photographs made then were published in the astronomical literature and in the May 7, 1949 issue of "Collier's Magazine".
History of tracheal intubation
While all these surgical advances were taking place, many important developments were also taking place in the science of optics. Many new optical instruments with medical applications were invented during the 19th century. In 1805, a German army surgeon named Philipp von Bozzini (1773–1809) invented a device he called the "lichtleiter" (or light-guiding instrument). This instrument, the ancestor of the modern endoscope, was used to examine the urethra, the human urinary bladder, rectum, oropharynx and nasopharynx. The instrument consisted of a candle within a metal chimney; a mirror on the inside reflected light from the candle through attachments into the relevant body cavity. The practice of gastric endoscopy in humans was pioneered by United States Army surgeon William Beaumont (1785–1853) in 1822 with the cooperation of his patient Alexis St. Martin (1794–1880), a victim of an accidental gunshot wound to the stomach. In 1853, Antonin Jean Desormeaux (1815–1882) of Paris modified Bozzini's lichtleiter such that a mirror would reflect light from a kerosene lamp through a long metal channel. Referring to this instrument as an "endoscope" (he is credited with coining this term), Desormeaux employed it to examine the urinary bladder. However, like Bozzini's lichtleiter, Desormeaux's endoscope was of limited utility due to its propensity to become very hot during use. In 1868, Adolph Kussmaul (1822–1902) of Germany performed the first esophagogastroduodenoscopy (a diagnostic procedure in which an endoscope is used to visualize the esophagus, stomach and duodenum) on a living human. The subject was a sword-swallower, who swallowed a metal tube with a length of 47 centimeters and a diameter of 13 millimeters. On 2 October 1877, Berlin urologist Maximilian Carl-Friedrich Nitze (1848–1906) and Viennese instrument maker Josef Leiter (1830–1892) introduced the first practical cystourethroscope with an electric light source. The instrument's biggest drawback was the tungsten filament incandescent light bulb (invented by Alexander Lodygin, 1847–1923), which became very hot and required a complicated water cooling system. In 1881, Polish physician Jan Mikulicz-Radecki (1850–1905) created the first rigid gastroscope for practical applications.
Telectroscope
The term "telectroscope" was used by the French writer and publisher Louis Figuier in 1878 to popularize an invention wrongly interpreted as real and incorrectly ascribed to Alexander Graham Bell. Figuier was probably misled by the article "The Electroscope" published in "The New York Sun" of 30 March 1877. Written under the pseudonym "Electrician", the New York Sun article claimed that "an eminent scientist", whose name had to be withheld, had invented a device whereby objects or people anywhere in the world "could be seen anywhere by anybody". According to the article, the device would allow merchants to transmit pictures of their wares to their customers, the contents of museum collections would be made available to scholars in distant cities, and (combined with the telephone) operas and plays could be broadcast into people's homes.
Scientific Revolution
In 1666, Isaac Newton argued that the faults of the refracting telescope were fundamental because the lens refracted light of different colors differently. He concluded that light could not be refracted through a lens without causing chromatic aberrations. From these experiments Newton concluded that no improvement could be made in the refracting telescope. However, he was able to demonstrate that the angle of reflection remained the same for all colors, so he decided to build a reflecting telescope. It was completed in 1668 and is the earliest known functional reflecting telescope.
Visible-light astronomy
Hans Lippershey, a German-Dutch spectacle-maker, is commonly credited as being the first to invent the telescope. Lippershey is the first recorded person to apply for a patent for a telescope, however it is unclear if Lippershey was the first to build a telescope. Based only on uncertain descriptions of the telescope which Lippershey tried to obtain a patent for, Galileo made a telescope with about 3x magnification in the following year. Galileo later made improved versions with up to 30x magnification. With a Galilean telescope the observer could see magnified, upright images on the earth—it was what is commonly known as a terrestrial telescope or a spyglass. Galileo could also use it to observe the sky, and for a time was one of those who could construct telescopes good enough for that purpose. On 25 August 1609, Galileo demonstrated one of his early telescopes, with a magnification of up to 8 or 9, to Venetian lawmakers. Galileo's telescopes were also a profitable sideline; selling them to merchants who found them useful both at sea and as items of trade. He published his initial telescopic astronomical observations in March 1610 in a brief treatise entitled "Sidereus Nuncius" ("Starry Messenger").
Reflector sight
These sights are also used on astronomical telescopes as finderscopes, to help aim the telescope at the desired object. There are many commercial models, the first of which was the Telrad, invented by amateur astronomer Steve Kufeld in the late 1970s. Others are now available from companies such as Apogee, Celestron, Photon, Rigel, and Televue.
Linden Observatory Complex
Up until the 17th century, astronomy was positional and depended on observations of the naked eye. In the early 17th century a new instrument, the telescope was invented by Hans Lipperhey and quickly taken up and improved upon by Galileo Galilei. In 1610, armed with his 20 XX refractor telescope, Galileo discovered four moons of Jupiter and for the first time in the history of the world observed the movement of a satellite around a planet. Using his telescope Galileo also observed that the phases of Venus were similar to lunar phases and argued that these observations empirically supported the theory that the earth moves around the sun.
Telescopic sight
The first documented telescopic rifle sight was invented between 1835 and 1840. In a book titled "The Improved American Rifle", written in 1844, civil engineer John R. Chapman documented the first telescopic sights made by Morgan James of Utica, New York. Chapman gave James the concepts and some of the design, whereupon they produced the Chapman-James sight. In 1855, William Malcolm of Syracuse, NY began producing his own sight. Malcolm used an original design incorporating achromatic lenses like those used in telescopes, and improved the windage and elevation adjustments. They were between three and twenty magnification (possibly more). Malcolm's and those made by L. M. Amidon of Vermont were the standard during the Civil War.
Thomas Cooke (machinist)
Cooke studied optics and became interested in making telescopes, the first of which was a refracting telescope with the base of a tumbler shaped to form its lens. This led to his friends including John Phillips encouraging him to make telescopes and other optical devices commercially.
Aerial telescope
An aerial telescope is a type of very long focal length refracting telescope, built in the second half of the 17th century, that did not use a tube. Instead, the objective was mounted on a pole, tree, tower, building or other structure on a swivel ball-joint. The observer stood on the ground and held the eyepiece, which was connected to the objective by a string or connecting rod. By holding the string tight and maneuvering the eyepiece, the observer could aim the telescope at objects in the sky. The idea for this type of telescope may have originated in the late 17th century with the Dutch mathematician, astronomer and physicist Christiaan Huygens and his brother Constantijn Huygens, Jr., though it is not clear if they actually invented it.
Mount Wilson Observatory
For the 60-inch telescope, George Ellery Hale received the mirror blank, cast by Saint-Gobain in France, in 1896 as a gift from his father, William Hale. It was a glass disk 19 cm thick and weighing 860 kg. However it was not until 1904 that Hale received funding from the Carnegie Institution to build an observatory. Grinding began in 1905 and took two years. The mounting and structure for the telescope was built in San Francisco and barely survived the 1906 earthquake. Transporting the pieces to the top of Mount Wilson was an enormous task. First light was December 8, 1908. It was at the time the largest operational telescope in the world. Lord Rosse's Leviathan of Parsonstown, a 72-inch (1.8-meter) telescope built in 1845, was, by the 1890s, out of commission.
Bell 47
The "Telecopter" was a Bell Model 47 rented by television station KTLA in Los Angeles, California. It was outfitted with a television camera and it made the worlds first flight by a television news helicopter on July 3, 1958, with its inventor, John D. Silva, aboard. When the television station reported it was receiving no video, Silva exited the helicopters cockpit to climb onto its landing skid while it hovered at 1,500 feet (457 m) so he could investigate the microwave transmitter bolted to its side, where he discovered a vacuum tube had failed due to vibration and hot weather. After Silva fixed the problem overnight, the Telecopter made the world's first successful television news flight on July 4, 1958.
40-foot telescope
William Herschel's 40-foot telescope, also known as the Great Forty-Foot telescope, was a reflecting telescope constructed between 1785 and 1789 at Observatory House in Slough, England. It used a diameter primary mirror with a focal length (hence its name ""Forty-Foot""). It was the largest telescope in the world for 50 years. It may have been used to discover Enceladus and Mimas, the 6th and 7th moons of Saturn. It was dismantled in 1840; today the original mirror and a section of the tube remain.
Zacharias Janssen
Over the years there have been claims Zacharias Janssen invented the telescope and/or the microscope in Middelburg between 1590 and 1618. Zacharias worked for some period of his life as spectacle-maker (a very competitive and secretive trade) and at one time lived next door to Middelburg spectacle maker Hans Lippershey, also claimed to have invented the telescope. Janssen's attribution to these discoveries is debatable since there is no concrete evidence as to the actual inventor, and there are a whole series of confusing and conflicting claims from the testimony of his son and fellow countrymen.
History of the telescope
The 1990s saw a new generation of giant telescopes appear using active optics, beginning with the construction of the first of the two Keck telescopes in 1993. Other giant telescopes built since then include: the two Gemini telescopes, the four separate telescopes of the Very Large Telescope, and the Large Binocular Telescope.
Lens (optics)
Spectacles were invented as an improvement of the "reading stones" of the high medieval period in Northern Italy in the second half of the 13th century. This was the start of the optical industry of grinding and polishing lenses for spectacles, first in Venice and Florence in the late 13th century, and later in the spectacle-making centres in both the Netherlands and Germany.
Spectacle makers created improved types of lenses for the correction of vision based more on empirical knowledge gained from observing the effects of the lenses (probably without the knowledge of the rudimentary optical theory of the day). The practical development and experimentation with lenses led to the invention of the compound optical microscope around 1595, and the refracting telescope in 1608, both of which appeared in the spectacle-making centres in the Netherlands.
With the invention of the telescope and microscope there was a great deal of experimentation with lens shapes in the 17th and early 18th centuries by those trying to correct chromatic errors seen in lenses. Opticians tried to construct lenses of varying forms of curvature, wrongly assuming errors arose from defects in the spherical figure of their surfaces. Optical theory on refraction and experimentation was showing no single-element lens could bring all colours to a focus. This led to the invention of the compound achromatic lens by Chester Moore Hall in England in 1733, an invention also claimed by fellow Englishman John Dollond in a 1758 patent.
Most lenses are "spherical lenses": their two surfaces are parts of the surfaces of spheres. Each surface can be "convex" (bulging outwards from the lens), "concave" (depressed into the lens), or "planar" (flat). The line joining the centres of the spheres making up the lens surfaces is called the "axis" of the lens. Typically the lens axis passes through the physical centre of the lens, because of the way they are manufactured. Lenses may be cut or ground after manufacturing to give them a different shape or size. The lens axis may then not pass through the physical centre of the lens.
History of the telescope
In some of the very long refracting telescopes constructed after 1675, no tube was employed at all. The objective was mounted on a swiveling ball-joint on top of a pole, tree, or any available tall structure and aimed by means of string or connecting rod. The eyepiece was handheld or mounted on a stand at the focus, and the image was found by trial and error. These were consequently termed aerial telescopes. and have been attributed to Christiaan Huygens and his brother Constantijn Huygens, Jr. although it is not clear that they invented it. Christiaan Huygens and his brother made objectives up to diameter and focal length and others such as Adrien Auzout made telescopes with focal lengths up to . Telescopes of such great length were naturally difficult to use and must have taxed to the utmost the skill and patience of the observers. Aerial telescopes were employed by several other astronomers. Cassini discovered Saturn's third and fourth satellites in 1684 with aerial telescope objectives made by Giuseppe Campani that were in focal length.
Leonard Digges (scientist)
The writings left by Digges' colleague William Bourne contain further detail on the experiments with lenses and mirrors conducted by Leonard Digges and his son. It is these details which led some researchers, most notably Colin Ronan, to claim that Leonard Digges invented a functioning telescope sometime between 1540 and 1559. The description seemed to suggest that Digges created a rudimentary instrument incorporating lenses and a concave mirror, in a manner rather different from a modern reflecting telescope. However, the construction of lenses to the required optical precision would have been very difficult in the 16th century, and the construction of an adequate mirror would have been much harder still. It is doubtful that Digges built a successful instrument, and the optical performance required to see the details of coins lying about in fields, or private activities seven miles away was far beyond the technology of the time.
Charles Husband
Husband worked with Bernard Lovell – the founder of the Jodrell Bank Observatory near Holmes Chapel in Cheshire – on the design and construction of the observatory's first large steerable radio telescope, the "250-ft telescope" (now known as the Lovell Telescope). After attempting to adapt military radar equipment to detect cosmic rays shortly after the Second World War, Lovell had realised that a much larger aerial would be required, and constructed a 66-metre diameter dish, limited by being static, before proposing the development of an even larger steerable telescope. The idea posed such formidable engineering challenges that the project had been declared "impossible" by other engineers, but Husband is reported to have concluded at their first meeting in September 1949, "It should be easy—about the same problem as throwing a swing bridge over the Thames at Westminster."
History of the telescope
Bradley and Samuel Molyneux, having been instructed by Hadley in his methods of polishing speculum metal, succeeded in producing large reflecting telescopes of their own, one of which had a focal length of . These methods of fabricating mirrors were passed on by Molyneux to two London opticians —Scarlet and Hearn— who started a business manufacturing telescopes.
Mikhail Lomonosov
In 1762, Lomonosov presented an improved design of a reflecting telescope to the Russian Academy of Sciences forum. His telescope had its primary mirror adjusted at an angle of four degrees to the telescope's axis. This made the image focus at the side of the telescope tube, where the observer could view the image with an eyepiece without blocking the image. However, this invention was not published until 1827, so this type of telescope has become associated with a similar design by William Herschel, the Herschelian telescope.
History of the telescope
Galileo spent his time to improving the telescope, producing telescopes of increased power. His first telescope had a 3x magnification, but he soon made instruments which magnified 8x and finally, one nearly a meter long with a 37mm objective (which he would stop down to 16mm or 12mm) and a 23x magnification. With this last instrument he began a series of astronomical observations in October or November 1609, discovering the satellites of Jupiter, hills and valleys on the Moon, the phases of Venus and observed spots on the sun (using the projection method rather than direct observation). Galileo noted that the revolution of the satellites of Jupiter, the phases of Venus, rotation of the Sun and the tilted path its spots followed for part of the year pointed to the validity of the sun-centered Copernican system over other Earth-centered systems such as the one proposed by Ptolemy. Galileo's instrument was the first to be given the name "telescope". The name was invented by the Greek poet/theologian Giovanni Demisiani at a banquet held on April 14, 1611 by Prince Federico Cesi to make Galileo Galilei a member of the Accademia dei Lincei. The word was created from the Greek "tele" = 'far' and "skopein" = 'to look or see'; "teleskopos" = 'far-seeing'.
3D television
The stereoscope was first invented by Sir Charles Wheatstone in 1838. It showed that when two pictures are viewed stereoscopically, they are combined by the brain to produce 3D depth perception. The stereoscope was improved by Louis Jules Duboscq, and a famous picture of Queen Victoria was displayed at The Great Exhibition in 1851. In 1855 the Kinematoscope was invented. In the late 1890s, the British film pioneer William Friese-Greene filed a patent for a 3D movie process. On 10 June 1915, former Edison Studios chief director Edwin S. Porter and William E. Waddell presented tests in red-green anaglyph to an audience at the Astor Theater in New York City and in 1922 the first public 3D movie "The Power of Love" was displayed.
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.
Telescope
The invention of the [[achromatic lens]] in 1733 partially corrected color aberrations present in the simple lens and enabled the construction of shorter, more functional refracting telescopes. Reflecting telescopes, though not limited by the color problems seen in refractors, were hampered by the use of fast tarnishing [[speculum metal]] mirrors employed during the 18th and early 19th century—a problem alleviated by the introduction of silver coated glass mirrors in 1857, and aluminized mirrors in 1932. The maximum physical size limit for refracting telescopes is about 1 meter (40 inches), dictating that the vast majority of large optical researching telescopes built since the turn of the 20th century have been reflectors. The largest reflecting telescopes currently have objectives larger than 10 m (33 feet), and work is underway on several 30-40m designs.
The Telescope
The Telescope was a magazine for amateur astronomers published between 1931 and 1941. The magazine was first published as a quarterly under the editorship of Harlan Stetson, director of the Perkins Observatory in Ohio. It featured popular articles about contemporary research. In 1934 Stetson moved to Cambridge, Massachusetts and brought the magazine with him. Publishing duties were assumed jointly by the Harvard College Observatory and the Bond Astronomical Club, under the editorship of Donald H. Menzel. "The Telescope" became a bimonthly publication at this time.
James Lick telescope
The fabrication of the two-element achromatic objective lens, the largest lens ever made at the time, caused years of delay. The famous large telescope maker Alvan Clark was in charge of the optical design. He gave the contract for casting the high quality optical glass blanks, of a size never before attempted, to the firm of Charles Feil in Paris. One of the huge glass disks broke during shipping, and making a replacement was delayed. Finally, after 18 failed attempts, the lens was finished, transported safely across country, and on December 31, 1887, was carefully installed in the telescope tube. The builders had to wait for three days for a break in the clouds to test it. On the evening of January 3 the telescope saw first light, and users found that the instrument couldn't be focused. An error in the estimation of the lens' focal length had caused the tube to be built too long. A hacksaw was procured, the great tube was unceremoniously cut back to the proper length and the star Aldebaran came into focus.
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.
Juan Roget
A 1959 research paper by Simón de Guilleuma claimed that evidence he had uncovered pointed to the French born spectacle maker, Juan Roget, as the inventor of the telescope before Hans Lipperhey's patent application for the same device in October 1608 and that Dutch spectacle makers had copied Roget's device. Guilleuma referenced a book published in 1618, ""Telescopium: sive ars perficiendi novum illud Galilaei visorium instrumentum ad sydera in tres partes divisa"" ("Telescope, or a performance of the art and means to Galileos's new vision of the stars, in three volumes") by Italian author Hieronymi Sirturi Mediolanensis (aka Girolamo Sirtori of Milan) in which the author describes a 1609 meeting with a "withered old" spectacle maker in Girona named "Roget" who claimed to have invented the telescope. Simón de Guilleuma researched the register of deaths of Rodez Cathedral in Aveyron and found that there was a "Roget" family of spectacle makers, leading him to conclude that the spectacle maker in the Sirtori story was Juan Roget.
History of optics
The earliest known working telescopes were the refracting telescopes that appeared in the Netherlands in 1608. Their inventor is unknown: Hans Lippershey applied for the first patent that year followed by a patent application by Jacob Metius of Alkmaar two weeks later (neither was granted since examples of the device seemed to be numerous at the time). Galileo greatly improved upon these designs the following year. Isaac Newton is credited with constructing the first functional reflecting telescope in 1668, his Newtonian reflector.
Stereoscope
In 1861 Oliver Wendell Holmes created and deliberately did not patent a handheld, streamlined, much more economical viewer than had been available before. The stereoscope, which dates from the 1850s, consisted of two prismatic lenses and a wooden stand to hold the stereo card. This type of stereoscope remained in production for a century and there are still companies making them in limited production currently.
William Bourne (mathematician)
The 110th entry is what seems to be a type of telescope. The device was said to have been employed by mathematician and surveyor Leonard Digges and Bourne was asked to investigate it by Queen Elizabeth I's chief advisor Lord Burghley. Bourne's is the best description of it, and from his writing it seemed to consist of peering into a large curved mirror that reflected the image produced by a large lens (Bourne noted in his report that the device worked but had a very narrow field of view, making impractical in military applications). This "backwards" reflecting telescope predates the earliest known working telescope by 30 years but its unwieldy nature seems to have kept it from being developed.
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.
Telescope
The word "telescope" (from the Ancient Greek τῆλε, "tele" "far" and σκοπεῖν, "skopein" "to look or see"; τηλεσκόπος, "teleskopos" "far-seeing") was coined in 1611 by the Greek mathematician Giovanni Demisiani for one of Galileo Galilei's instruments presented at a banquet at the Accademia dei Lincei. In the "Starry Messenger", Galileo had used the term "perspicillum".
Stereoscope
The earliest type of stereoscope was invented by Sir Charles Wheatstone in 1838. It used a pair of mirrors at 45 degree angles to the user's eyes, each reflecting a picture located off to the side. It demonstrated the importance of binocular depth perception by showing that when two pictures simulating left-eye and right-eye views of the same object are presented so that each eye sees only the image designed for it, but apparently in the same location, the brain will fuse the two and accept them as a view of one solid three-dimensional object. Wheatstone's stereoscope was introduced in the year before the first practical photographic process became available, so drawings were used. This type of stereoscope has the advantage that the two pictures can be very large if desired.
History of the telescope
The Italian polymath Galileo Galilei was in Venice in June 1609 and there heard of the "Dutch perspective glass" by means of which distant objects appeared nearer and larger. Galileo states that he solved the problem of the construction of a telescope the first night after his return to Padua from Venice and made his first telescope the next day by fitting a convex lens in one extremity of a leaden tube and a concave lens in the other one. A few days afterwards, having succeeded in making a better telescope than the first, he took it to Venice where he communicated the details of his invention to the public and presented the instrument itself to the doge Leonardo Donato, who was sitting in full council. The senate in return settled him for life in his lectureship at Padua and doubled his salary.
Isaac Newton
From this work, he concluded that the lens of any refracting telescope would suffer from the dispersion of light into colours (chromatic aberration). As a proof of the concept, he constructed a telescope using reflective mirrors instead of lenses as the objective to bypass that problem. Building the design, the first known functional reflecting telescope, today known as a Newtonian telescope, involved solving the problem of a suitable mirror material and shaping technique. Newton ground his own mirrors out of a custom composition of highly reflective speculum metal, using Newton's rings to judge the quality of the optics for his telescopes. In late 1668, he was able to produce this first reflecting telescope. It was about eight inches long and it gave a clearer and larger image. In 1671, the Royal Society asked for a demonstration of his reflecting telescope. Their interest encouraged him to publish his notes, "Of Colours", which he later expanded into the work "Opticks". When Robert Hooke criticised some of Newton's ideas, Newton was so offended that he withdrew from public debate. Newton and Hooke had brief exchanges in 1679–80, when Hooke, appointed to manage the Royal Society's correspondence, opened up a correspondence intended to elicit contributions from Newton to Royal Society transactions, which had the effect of stimulating Newton to work out a proof that the elliptical form of planetary orbits would result from a centripetal force inversely proportional to the square of the radius vector. But the two men remained generally on poor terms until Hooke's death.
Zacharias Janssen
Zacharias Janssen (also Zacharias Jansen or Sacharias Jansen) (1585 – pre-1632) was a Dutch spectacle-maker from Middelburg associated with the invention of the first optical telescope. Janssen is sometimes also credited for inventing the first truly compound microscope. However, the origin of the microscope, just like the origin of the telescope, is a matter of debate.