1.
Aperture
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In optics, an aperture is a hole or an opening through which light travels. More specifically, the aperture and focal length of a system determine the cone angle of a bundle of rays that come to a focus in the image plane. The aperture determines how collimated the admitted rays are, which is of importance for the appearance at the image plane. If an aperture is narrow, then highly collimated rays are admitted, a wide aperture admits uncollimated rays, resulting in a sharp focus only for rays coming from a certain distance. This means that a wide aperture results in an image that is sharp for things at the correct distance, the aperture also determines how many of the incoming rays are actually admitted and thus how much light reaches the image plane. In the human eye, the pupil is the aperture, an optical system typically has many openings or structures that limit the ray bundles. In general, these structures are called stops, and the stop is the stop that primarily determines the ray cone angle. In some contexts, especially in photography and astronomy, aperture refers to the diameter of the aperture stop rather than the stop or the opening itself. For example, in a telescope, the stop is typically the edges of the objective lens or mirror. One then speaks of a telescope as having, for example, note that the aperture stop is not necessarily the smallest stop in the system. Magnification and demagnification by lenses and other elements can cause a large stop to be the aperture stop for the system. In astrophotography, the aperture may be given as a measure or as the dimensionless ratio between that measure and the focal length. In other photography, it is given as a ratio. Sometimes stops and diaphragms are called apertures, even when they are not the stop of the system. The word aperture is used in other contexts to indicate a system which blocks off light outside a certain region. In astronomy, for example, a photometric aperture around a star usually corresponds to a window around the image of a star within which the light intensity is assumed. The aperture stop is an important element in most optical designs and its most obvious feature is that it limits the amount of light that can reach the image/film plane. This can be unavoidable, as in a telescope where one wants to collect as much light as possible, or deliberate
2.
Camera obscura
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The surroundings of the projected image have to be relatively dark for the image to be clear, so many historical camera obscura experiments were performed in dark rooms. The term camera obscura also refers to constructions or devices that use of the principle within a box. Camerae obscurae with a lens in the opening have been used since the second half of the 16th century, before the term camera obscura was first used in 1604, many other expressions were used including cubiculum obscurum, cubiculum tenebricosum, conclave obscurum and locus obscurus. Rays of light travel in straight lines and change when they are reflected and partly absorbed by an object, retaining information about the color, lit objects reflect rays of light in all directions. The human eye itself works much like a camera obscura with an opening, a biconvex lens, a camera obscura device consists of a box, tent or room with a small hole in one side. Light from a scene passes through the hole and strikes a surface inside, where the scene is reproduced, inverted and reversed. The image can be projected onto paper, and can then be traced to produce an accurate representation. In order to produce a reasonably clear projected image, the aperture has to be about 1/100th the distance to the screen, many camerae obscurae use a lens rather than a pinhole because it allows a larger aperture, giving a usable brightness while maintaining focus. As the pinhole is made smaller, the image gets sharper, with too small a pinhole, however, the sharpness worsens, due to diffraction. Using mirrors, as in an 18th-century overhead version, it is possible to project a right-side-up image, another more portable type is a box with an angled mirror projecting onto tracing paper placed on the glass top, the image being upright as viewed from the back. There are theories that occurrences of camera obscura effects inspired paleolithic cave paintings and it is also suggested that camera obscura projections could have played a role in Neolithic structures. Perforated gnomons projecting an image of the sun were described in the Chinese Zhoubi Suanjing writings. The location of the circle can be measured to tell the time of day. In Arab and European cultures its invention was later attributed to Egyptian astronomer. Some ancient sightings of gods and spirits, especially in worship, are thought to possibly have been conjured up by means of camera obscura projections. In these writings it is explained how the image in a collecting-point or treasure house is inverted by an intersecting point that collected the light. Light coming from the foot of a person would partly be hidden below. Rays from the head would partly be hidden above and partly form the part of the image
3.
Virupaksha Temple, Hampi
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Virupaksha Temple is located in Hampi 350 km from Bangalore, in the state of Karnataka in southern India. It is part of the Group of Monuments at Hampi, designated a UNESCO World Heritage Site, Virupaksha is a form of Shiva and has other temples dedicated to him, notably at the Group of Monuments at Pattadakal, another World Heritage Site. The temple was built by Lakkana Dandesha, a chieftain under the ruler Deva Raya II of the Vijayanagara Empire, Hampi, capital of the Vijayanagara empire, sits on the banks of the Tungabhadra River. Virupaksha Temple is the center of pilgrimage at Hampi, and has been considered the most sacred sanctuary over the centuries. It is intact among the ruins and is still used in worship. The temple is dedicated to Lord Shiva, known here as Virupaksha, there is also a Virupakshini Amma temple in a village called Nalagamapalle, Chittoor district, Andhra Pradesh, approximately 100 km from Tirupati. The temples history is uninterrupted from about the 7th century, the Virupaksha-Pampa sanctuary existed well before the Vijayanagara capital was located here. Inscriptions referring to Shiva date back to the 9th and 10th centuries, what started as a small shrine grew into a large complex under the Vijayanagara rulers. Evidence indicates there were made to the temple in the late Chalukyan and Hoysala periods. The huge temple building was built by Lakkana Dandesha, a chieftain under the ruler Deva Raya II of the Vijayanagara Empire, under the Vijayanagara rulers, in the middle of the 14th century, there began a flowering of native art and culture. When the rulers were defeated by Muslim invaders in the 16th century, most of the wonderful decorative structures, the religious sect of Virupaksha-Pampa did not end with the destruction of the city in 1565. Worship there has persisted throughout the years, at the beginning of the 19th century there were major renovations and additions, which included ceiling paintings and the towers of the north and east gopura. At present, the temple consists of a sanctum, three ante chambers, a pillared hall and an open pillared hall. A pillared cloister, entrance gateways, courtyards, smaller shrines, the nine-tiered eastern gateway, which is the largest at 50 meters, is well-proportioned and incorporates some earlier structures. It has a superstructure and a stone base. It gives access to the court containing many sub-shrines. The smaller eastern gateway leads to the court with its numerous smaller shrines. Another gopuram towards north known as the Kanakagiri gopura, leads to an enclosure with subsidiary shrines
4.
Hampi
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Hampi is a village and temple town recognised as a UNESCO World Heritage Site, listed as the Group of Monuments at Hampi. in northern Karnataka, India. It is located within the ruins of the city of Vijayanagara, predating the city of Vijayanagara, Hampi continues to be an important religious centre, housing the Virupaksha Temple and several other monuments belonging to the old city. Hampi — traditionally known as Pampa-kshetra, Kishkindha-kshetra or Bhaskara-kshetra — is derived from Pampa, the name Hampi is an anglicized version of the Kannada name Hampe. Over the years, it has also referred to as Vijayanagara and Virupakshapura. Emperor Ashokas Rock Edicts in Nittur & Udegolan suggest that this region was part of the Maurya Empire during the 3rd century BC, a Brahmi inscription and a terracotta seal dating to the II century CE were also recovered from the excavation site. The first settlements in Hampi date from 1 CE, immediately before the rise of the Vijayanagara kings, the region was probably in the hands of chiefs of Kampili, now a small town,19 km east of Hampi. Hampi was one of the best areas of the capital of the Vijayanagara Empire from 1343 to 1565, Hampi was chosen because of its strategic location, bounded by the torrential Tungabhadra river on one side and surrounded by defensible hills on the other three sides. The ruins of Hampi were surveyed in 1800 by Scottish Colonel Colin Mackenzie, the site is significant historically and architecturally. The landscape abounds with large stones which have used to make statues of Jaina deities. The Archaeological Survey of India continues to conduct excavations in the area, the Islamic Quarter, sometimes called the Moorish Quarter, is located between the northern slope of the Malyavanta hill and the Talarigatta Gate. According to archaeologists, high-ranking Muslim officers of the kings court, Hampi is situated on the banks of the Tungabhadra River. It is 353 km from Bangalore and 74 km from Bellary, hosapete,13 km away, is the nearest railway head. The annual Hampi Utsav or Vijaya Festival has been celebrated since the reign of Vijayanagara and it is organized by the Government of Karnataka as Nada Festival. Due to the presence of mineral deposits in this region, such as iron-ore and manganese. A recent boom for the supply of iron-ore in the market has led to increased levels of mining in this district. Some feel that the World Heritage Site at Hampi and the Tungabhadra Dam are under threat as a result, the city of Vijayanagara was originally encompassed by seven lines of fortifications, which had many bastions and gateways. The seventh & the innermost fortification enclosed the city and is the best preserved. The extant monuments of Vijayanagara or Hampi can be divided into Religious, the Jain temples on Hemakuta hill, the two Devi shrines and some other structures in the Virupaksha temple complex predate the Vijayanagara Empire
5.
Ibn al-Haytham
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Abū ʿAlī al-Ḥasan ibn al-Ḥasan ibn al-Haytham, also known by the Latinization Alhazen or Alhacen, was an Arab Muslim scientist, mathematician, astronomer, and philosopher. Ibn al-Haytham made significant contributions to the principles of optics, astronomy, mathematics and he was the first to explain that vision occurs when light bounces on an object and then is directed to ones eyes. He spent most of his close to the court of the Fatimid Caliphate in Cairo and earned his living authoring various treatises. In medieval Europe, Ibn al-Haytham was honored as Ptolemaeus Secundus or simply called The Physicist and he is also sometimes called al-Baṣrī after his birthplace Basra in Iraq, or al-Miṣrī. Ibn al-Haytham was born c.965 in Basra, which was part of the Buyid emirate. Alhazen arrived in Cairo under the reign of Fatimid Caliph al-Hakim, Alhazen continued to live in Cairo, in the neighborhood of the famous University of al-Azhar, until his death in 1040. Legend has it that after deciding the scheme was impractical and fearing the caliphs anger, during this time, he wrote his influential Book of Optics and continued to write further treatises on astronomy, geometry, number theory, optics and natural philosophy. Among his students were Sorkhab, a Persian from Semnan who was his student for three years, and Abu al-Wafa Mubashir ibn Fatek, an Egyptian prince who learned mathematics from Alhazen. Alhazen made significant contributions to optics, number theory, geometry, astronomy, Alhazens work on optics is credited with contributing a new emphasis on experiment. In al-Andalus, it was used by the prince of the Banu Hud dynasty of Zaragossa and author of an important mathematical text. A Latin translation of the Kitab al-Manazir was made probably in the twelfth or early thirteenth century. His research in catoptrics centred on spherical and parabolic mirrors and spherical aberration and he made the observation that the ratio between the angle of incidence and refraction does not remain constant, and investigated the magnifying power of a lens. His work on catoptrics also contains the known as Alhazens problem. Alhazen wrote as many as 200 books, although only 55 have survived, some of his treatises on optics survived only through Latin translation. During the Middle Ages his books on cosmology were translated into Latin, Hebrew, the crater Alhazen on the Moon is named in his honour, as was the asteroid 59239 Alhazen. In honour of Alhazen, the Aga Khan University named its Ophthalmology endowed chair as The Ibn-e-Haitham Associate Professor, Alhazen, by the name Ibn al-Haytham, is featured on the obverse of the Iraqi 10, 000-dinar banknote issued in 2003, and on 10-dinar notes from 1982. The 2015 International Year of Light celebrated the 1000th anniversary of the works on optics by Ibn Al-Haytham, Alhazens most famous work is his seven-volume treatise on optics Kitab al-Manazir, written from 1011 to 1021. Optics was translated into Latin by a scholar at the end of the 12th century or the beginning of the 13th century
6.
Solar eclipse
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As seen from the Earth, a solar eclipse is a type of eclipse that occurs when the Moon passes between the Sun and Earth, and the Moon fully or partially blocks the Sun. This can happen only at new moon when the Sun and the Moon are in conjunction as seen from Earth in an alignment referred to as syzygy, in a total eclipse, the disk of the Sun is fully obscured by the Moon. In partial and annular eclipses, only part of the Sun is obscured, if the Moon were in a perfectly circular orbit, a little closer to the Earth, and in the same orbital plane, there would be total solar eclipses every month. However, the Moons orbit is inclined at more than 5 degrees to the Earths orbit around the Sun, Earths orbit is called the ecliptic plane as the Moons orbit must cross this plane in order for an eclipse to occur. In addition, the Moons actual orbit is elliptical, often taking it far away from Earth that its apparent size is not large enough to block the Sun totally. The orbital planes cross each other at a line of nodes resulting in at least two, and up to five, solar eclipses occurring each year, no more than two of which can be total eclipses. However, total solar eclipses are rare at any particular location because totality exists only along a path on the Earths surface traced by the Moons shadow or umbra. An eclipse is a natural phenomenon, nevertheless, in some ancient and modern cultures, solar eclipses have been attributed to supernatural causes or regarded as bad omens. A total solar eclipse can be frightening to people who are unaware of its explanation, as the Sun seems to disappear during the day. People referred to as eclipse chasers or umbraphiles will travel to locations to observe or witness predicted central solar eclipses. For the date of the next eclipse see the section Recent, during any one eclipse, totality occurs at best only in a narrow track on the surface of Earth. An annular eclipse occurs when the Sun and Moon are exactly in line with the Earth, hence the Sun appears as a very bright ring, or annulus, surrounding the dark disk of the Moon. A hybrid eclipse shifts between a total and annular eclipse, at certain points on the surface of Earth, it appears as a total eclipse, whereas at other points it appears as annular. A partial eclipse occurs when the Sun and Moon are not exactly in line with the Earth and this phenomenon can usually be seen from a large part of the Earth outside of the track of an annular or total eclipse. However, some eclipses can only be seen as an eclipse, because the umbra passes above the Earths polar regions. Partial eclipses are virtually unnoticeable in terms of the suns brightness, even at 99%, it would be no darker than civil twilight. Of course, partial eclipses can be observed if one is viewing the sun through a darkening filter, the Suns distance from Earth is about 400 times the Moons distance, and the Suns diameter is about 400 times the Moons diameter. Because these ratios are approximately the same, the Sun and the Moon as seen from Earth appear to be approximately the same size, about 0.5 degree of arc in angular measure
7.
Giambattista della Porta
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Giambattista della Porta, also known as Giovanni Battista Della Porta was an Italian scholar, polymath and playwright who lived in Naples at the time of the Scientific Revolution and Reformation. Giambattista della Porta spent the majority of his life on scientific endeavors and he benefited from an informal education of tutors and visits from renowned scholars. His most famous work, first published in 1558, was entitled Magiae Naturalis, in this book he covered a variety of the subjects he had investigated, including the study of, occult philosophy, astrology, alchemy, mathematics, meteorology, and natural philosophy. He was also referred to as professor of secrets, Giambattista della Porta was born at Vico Equense, near Naples, to the nobleman Nardo Antonio della Porta. He was the third of four sons, second to survive childhood, having an older brother Gian Vincenzo, Della Porta had a privileged childhood including his education. His father had a thirst for learning, a trait he would pass all of his children. He surrounded himself with distinguished people and entertained the likes of philosophers, mathematicians, poets, the atmosphere of the house resembled an academy for his sons. The members of the circle of friends stimulated the boys, tutoring and mentoring them. It is possible that his fathers interest and influence in providing a well-rounded education helped to turn della Porta into the Renaissance man that he was to become. As well as having talents for the sciences and mathematics, all the brothers were also interested in the arts. Despite their interest none of them possessed any sort of talent for it and they were all accepted into the Scuola di Pitagora, a highly exclusive academy of musicians. Apparently the pure impressiveness of their intellect was enough to allow three tone-deaf mathematicians into a school for the musically gifted, the status of the family as a symbol of knowledge and intellectual growth surely helped in their acceptance as well. More aware of their social position than the idea that his sons could have professions in science, Nardo Antonio was raising the more as gentlemen. Therefore, the boys struggled with singing, as that was considered an accomplishment of gentlemen. They were taught to dance, ride, to part and perform well in tournaments and games. The training gave della Porta, at least earlier in his life, a taste for the aspects of his privileged living. This kind of lifestyle, the façade and showmanship involved in presenting ones self carried with Giambattista throughout his life, in 1563, della Porta published De Furtivis Literarum Notis, a work about cryptography. In it he described the first known digraphic substitution cipher, charles J. Mendelsohn commented, He was, in my opinion, the outstanding cryptographer of the Renaissance
8.
David Brewster
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Sir David Brewster KH PRSE FRS FSA FSSA MICE was a Scottish physicist, mathematician, astronomer, inventor, writer, historian of science and university principal. Most noted for his contributions to the field of optics, he studied the double refraction by compression and discovered the photoelastic effect, for his work, William Whewell dubbed him the Father of modern experimental optics and the Johannes Kepler of Optics. He is well-recognized for being the inventor of the kaleidoscope and a version of the stereoscope applied to photography. He called it the lenticular stereoscope, which was the first portable and he also invented the binocular camera, two types of polarimeters, the polyzonal lens and the lighthouse illuminator. A prominent figure in the popularization of science, he is considered one of the founders of the British Association, in addition, he became the public face of higher education in Scotland, acting as Principal of the University of St Andrews and then Edinburgh between 1837 and 1868. Brewster also edited the 18-volume Edinburgh Encyclopædia, David Brewster was born at the Canongate in Jedburgh, Roxburghshire, to Margaret Key and James Brewster, the rector of Jedburgh Grammar School and a teacher of high reputation. David was the third of six children, two daughters and four sons, James, minister at Craig, Ferryden, David, George, minister at Scoonie, Fife, and Patrick, minister at the abbey church, Paisley. At the age of 12, David was sent to the University of Edinburgh and he was licensed a minister of the Church of Scotland, but only preached from the pulpit on one occasion. Though Brewster duly finished his studies and was licensed to preach. In 1799 fellow-student Henry Brougham persuaded him to study the diffraction of light, the results of his investigations were communicated from time to time in papers to the Philosophical Transactions of London and other scientific journals. A lesser-known classmate of his, Thomas Dick, also went on to become a popular astronomical writer, as early as 1807 the degree of LL. D. In 1821, he was made a member of the Royal Swedish Academy of Sciences. As a reflection of this fame, Brewster portrait was printed in some cigar boxes. Brewster chose renowned achromatic lens developer Philip Carpenter as the manufacturer of the kaleidoscope in 1817. Although Brewster patented the kaleidoscope in 1817, a copy of the prototype was shown to London opticians, as a consequence, the kaleidoscope became produced in large numbers, but yielded no direct financial benefits to Brewster. It proved to be a success with two hundred thousand kaleidoscopes sold in London and Paris in just three months. A much more valuable and practical result of Brewsters optical researches was the improvement of the British lighthouse system, although Brewsters own discoveries were important, they were not his only service to science. He began writing in 1799 as a contributor to the Edinburgh Magazine
9.
Thomas Edison
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Thomas Alva Edison was an American inventor and businessman, who has been described as Americas greatest inventor. He developed many devices that greatly influenced life around the world, including the phonograph, the motion picture camera, and the long-lasting, practical electric light bulb. Edison was an inventor, holding 1,093 US patents in his name, as well as many patents in the United Kingdom, France. Edisons inventions contributed to mass communication and, in particular, telecommunications and these included a stock ticker, a mechanical vote recorder, a battery for an electric car, electrical power, recorded music and motion pictures. His advanced work in these fields was an outgrowth of his career as a telegraph operator. Edison developed a system of generation and distribution to homes, businesses. His first power station was on Pearl Street in Manhattan, New York, Thomas Edison was born in Milan, Ohio, and grew up in Port Huron, Michigan. He was the seventh and last child of Samuel Ogden Edison, Jr. and Nancy Matthews Elliott. His father, the son of a Loyalist refugee, had moved as a boy with the family from Nova Scotia, settling in southwestern Ontario, in a known as Shewsbury, later Vienna. Samuel Jr. eventually fled Ontario because he took part in the unsuccessful Mackenzie Rebellion of 1837 and his father, Samuel Sr. had earlier fought in the War of 1812 as captain of the First Middlesex Regiment. By contrast, Samuel Jr. s struggle found him on the losing side, once across the border, he found his way to Milan, Ohio. His patrilineal family line was Dutch by way of New Jersey and his mother taught him at home. Much of his education came from reading R. G, parkers School of Natural Philosophy and The Cooper Union for the Advancement of Science and Art. Edison developed hearing problems at an early age, the cause of his deafness has been attributed to a bout of scarlet fever during childhood and recurring untreated middle-ear infections. In his later years, he modified the story to say the injury occurred when the conductor, in helping him onto a moving train, Edisons family moved to Port Huron, Michigan, after the railroad bypassed Milan in 1854 and business declined. Edison sold candy and newspapers on trains running from Port Huron to Detroit and he briefly worked as a telegraph operator in 1863 for the Grand Trunk Railway at Stratford, Ontario railway at age 16. He was held responsible for a near collision and he also studied qualitative analysis and conducted chemical experiments on the train until he left the job. Edison obtained the right to sell newspapers on the road, and, with the aid of four assistants, he set in type and printed the Grand Trunk Herald
10.
Kinetoscope
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The Kinetoscope is an early motion picture exhibition device. The Kinetoscope was designed for films to be viewed by one individual at a time through a peephole viewer window at the top of the device, a prototype for the Kinetoscope was shown to a convention of the National Federation of Womens Clubs on May 20,1891. The first public demonstration of the Kinetoscope was held at the Brooklyn Institute of Arts, in 1895, Edison introduced the Kinetophone, which joined the Kinetoscope with a cylinder phonograph. Film projection, which Edison initially disdained as financially nonviable, soon superseded the Kinetoscopes individual exhibition model, many of the projection systems developed by Edisons firm in later years would use the Kinetoscope name. An encounter with the work and ideas of photographic pioneer Eadweard Muybridge appears to have spurred Edison to pursue the development of a motion picture system. The Edison facility was very close by, and the lecture was attended by both Edison and his companys official photographer, William Dickson. No such collaboration was undertaken, but in October 1888, Edison filed a claim, known as a caveat. Patent Office announcing his plans to create a device that would do for the Eye what the phonograph does for the Ear. It is clear that it was intended as part of a complete audiovisual system, in March 1889, a second caveat was filed, in which the proposed motion picture device was given a name, Kinetoscope, derived from the Greek roots kineto- and scopos. Edison assigned Dickson, one of his most talented employees, to the job of making the Kinetoscope a reality, the Edison laboratory, though, worked as a collaborative organization. Laboratory assistants were assigned to work on many projects while Edison supervised and involved himself, Dickson and his then lead assistant, Charles Brown, made halting progress at first. An audio cylinder would provide synchronized sound, while the rotating images, when tests were made with images expanded to a mere 1/8 of an inch in width, the coarseness of the silver bromide emulsion used on the cylinder became unacceptably apparent. The first film made for the Kinetoscope, and apparently the first motion picture ever produced on film in the United States, may have been shot at this time, known as Monkeyshines. 1, it shows an employee of the lab in an apparently tongue-in-cheek display of physical dexterity, attempts at synchronizing sound were soon left behind, while Dickson would also experiment with disc-based exhibition designs. The project would soon head off in more directions, largely impelled by a trip of Edisons to Europe. The first motion system to employ a perforated image band was apparently the Théâtre Optique. Reynauds system did not use film, but images painted on gelatine frames. At the Exposition Universelle, Edison would have both the Théâtre Optique and the electrical tachyscope of German inventor Ottamar Anschütz
11.
Long-exposure photography
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Long-exposure photography captures one element that conventional photography does not, time. The paths of bright moving objects become clearly visible, clouds form broad bands, head and tail lights of cars become bright streaks, stars form trails in the sky and water smooths over. Only bright objects will form visible trails, however, dark objects usually disappear, boats during daytime long exposures will disappear, but will form bright trails from their lights at night. Whereas there is no fixed definition of what constitutes long, the intent is to create a photo that shows the effect of passing time. A 30-minute photo of an object and surrounding cannot be distinguished from a short exposure, hence. Images with exposure times of several minutes also tend to make moving people or dark objects disappear, often adding a serene, when a scene includes both stationary and moving subjects, a slow shutter speed can cause interesting effects, such as light trails. Long exposures are easiest to accomplish in low-light conditions, but can be done in brighter light using neutral density filters or specially designed cameras, when using a dense neutral density filter your cameras auto focus will not be able to function. It is best to compose and focus without the filter, then once you are happy with the composition, switch to manual focus and put the neutral density filter back on. Long-exposure photography is used in a night-time setting, where the lack of light forces longer exposures. Increasing ISO sensitivity allows for shorter exposures, but substantially decreases image quality through reduced dynamic range and higher noise. By leaving the cameras shutter open for a period of time, more light is absorbed. If the camera is stationary for the period of time that the shutter is open. In this technique, a scene is very dark and the photographer or an assistant takes a light source—it can be small penlight—and moves it about in patterns. The light source can be turned off between strokes, often, stationary objects in the scene are illuminated by briefly turning on studio lights, by one or more flashes from a strobe light, or by increasing the aperture. Long exposures can blur moving water so it has mist-like qualities while keeping stationary objects like land, solargraphy is a technique in which a fixed pinhole camera is used to expose photographic paper for an extremely long amount of time. It is most often used to show the path of the Sun across the sky, one example of this is a single six-month exposure taken by photographer Justin Quinnell, showing sun-trails over Clifton Suspension Bridge between 19 December 2007 and 21 June 2008. Part of the Slow light,6 months over Bristol exhibition and this method of solargraphy uses a simple pinhole camera securely fixed in a position which wont be disturbed. Quinnel constructed his camera from an empty drink can with a 0. 25mm aperture, on February 3,2015 a pinhole camera used in a Georgia State University solargraphy art project was blown up by the Atlanta bomb squad
12.
Charge-coupled device
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A charge-coupled device is a device for the movement of electrical charge, usually from within the device to an area where the charge can be manipulated, for example conversion into a digital value. This is achieved by shifting the signals between stages within the one at a time. CCDs move charge between capacitive bins in the device, with the shift allowing for the transfer of charge between bins, in recent years CCD has become a major technology for digital imaging. In a CCD image sensor, pixels are represented by p-doped metal-oxide-semiconductors capacitors, the charge-coupled device was invented in 1969 at AT&T Bell Labs by Willard Boyle and George E. Smith. The lab was working on bubble memory when Boyle and Smith conceived of the design of what they termed, in their notebook. The device could be used as a shift register, the essence of the design was the ability to transfer charge along the surface of a semiconductor from one storage capacitor to the next. The concept was similar in principle to the device, which was developed at Philips Research Labs during the late 1960s. The first patent on the application of CCDs to imaging was assigned to Michael Tompsett, the initial paper describing the concept listed possible uses as a memory, a delay line, and an imaging device. The first experimental device demonstrating the principle was a row of closely spaced metal squares on a silicon surface electrically accessed by wire bonds. The first working CCD made with integrated circuit technology was a simple 8-bit shift register and this device had input and output circuits and was used to demonstrate its use as a shift register and as a crude eight pixel linear imaging device. Development of the device progressed at a rapid rate, by 1971, Bell researchers led by Michael Tompsett were able to capture images with simple linear devices. Several companies, including Fairchild Semiconductor, RCA and Texas Instruments, picked up on the invention, fairchilds effort, led by ex-Bell researcher Gil Amelio, was the first with commercial devices, and by 1974 had a linear 500-element device and a 2-D100 x 100 pixel device. Steven Sasson, an engineer working for Kodak, invented the first digital still camera using a Fairchild 100 x 100 CCD in 1975. The first KH-11 KENNAN reconnaissance satellite equipped with charge-coupled device array technology for imaging was launched in December 1976, under the leadership of Kazuo Iwama, Sony also started a large development effort on CCDs involving a significant investment. Eventually, Sony managed to mass-produce CCDs for their camcorders, before this happened, Iwama died in August 1982, subsequently, a CCD chip was placed on his tombstone to acknowledge his contribution. He was also awarded the 2012 IEEE Edison Medal For pioneering contributions to imaging devices including CCD Imagers, cameras, in a CCD for capturing images, there is a photoactive region, and a transmission region made out of a shift register. An image is projected through a lens onto the capacitor array, once the array has been exposed to the image, a control circuit causes each capacitor to transfer its contents to its neighbor. The last capacitor in the array dumps its charge into a charge amplifier, by repeating this process, the controlling circuit converts the entire contents of the array in the semiconductor to a sequence of voltages
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