1.
Heidelberg
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Heidelberg is a college town situated on the river Neckar in south-west Germany. At the 2015 census, its population was 156,257, located about 78 km south of Frankfurt, Heidelberg is the fifth-largest city in the German state of Baden-Württemberg. Heidelberg is part of the densely populated Rhine-Neckar Metropolitan Region, founded in 1386, Heidelberg University is Germanys oldest and one of Europes most reputable universities. A scientific hub in Germany, the city of Heidelberg is home to internationally renowned research facilities adjacent to its university. Heidelberg is in the Rhine Rift Valley, on the bank of the lower part of the Neckar in a steep valley in the Odenwald. It is bordered by the Königsstuhl and the Gaisberg mountains, the Neckar here flows in an east-west direction. On the right bank of the river, the Heiligenberg mountain rises to a height of 445 meters, the Neckar flows into the Rhine approximately 22 kilometres north-west in Mannheim. Villages incorporated during the 20th century stretch from the Neckar Valley along the Bergstraße, Heidelberg is on European walking route E1. Alongside the Philosophenweg on the side of the Old Town. There is a population of African rose-ringed parakeets, and a wild population of Siberian swan geese. Heidelberg is an authority within the Regierungsbezirk Karlsruhe. The Rhein-Neckar-Kreis rural district surrounds it and has its seat in the town, Heidelberg is a part of the Rhine-Neckar Metropolitan Region, often referred to as the Rhein-Neckar Triangle. The Rhein-Neckar Triangle became a European metropolitan area in 2005, Heidelberg consists of 15 districts distributed in six sectors of the town. The new district will have approximately 5, 000–6,000 residents, Heidelberg has an oceanic climate, defined by the protected valley between the Pfälzerwald and the Odenwald. Year-round, the temperatures are determined by maritime air masses coming from the west. In contrast to the nearby Upper Rhine Plain, Heidelbergs position in the leads to more frequent easterly winds than average. The hillsides of the Odenwald favour clouding and precipitation, the warmest month is July, the coldest is January. Temperatures often rise beyond 30 °C in midsummer, according to the German Meteorological Service, Heidelberg was the warmest place in Germany in 2009
2.
German Confederation
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Most historians have judged the Confederation to have been weak and ineffective, as well as an obstacle to the creation of a German nation-state. It collapsed due to the rivalry between Prussia and Austria, warfare, the 1848 revolution, and the inability of the members to compromise. In 1848, revolutions by liberals and nationalists were an attempt to establish a unified German state. Talks between the German states failed in 1848, and the Confederation briefly dissolved, but was re-established shortly after and it decidedly fell apart only after the Prussian victory in the Seven Weeks War of 1866. This led to the creation of the North German Confederation under Prussian leadership in 1867, a number of South German states remained independent until they joined the North German Confederation, which was renamed the German Empire. The War of the Third Coalition lasted from about 1803 to 1806, following defeat at the Battle of Austerlitz by the French under Napoleon in December 1805, Holy Roman Emperor Francis II abdicated, and the Empire was dissolved on 6 August 1806. The resulting Treaty of Pressburg established the Confederation of the Rhine in July 1806, after the Battle of Jena–Auerstedt of October 1806 in the War of the Fourth Coalition, various other German states, including Saxony and Westphalia, also joined the Confederation. Only Austria, Prussia, Danish Holstein, Swedish Pomerania and the French-occupied Principality of Erfurt stayed outside the Confederation of the Rhine and these nations would later join in the War of the Sixth Coalition from 1812 to 1814. The German Confederation was created by the 9th Act of the Congress of Vienna on 8 June 1815 after being alluded to in Article 6 of the 1814 Treaty of Paris, ending the War of the Sixth Coalition. The Confederation was formally created by a treaty, the Final Act of the Ministerial Conference to Complete and Consolidate the Organization of the German Confederation. This treaty was not concluded and signed by the parties until 15 May 1820, States joined the German Confederation by becoming parties to the second treaty. The German Confederation ended as a result of the Austro-Prussian War of 1866 between Austrian Empire and its allies on one side and the Kingdom of Prussia and its allies on the other. In the Prague peace treaty, on 23 August 1866, Austria had to accept that the Confederation was considered to be dissolved, the following day, the remaining member states confirmed the dissolution. The treaty allowed Prussia to create a new Bundesverhältnis in the North of Germany, the South German states were proposed to create a South German Confederation but this did not come into existence. Prussia and its allies created the North German Confederation in 1867, because of French intervention it had to exclude, besides Austria, the South German states Bavaria, Württemberg, Baden and Hesse-Darmstadt. During November 1870 the four states joined the North German Confederation by treaty. The North German Confederation Reichstag and Bundesrat accepted to rename the North German Confederation as the German Empire, the new constitution of the state, the Constitution of the German Confederation, introduced the new name and title on 1 January 1871. The Austrian Empire and the Kingdom of Prussia were the largest, Austria and Prussia each had one vote in the Federal Assembly
3.
Weimar Republic
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Weimar Republic is an unofficial, historical designation for the German state between 1919 and 1933. The name derives from the city of Weimar, where its constitutional assembly first took place, the official name of the state was still Deutsches Reich, it had remained unchanged since 1871. In English the country was known simply as Germany. A national assembly was convened in Weimar, where a new constitution for the Deutsches Reich was written, in its fourteen years, the Weimar Republic faced numerous problems, including hyperinflation, political extremism, and contentious relationships with the victors of the First World War. The people of Germany blamed the Weimar Republic rather than their leaders for the countrys defeat. However, the Weimar Republic government successfully reformed the currency, unified tax policies, Weimar Germany eliminated most of the requirements of the Treaty of Versailles, it never completely met its disarmament requirements, and eventually paid only a small portion of the war reparations. Under the Locarno Treaties, Germany accepted the borders of the republic. From 1930 onwards President Hindenburg used emergency powers to back Chancellors Heinrich Brüning, Franz von Papen, the Great Depression, exacerbated by Brünings policy of deflation, led to a surge in unemployment. In 1933, Hindenburg appointed Adolf Hitler as Chancellor with the Nazi Party being part of a coalition government, the Nazis held two out of the remaining ten cabinet seats. Von Papen as Vice Chancellor was intended to be the éminence grise who would keep Hitler under control, within months the Reichstag Fire Decree and the Enabling Act of 1933 had brought about a state of emergency, it wiped out constitutional governance and civil liberties. Hitlers seizure of power was permissive of government by decree without legislative participation and these events brought the republic to an end, as democracy collapsed, a single-party state founded the Nazi era. The Weimar Republic is so called because the assembly that adopted its constitution met at Weimar, Germany from 6 February 1919 to 11 August 1919, but this name only became mainstream after 1933. To the right of the spectrum the politically engaged rejected the new democratic model, the Catholic Centre party, Zentrum favoured the term Deutscher Volksstaat while on the moderate left the Chancellors SPD preferred Deutsche Republik. Only during the 1930s did the term become mainstream, both within and outside Germany, after the introduction of the republic, the flag and coat of arms of Germany were officially altered to reflect the political changes. The Weimar Republic retained the Reichsadler, but without the symbols of the former Monarchy and this left the black eagle with one head, facing to the right, with open wings but closed feathers, with a red beak, tongue and claws and white highlighting. If the Reichs Eagle is shown without a frame, the charge and colors as those of the eagle of the Reichs coat of arms are to be used. The patterns kept by the Federal Ministry of the Interior are decisive for the heraldic design, the artistic design may be varied for each special purpose. The achievements and signs of movement were mostly done away with after its downfall
4.
Astrophotography
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Astrophotography is a specialized type of photography for recording photos of astronomical objects and large areas of the night sky. The first photograph of an object was taken in 1840. This is done by long time exposure since both film and digital cameras can accumulate and sum light photons over long periods of time. Astrophotography is a subdiscipline in amateur astronomy usually seeking aesthetically pleasing images rather than scientific data. Amateurs use a range of special equipment and techniques. With a few exceptions, astronomical photography employs long exposures since both film and digital imaging devices can accumulate and light photons over long periods of time, the amount of light hitting the film or detector is also increased by increasing the diameter of the primary optics being used. Since the Earth is constantly rotating, telescopes and equipment are rotated in the direction to follow the apparent motion of the stars overhead. This is accomplished by using either equatorial or computer-controlled altazimuth telescope mounts to keep celestial objects centered while the earth rotates, all telescope mount systems suffer from induced tracking error due to imperfect motor drives and mechanical sag of the telescope. Tracking errors are corrected by keeping a selected aiming point, usually a bright guide star, sometimes the object to be imaged is moving, so the telescope has to be kept constantly centered on that object. Guiding was formerly done manually throughout the exposure with an observer standing at the telescope making corrections to keep a cross hair on the guide star, since the advent of computer-controlled systems this is accomplished by an automated systems in professional and even amateur equipment. These all require specialized equipment such as telescopes designed for imaging, for wide field of view. Astronomical CCD cameras may use cryogenic cooling to reduce thermal noise, specialized filters are also used to record images in specific wavelengths. The development of astrophotography as a tool was pioneered in the mid-19th century for the most part by experimenters and amateur astronomers. Because of the long exposures needed to capture relatively faint astronomical objects. Early photographic processes also had limitations, the daguerreotype process was far too slow to record anything but the brightest objects, and the wet plate collodion process limited exposures to the time the plate could stay wet. The first-known attempt at astronomical photography was by Louis Jacques Mandé Daguerre, inventor of the process which bears his name. Tracking errors in guiding the telescope during the long exposure meant the photograph came out as an indistinct fuzzy spot, the Sun may have been first photographed in an 1845 daguerreotype by the French physicists Léon Foucault and Hippolyte Fizeau. No photographic alteration was caused by the light of the corona condensed by a lens for two minutes, during totality, on a sheet of paper prepared with bromide of silver, the Suns solar corona was first successfully imaged during the Solar eclipse of July 28,1851
5.
Astronomy
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Astronomy is a natural science that studies celestial objects and phenomena. It applies mathematics, physics, and chemistry, in an effort to explain the origin of those objects and phenomena and their evolution. Objects of interest include planets, moons, stars, galaxies, and comets, while the phenomena include supernovae explosions, gamma ray bursts, more generally, all astronomical phenomena that originate outside Earths atmosphere are within the purview of astronomy. A related but distinct subject, physical cosmology, is concerned with the study of the Universe as a whole, Astronomy is the oldest of the natural sciences. The early civilizations in recorded history, such as the Babylonians, Greeks, Indians, Egyptians, Nubians, Iranians, Chinese, during the 20th century, the field of professional astronomy split into observational and theoretical branches. Observational astronomy is focused on acquiring data from observations of astronomical objects, theoretical astronomy is oriented toward the development of computer or analytical models to describe astronomical objects and phenomena. The two fields complement each other, with theoretical astronomy seeking to explain the results and observations being used to confirm theoretical results. Astronomy is one of the few sciences where amateurs can play an active role, especially in the discovery. Amateur astronomers have made and contributed to many important astronomical discoveries, Astronomy means law of the stars. Astronomy should not be confused with astrology, the system which claims that human affairs are correlated with the positions of celestial objects. Although the two share a common origin, they are now entirely distinct. Generally, either the term astronomy or astrophysics may be used to refer to this subject, however, since most modern astronomical research deals with subjects related to physics, modern astronomy could actually be called astrophysics. Few fields, such as astrometry, are purely astronomy rather than also astrophysics, some titles of the leading scientific journals in this field includeThe Astronomical Journal, The Astrophysical Journal and Astronomy and Astrophysics. In early times, astronomy only comprised the observation and predictions of the motions of objects visible to the naked eye, in some locations, early cultures assembled massive artifacts that possibly had some astronomical purpose. Before tools such as the telescope were invented, early study of the stars was conducted using the naked eye, most of early astronomy actually consisted of mapping the positions of the stars and planets, a science now referred to as astrometry. From these observations, early ideas about the motions of the planets were formed, and the nature of the Sun, Moon, the Earth was believed to be the center of the Universe with the Sun, the Moon and the stars rotating around it. This is known as the model of the Universe, or the Ptolemaic system. The Babylonians discovered that lunar eclipses recurred in a cycle known as a saros
6.
Heidelberg University
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Heidelberg University is a public research university in Heidelberg, Baden-Württemberg, Germany. Founded in 1386 on instruction of Pope Urban VI, Heidelberg is Germanys oldest university and it was the third university established in the Holy Roman Empire. Heidelberg has been an institution since 1899. The university consists of twelve faculties and offers programmes at undergraduate, graduate. The language of instruction is usually German, while a number of graduate degrees are offered in English. Associated with 31 Nobel Prize laureates, the university places an emphasis on research, modern scientific psychiatry, psychopharmacology, psychiatric genetics, environmental physics, and modern sociology were introduced as scientific disciplines by Heidelberg faculty. Approximately 1,000 doctorates are completed every year, with more than one third of the students coming from abroad. International students from some 130 countries account for more than 20 percent of the student body. The universitys noted alumni include eleven domestic and foreign Heads of State or Heads of Government, the Great Schism of 1378 made it possible for Heidelberg, a relatively small city and capital of the Electorate of the Palatinate, to gain its own university. The Great Schism was initiated by the election of two popes after the death of Pope Gregory XI in the same year, one successor resided in Avignon and the other in Rome. Rupert I recognized the opportunity and initiated talks with the Curia, as specified in the papal charter, the university was modelled after University of Paris and included four faculties, philosophy, theology, jurisprudence, and medicine. On 18 October 1386 a special Pontifical High Mass in the Heiliggeistkirche was the ceremony that established the university, on 19 October 1386 the first lecture was held, making Heidelberg the oldest university in Germany. In November 1386, Marsilius of Inghen was elected first rector of the university, the rector seal motto was semper apertus—i. e. The book of learning is always open, the university grew quickly and in March 1390,185 students were enrolled at the university. This resulted in establishing a reputation for the university and its professors. Due to the influence of Marsilius, the university initially taught the nominalism or via moderna, the transition from scholastic to humanistic culture was effected by the chancellor and bishop Johann von Dalberg in the late 15th century. Humanism was represented at Heidelberg University particularly by the founder of the older German Humanistic School Rudolph Agricola, Conrad Celtes, Jakob Wimpfeling, and Johann Reuchlin. Æneas Silvius Piccolomini was chancellor of the university in his capacity of provost of Worms, in 1482, Pope Sixtus IV permitted laymen and married men to be appointed professors in the ordinary of medicine through a papal dispensation
7.
Minor planet
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A minor planet is an astronomical object in direct orbit around the Sun that is neither a planet nor exclusively classified as a comet. Minor planets can be dwarf planets, asteroids, trojans, centaurs, Kuiper belt objects, as of 2016, the orbits of 709,706 minor planets were archived at the Minor Planet Center,469,275 of which had received permanent numbers. The first minor planet to be discovered was Ceres in 1801, the term minor planet has been used since the 19th century to describe these objects. The term planetoid has also used, especially for larger objects such as those the International Astronomical Union has called dwarf planets since 2006. Historically, the asteroid, minor planet, and planetoid have been more or less synonymous. This terminology has become complicated by the discovery of numerous minor planets beyond the orbit of Jupiter. A Minor planet seen releasing gas may be classified as a comet. Before 2006, the IAU had officially used the term minor planet, during its 2006 meeting, the IAU reclassified minor planets and comets into dwarf planets and small Solar System bodies. Objects are called dwarf planets if their self-gravity is sufficient to achieve hydrostatic equilibrium, all other minor planets and comets are called small Solar System bodies. The IAU stated that the minor planet may still be used. However, for purposes of numbering and naming, the distinction between minor planet and comet is still used. Hundreds of thousands of planets have been discovered within the Solar System. The Minor Planet Center has documented over 167 million observations and 729,626 minor planets, of these,20,570 have official names. As of March 2017, the lowest-numbered unnamed minor planet is 1974 FV1, as of March 2017, the highest-numbered named minor planet is 458063 Gustavomuler. There are various broad minor-planet populations, Asteroids, traditionally, most have been bodies in the inner Solar System. Near-Earth asteroids, those whose orbits take them inside the orbit of Mars. Further subclassification of these, based on distance, is used, Apohele asteroids orbit inside of Earths perihelion distance. Aten asteroids, those that have semi-major axes of less than Earths, Apollo asteroids are those asteroids with a semimajor axis greater than Earths, while having a perihelion distance of 1.017 AU or less. Like Aten asteroids, Apollo asteroids are Earth-crossers, amor asteroids are those near-Earth asteroids that approach the orbit of Earth from beyond, but do not cross it
8.
Astronomer
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An astronomer is a scientist in the field of astronomy who concentrates their studies on a specific question or field outside of the scope of Earth. They look at stars, planets, moons, comets and galaxies, as well as other celestial objects — either in observational astronomy. Examples of topics or fields astronomers work on include, planetary science, solar astronomy, there are also related but distinct subjects like physical cosmology which studies the Universe as a whole. Astronomers usually fit into two types, Observational astronomers make direct observations of planets, stars and galaxies, and analyze the data, theoretical astronomers create and investigate models of things that cannot be observed. They use this data to create models or simulations to theorize how different celestial bodies work, there are further subcategories inside these two main branches of astronomy such as planetary astronomy, galactic astronomy or physical cosmology. Today, that distinction has disappeared and the terms astronomer. Professional astronomers are highly educated individuals who typically have a Ph. D. in physics or astronomy and are employed by research institutions or universities. They spend the majority of their time working on research, although quite often have other duties such as teaching, building instruments. The number of astronomers in the United States is actually quite small. The American Astronomical Society, which is the organization of professional astronomers in North America, has approximately 7,000 members. This number includes scientists from other such as physics, geology. The International Astronomical Union comprises almost 10,145 members from 70 different countries who are involved in research at the Ph. D. level. Before CCDs, photographic plates were a method of observation. Modern astronomers spend relatively little time at telescopes usually just a few weeks per year, analysis of observed phenomena, along with making predictions as to the causes of what they observe, takes the majority of observational astronomers time. Astronomers who serve as faculty spend much of their time teaching undergraduate and graduate classes, most universities also have outreach programs including public telescope time and sometimes planetariums as a public service to encourage interest in the field. Those who become astronomers usually have a background in maths, sciences. Taking courses that teach how to research, write and present papers are also invaluable, in college/university most astronomers get a Ph. D. in astronomy or physics. Keeping in mind how few there are it is understood that graduate schools in this field are very competitive
9.
14P/Wolf
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14P/Wolf is a periodic comet in the Solar System. Max Wolf discovered the comet on September 17,1884 and it was later discovered, but not credited to, Ralph Copeland on September 23. The current values have been from when the comet passed Jupiter again on August 13,2005, another close approach to Jupiter on March 10,2041 will return the comet to parameters similar to the period 1925–2000. The comet nucleus is estimated to be 4.7 kilometers in diameter, 14P at Kronks Cometography 14P at Kazuo Kinoshitas Comets 14P at Seiichi Yoshidas Comet Catalog Orbital simulation from JPL / Horizons Ephemeris
10.
Doctor of Philosophy
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A Doctor of Philosophy is a type of doctoral degree awarded by universities in many countries. Ph. D. s are awarded for a range of programs in the sciences, engineering. The Ph. D. is a degree in many fields. The completion of a Ph. D. is often a requirement for employment as a university professor, researcher, individuals with an earned doctorate can use the title of Doctor with their name and use the post-nominal letters Ph. D. The requirements to earn a Ph. D. degree vary considerably according to the country, institution, a person who attains a doctorate of philosophy is automatically awarded the academic title of doctor. A student attaining this level may be granted a Candidate of Philosophy degree at some institutions. A Ph. D. candidate must submit a project, thesis or dissertation often consisting of a body of academic research. In many countries, a candidate must defend this work before a panel of examiners appointed by the university. Universities award other types of doctorates besides the Ph. D. such as the Doctor of Musical Arts, a degree for music performers and the Doctor of Education, in 2016, ELIA launched The Florence Principles on the Doctorate in the Arts. The Florence Principles have been endorsed are supported also by AEC, CILECT, CUMULUS, the degree is abbreviated PhD, from the Latin Philosophiae Doctor, pronounced as three separate letters. In the universities of Medieval Europe, study was organized in four faculties, the faculty of arts. All of these faculties awarded intermediate degrees and final degrees, the doctorates in the higher faculties were quite different from the current Ph. D. degree in that they were awarded for advanced scholarship, not original research. No dissertation or original work was required, only lengthy residency requirements, besides these degrees, there was the licentiate. According to Keith Allan Noble, the first doctoral degree was awarded in medieval Paris around 1150, the doctorate of philosophy developed in Germany as the terminal Teachers credential in the 17th century. Typically, upon completion, the candidate undergoes an oral examination, always public, starting in 2016, in Ukraine Doctor of Philosophy is the highest education level and the first science degree. PhD is awarded in recognition of a contribution to scientific knowledge. A PhD degree is a prerequisite for heading a university department in Ukraine, upon completion of a PhD, a PhD holder can elect to continue his studies and get a post-doctoral degree called Doctor of Sciences, which is the second and the highest science degree in Ukraine. Scandinavian countries were among the early adopters of a known as a doctorate of philosophy
11.
Astrophysics
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Astrophysics is the branch of astronomy that employs the principles of physics and chemistry to ascertain the nature of the heavenly bodies, rather than their positions or motions in space. Among the objects studied are the Sun, other stars, galaxies, extrasolar planets, the interstellar medium and their emissions are examined across all parts of the electromagnetic spectrum, and the properties examined include luminosity, density, temperature, and chemical composition. In practice, modern astronomical research often involves an amount of work in the realms of theoretical and observational physics. Although astronomy is as ancient as recorded history itself, it was separated from the study of terrestrial physics. Their challenge was that the tools had not yet been invented with which to prove these assertions, for much of the nineteenth century, astronomical research was focused on the routine work of measuring the positions and computing the motions of astronomical objects. Kirchhoff deduced that the lines in the solar spectrum are caused by absorption by chemical elements in the Solar atmosphere. In this way it was proved that the elements found in the Sun. Among those who extended the study of solar and stellar spectra was Norman Lockyer and he thus claimed the line represented a new element, which was called helium, after the Greek Helios, the Sun personified. By 1890, a catalog of over 10,000 stars had been prepared that grouped them into thirteen spectral types, most significantly, she discovered that hydrogen and helium were the principal components of stars. This discovery was so unexpected that her dissertation readers convinced her to modify the conclusion before publication, however, later research confirmed her discovery. By the end of the 20th century, studies of astronomical spectra had expanded to cover wavelengths extending from radio waves through optical, x-ray and it is the practice of observing celestial objects by using telescopes and other astronomical apparatus. The majority of observations are made using the electromagnetic spectrum. Radio astronomy studies radiation with a greater than a few millimeters. The study of these waves requires very large radio telescopes, infrared astronomy studies radiation with a wavelength that is too long to be visible to the naked eye but is shorter than radio waves. Infrared observations are made with telescopes similar to the familiar optical telescopes. Objects colder than stars are studied at infrared frequencies. Optical astronomy is the oldest kind of astronomy, telescopes paired with a charge-coupled device or spectroscopes are the most common instruments used. The Earths atmosphere interferes somewhat with optical observations, so adaptive optics, in this wavelength range, stars are highly visible, and many chemical spectra can be observed to study the chemical composition of stars, galaxies and nebulae
12.
Refracting telescope
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A refracting telescope is a type of optical telescope that uses a lens as its objective to form an image. The refracting telescope design was used in spy glasses and astronomical telescopes but is also used for long focus camera lenses. A refractors magnification is calculated by dividing the length of the objective lens by that of the eyepiece. Refractors were the earliest type of optical telescope, Galileo Galilei, happening to be in Venice in about the month of May 1609, heard of the invention and constructed a version of his own. Galileo then communicated the details of his invention to the public, all refracting telescopes use the same principles. The objective in a refracting telescope refracts or bends light and this refraction causes parallel light rays to converge at a focal point, while those not parallel converge upon a focal plane. The telescope converts a bundle of rays to make an angle α. The ratio β/α is called the angular magnification and it equals the ratio between the retinal image sizes obtained with and without the telescope. Refracting telescopes can come in different configurations to correct for image orientation. Because the image was formed by the bending of light, or refraction, the design Galileo Galilei used in 1609 is commonly called a Galilean telescope. It used a convergent objective lens and a divergent eyepiece lens, a Galilean telescope, because the design has no intermediary focus, results in a non-inverted and upright image. Galileo’s best telescope magnified objects about 30 times, because of flaws in its design, such as the shape of the lens and the narrow field of view, the images were blurry and distorted. Despite these flaws, the telescope was still enough for Galileo to explore the sky. The Galilean telescope could view the phases of Venus, and was able to see craters on the Moon, parallel rays of light from a distant object would be brought to a focus in the focal plane of the objective lens. The eyepiece lens intercepts these rays and renders them parallel once more, non-parallel rays of light from the object traveling at an angle α1 to the optical axis travel at a larger angle after they passed through the eyepiece. This leads to an increase in the apparent angular size and is responsible for the perceived magnification, the final image is a virtual image, located at infinity and is the same way up as the object. The Keplerian telescope, invented by Johannes Kepler in 1611, is an improvement on Galileos design and it uses a convex lens as the eyepiece instead of Galileos concave one. The advantage of this arrangement is that the rays of light emerging from the eyepiece are converging and this allows for a much wider field of view and greater eye relief, but the image for the viewer is inverted
13.
John Brashear
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Dr. John Alfred Brashear was an American astronomer and instrument builder. Brashear was born in Brownsville, Pennsylvania, a town 35 miles south of Pittsburgh along the Monongahela River and his father, Basil Brown Brashear, was a saddler, and his mother, Julia Smith Brashear, was a school teacher. He was the oldest of seven children, as a boy, John Brashear was heavily influenced by his maternal grandfather, Nathanial Smith, a clock repairer. When he was nine, his grandfather took him to view through the telescope of Squire Joseph P. Wampler and that influential view of the moon and the planet Saturn stayed with Brashear for the rest of his life. After receiving a school education until age 15, he became an apprentice to a machinist and had mastered his trade at age 20. Beginning in 1861 Brashear worked as a millwright in a steel mill in Pittsburgh. He pursued his love for astronomy at night, with the help of his wife Phoebe Stewart, of too little means to purchase a telescope, Brashear built his own workshop from a three-meter-square coal shed behind his house and proceeded to build his own refractor. Starting in 1880, he dedicated his time to manufacture astronomical as well as scientific instruments and he developed an improved silvering method, which would become the standard for coating first surface mirrors until vacuum metalizing began replacing it in 1932. Brashear patented few instruments and never patented his techniques and he founded John A. Brashear Co. with his son-in-law and partner, James Brown McDowell. Optical elements and instruments of precision produced by John Brashear were purchased for their quality by almost every important observatory in the world, some are still in use today. A crew demolishing his factory found a capsule that became an object of dispute. In 1892 Brashear made his second of three trips to Europe, this providing an lecture tour. In 1898 he became director of the Allegheny Observatory in Pittsburgh, from 1901 to 1904, he was acting chancellor of the Western University of Pennsylvania, now known as the University of Pittsburgh, after serving as a member of the board of trustees since 1896. Brashear also was a trustee of the Carnegie Institute of Technology and served as President of the Academy of Science, John and Phoebe Brashear were active in their church as well. He served as the director of Bingham Street Methodist Episcopal Church. The telescope is still in use today at Chabot Space and Science Center at Oakland, John Brashear was admired and beloved by fellow western Pennsylvanians and international astronomers, who familiarly called him Uncle John. In 1919, he suffered ptomaine poisoning, which induced a debilitating illness lasting six months and he died at age 79 at his South Side home. His body was held in state in the Great Hall of the Soldiers and Sailors Monument and his ashes are interred in a crypt below the Keeler Telescope at Allegheny Observatory, along with those of his wife
14.
Astrograph
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An astrograph is a telescope designed for the sole purpose of astrophotography. Astrographs are usually used in wide field surveys of the sky as well as detection of objects such as asteroids, meteors. Most research telescopes in this class are refractors, although there are many reflecting designs such as the Ritchey-Chrétien, the main parameters of an Astrograph are the diameter and f-ratio of the objective, which determine the field of view and image scale on the photographic plate or CCD detector. The objective of an astrograph is usually not very large, on the order of 20 to 50 cm, the shape of the focal plane is often designed to work in conjunction with a specific shaped photographic plate or CCD detector. The objective is designed to produce a large, flat. They may even be designed to certain wavelengths of light to match the type of film they are designed to use. Wide-angle astrographs with short f-ratios are used for photographing a huge area of sky, astrographs with higher f-ratios are used in more precise measurements. Many observatories of the world are equipped with the so-called normal astrographs with an aperture of around 13 inches, the purpose of a normal astrograph is to create images where the scale of the image at the focal plane is a standard of approximately 60 arcsecs/mm. Astrographs used in astrometry record images that are used to map the positions of objects over a large area of the sky. These maps are published in catalogs to be used in further study or to serve as reference points for deep-space imaging. Astrographs used for stellar classification sometimes consist of two telescopes on the same mount. Each sky field can be photographed in two colors. Each telescope may have individually designed non-achromatic objectives to focus the desired wavelength of light which is paired with the respective color-sensitive photographic plate. In other cases a single telescope is used to make two exposures of the part of the sky with different filters and color sensitive film used on each exposure. Two-color photography lets astronomers measure the color, as well as the brightness, knowing the color type and magnitudes lets astronomers determine the distance of a star. Sky fields that are photographed twice, decades apart in time, by taking two exposures of the same section of the sky days or weeks apart, it is possible to find objects such as asteroids, meteors, comets, variable stars, novae, and even unknown planets. Sometimes objects can even be found in one exposure since a fast moving object appear as a line in a long exposure. One well-known case of a used in a discovery is Clyde Tombaugh’s discovery of the dwarf planet Pluto in 1930
15.
F-number
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The f-number of an optical system such as a camera lens is the ratio of the systems focal length to the diameter of the entrance pupil. It is a number that is a quantitative measure of lens speed. It is also known as the ratio, f-ratio, f-stop. The f-number is commonly indicated using a hooked f with the format f/N, the f-number N or f# is given by, N = f D where f is the focal length, and D is the diameter of the entrance pupil. It is customary to write f-numbers preceded by f/, which forms a mathematical expression of the pupil diameter in terms of f and N. Ignoring differences in light transmission efficiency, a lens with a greater f-number projects darker images, the brightness of the projected image relative to the brightness of the scene in the lenss field of view decreases with the square of the f-number. Doubling the f-number decreases the brightness by a factor of four. To maintain the same photographic exposure when doubling the f-number, the time would need to be four times as long. Most lenses have a diaphragm, which changes the size of the aperture stop. The entrance pupil diameter is not necessarily equal to the aperture stop diameter, a 100 mm focal length f/4 lens has an entrance pupil diameter of 25 mm. A200 mm focal length f/4 lens has a pupil diameter of 50 mm. The 200 mm lenss entrance pupil has four times the area of the 100 mm lenss entrance pupil, a T-stop is an f-number adjusted to account for light transmission efficiency. The word stop is sometimes confusing due to its multiple meanings, a stop can be a physical object, an opaque part of an optical system that blocks certain rays. In photography, stops are also a used to quantify ratios of light or exposure. The one-stop unit is known as the EV unit. On a camera, the setting is traditionally adjusted in discrete steps. Each stop is marked with its corresponding f-number, and represents a halving of the light intensity from the previous stop. This corresponds to a decrease of the pupil and aperture diameters by a factor of 1/2 or about 0.7071, each element in the sequence is one stop lower than the element to its left, and one stop higher than the element to its right
16.
Reflecting telescope
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A reflecting telescope is an optical telescope which uses a single or combination of curved mirrors that reflect light and form an image. The reflecting telescope was invented in the 17th century as an alternative to the telescope which. Although reflecting telescopes produce other types of aberrations, it is a design that allows for very large diameter objectives. Almost all of the telescopes used in astronomy research are reflectors. Reflecting telescopes come in many 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 referred to as a catoptric telescope. The idea that curved mirrors behave like lenses dates back at least to Alhazens 11th century treatise on optics, 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 a design for a ‘reflecting’ telescope in 1663. It would be ten years, before the experimental scientist Robert Hooke was able to build this type of 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 diagonal mirror in an optical configuration that has come to be known as the Newtonian telescope. A curved primary mirror is the reflector telescopes basic optical element that creates an image at the focal plane, the distance from the mirror to the focal plane is called the focal length. The primary mirror in most modern telescopes is composed of a glass cylinder whose front surface has been ground to a spherical or parabolic shape. A thin layer of aluminum is deposited onto the mirror. Some telescopes use primary mirrors which are made differently, molten glass is rotated to make its surface paraboloidal, and is kept rotating while it cools and solidifies. The resulting mirror shape approximates a desired paraboloid shape that requires grinding and polishing to reach the exact figure needed. Reflecting telescopes, just like any other system, do not produce perfect images. The use of mirrors avoids chromatic aberration but they produce other types of aberrations, to avoid this problem most reflecting telescopes use parabolic shaped mirrors, a shape that can focus all the light to a common focus. Field curvature - The best image plane is in general curved and it is sometimes corrected by a field flattening lens
17.
Carl Zeiss AG
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Carl Zeiss is a German manufacturer of optical systems, industrial measurements and medical devices, founded in Jena, Germany in 1846 by optician Carl Zeiss. Together with Ernst Abbe and Otto Schott they built a base for modern optics, there are currently two parts of the company, Carl Zeiss AG located in Oberkochen with important subsidiaries in Aalen, Göttingen and Munich, and Carl Zeiss GmbH located in Jena. Carl Zeiss AG is the company of the Zeiss Gruppe. The Zeiss Gruppe is located in Heidenheim and Jena, also controlled by the Carl-Zeiss-Stiftung are the glass manufacturers Schott AG and Jenaer Glas, located in Mainz and Jena respectively. Carl Zeiss is one of the oldest existing optics manufacturers in the world, Carl Zeiss opened an optics workshop in Jena in 1846. By 1847 he was making microscopes full-time, by 1861 Zeiss was considered to be among the best scientific instrument makers in Germany with about 20 people working under him with his business still growing. By 1866 the Zeiss workshop sold their 1, 000th microscope, in 1872 physicist Ernst Abbe joined Zeiss and along with Otto Schott designed greatly improved lenses for the optical instruments they were producing. After Carl Zeisss death in 1888, the business was incorporated as the Carl-Zeiss-Stiftung in 1889, by World War I, Zeiss was the worlds largest location of camera production. Zeiss Ikon represented a significant part of the production along with dozens of brands and factories. The Hensoldt System Technology division was continued by Zeiss under the Hensoldt name until 2006, as part of Nazi Germany Zwangsarbeiter program, Zeiss used forced labour during the Second World War. The destruction of the war caused many companies to divide into smaller subcompanies, at the end of the war Jena was occupied by the US Army. As part of the World War II reparations, the Soviet army took most of the existing Zeiss factories and tooling back to the Soviet Union as the Kiev camera works. The western business was restarted in Oberkochen as Opton Optische Werke Oberkochen GmbH in 1946, which became Zeiss-Opton Optische Werke Oberkochen GmbH in 1947, but was soon renamed to Carl Zeiss. West German Zeiss products were labelled Opton for sale in the Eastern bloc and this collaboration continued under Yashicas successor, Kyocera, until the latter ceased all camera production in 2005. Zeiss later produced lenses for the industry and, more recently, has again produced high-quality 35 mm camera lenses. Jenoptik GmbH was split off as a specialty company in the areas of photonics, optoelectronics, the Hensoldt AG was renamed Carl Zeiss Sports Optics GmbH on 1 October 2006. The companies of the Zeiss Gruppe in and around Dresden have branched into new technologies, screens and products for the automotive industry, today, there are arguably three companies with primarily Zeiss Ikon heritage, Zeiss Germany, the Finnish/Swedish Ikon, and the independent eastern Zeiss Ikon. On 28 June 2013, Carl Zeiss officially announced its plan to rename the brand from Carl Zeiss to simply Zeiss, all the products will be standardized under the Zeiss brand
18.
Planetarium
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A planetarium is a theatre built primarily for presenting educational and entertaining shows about astronomy and the night sky, or for training in celestial navigation. Whatever technologies are used, the objective is normally to link together to provide an accurate relative motion of the sky. Typical systems can be set to display the sky at any point in time, past or present, planetaria range in size from the Hayden Planetariums 21-meter dome seating 423 people, to three-meter inflatable portable domes where children sit on the floor. Such portable planetaria serve education programs outside of the permanent installations of museums, the term planetarium is sometimes used generically to describe other devices which illustrate the solar system, such as a computer simulation or an orrery. Planetarium software refers to an application that renders a three-dimensional image of the sky onto a two-dimensional computer screen. The term planetarian is used to describe a member of the staff of a planetarium. The ancient Greek polymath Archimedes is attributed with creating a primitive device that could predict the movements of the Sun and the Moon. The discovery of the Antikythera mechanism proved that such devices already existed during antiquity, campanus of Novara described a planetary equatorium in his Theorica Planetarum, and included instructions on how to build one. The Globe of Gottorf built around 1650 had constellations painted on the inside and these devices would today usually be referred to as orreries. In fact, many planetaria today have what are called projection orreries, the small size of typical 18th century orreries limited their impact, and towards the end of that century a number of educators attempted some larger scale simulations of the heavens. The efforts of Adam Walker and his sons are noteworthy in their attempts to fuse theatrical illusions with educational aspirations, walkers Eidouranion was the heart of his public lectures or theatrical presentations. Every Planet and Satellite seems suspended in space, without any support and these devices most probably sacrificed astronomical accuracy for crowd-pleasing spectacle and sensational and awe-provoking imagery. The oldest, still working planetarium can be found in the Dutch town Franeker and it was built by Eise Eisinga in the living room of his house. It took Eisinga seven years to build his planetarium, which was completed in 1781 and this was displayed at the Deutsches Museum in 1924, construction work having been interrupted by the war. The planets travelled along overhead rails, powered by electric motors,180 stars were projected onto the wall by electric bulbs. Atwoods work at the Chicago Academy of Sciences and by the ideas of Walther Bauersfeld, in August 1923, the first Zeiss planetarium projected images of the night sky onto the white plaster lining of a 16 m hemispherical concrete dome, erected on the roof of the Zeiss works. The first official public showing was at the Deutsches Museum in Munich on October 21,1923, when Germany was divided into East and West Germany after the war, the Zeiss firm was also split. Part remained in its headquarters at Jena, in East Germany
19.
World War I
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World War I, also known as the First World War, the Great War, or the War to End All Wars, was a global war originating in Europe that lasted from 28 July 1914 to 11 November 1918. More than 70 million military personnel, including 60 million Europeans, were mobilised in one of the largest wars in history and it was one of the deadliest conflicts in history, and paved the way for major political changes, including revolutions in many of the nations involved. The war drew in all the worlds great powers, assembled in two opposing alliances, the Allies versus the Central Powers of Germany and Austria-Hungary. These alliances were reorganised and expanded as more nations entered the war, Italy, Japan, the trigger for the war was the assassination of Archduke Franz Ferdinand of Austria, heir to the throne of Austria-Hungary, by Yugoslav nationalist Gavrilo Princip in Sarajevo on 28 June 1914. This set off a crisis when Austria-Hungary delivered an ultimatum to the Kingdom of Serbia. Within weeks, the powers were at war and the conflict soon spread around the world. On 25 July Russia began mobilisation and on 28 July, the Austro-Hungarians declared war on Serbia, Germany presented an ultimatum to Russia to demobilise, and when this was refused, declared war on Russia on 1 August. Germany then invaded neutral Belgium and Luxembourg before moving towards France, after the German march on Paris was halted, what became known as the Western Front settled into a battle of attrition, with a trench line that changed little until 1917. On the Eastern Front, the Russian army was successful against the Austro-Hungarians, in November 1914, the Ottoman Empire joined the Central Powers, opening fronts in the Caucasus, Mesopotamia and the Sinai. In 1915, Italy joined the Allies and Bulgaria joined the Central Powers, Romania joined the Allies in 1916, after a stunning German offensive along the Western Front in the spring of 1918, the Allies rallied and drove back the Germans in a series of successful offensives. By the end of the war or soon after, the German Empire, Russian Empire, Austro-Hungarian Empire, national borders were redrawn, with several independent nations restored or created, and Germanys colonies were parceled out among the victors. During the Paris Peace Conference of 1919, the Big Four imposed their terms in a series of treaties, the League of Nations was formed with the aim of preventing any repetition of such a conflict. This effort failed, and economic depression, renewed nationalism, weakened successor states, and feelings of humiliation eventually contributed to World War II. From the time of its start until the approach of World War II, at the time, it was also sometimes called the war to end war or the war to end all wars due to its then-unparalleled scale and devastation. In Canada, Macleans magazine in October 1914 wrote, Some wars name themselves, during the interwar period, the war was most often called the World War and the Great War in English-speaking countries. Will become the first world war in the sense of the word. These began in 1815, with the Holy Alliance between Prussia, Russia, and Austria, when Germany was united in 1871, Prussia became part of the new German nation. Soon after, in October 1873, German Chancellor Otto von Bismarck negotiated the League of the Three Emperors between the monarchs of Austria-Hungary, Russia and Germany
20.
Deutsches Museum
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The museum was founded on 28 June 1903, at a meeting of the Association of German Engineers as an initiative of Oskar von Miller. Its official name is Deutsches Museum von Meisterwerken der Naturwissenschaft und Technik and it is the largest museum in Munich. The main site of the Deutsches Museum is an island in the Isar river. The island did not have any buildings before 1772 because it was regularly flooded prior to the building of the Sylvensteinspeicher, in 1772 the Isar barracks were built on the island and, after the flooding of 1899, the buildings were rebuilt with flood protection. In 1903 the city announced that they would donate the island for the newly built Deutsches Museum. The island formerly known as Kohleninsel was then renamed Museumsinsel, in addition to the main site on the Museumsinsel, the museum has two branches in and near Munich and one in Bonn. The Flugwerft Schleißheim branch is located some 18 kilometres north of Munichs city centre close to Schleißheim Palace and it is based on the premises of one of the first military airbases in Germany founded just before World War I. The Flugwerft Schleißheim displays various interesting airplanes for which there was insufficient room at the Museumsinsel site in downtown Munich, among the more prominent exhibits is a Horten flying wing glider built in the 1940s, restored from the few surviving parts. A collection of the German constructions of VTOL planes developed in the 1950s and 1960s is unique, a range of Vietnam era fighter planes as well as Russian planes taken over from East Germany after the reunification are on display. This outstation also features a dedicated to the restoration of all types of airplanes intended for static display. The latest branch of the Deutsches Museum, located at Theresienhöhe in Munich, the branch located in Bonn was opened in 1995 and focuses on German technology, science and research after 1945. In 1883 he joined AEG and founded an office in Munich. The Frankfurt electricity exhibition in 1891 and several power plants contributed to the reputation of Oskar von Miller, in the early years, the exhibition and the collection of the Deutsches Museum were strongly influenced personally by Oskar von Miller. A few months before the 1903 meeting of the Society of German Engineers, Oskar von Miller gathered a group who supported his desire to found a science. In a showing of support this group spontaneously donated 260,000 marks to the cause, in June 1903, Prince Ludwig agreed to act as patron of the museum and the city of Munich donated Coal Island as a site for the project. In addition, exhibits began to arrive from Munich, Germany, as no dedicated museum building existed, the exhibits were displayed in the National Museum. On 12 November 1906, the exhibits at the National Museum were ceremonially opened to the public. Oskar von Miller opened the new museum on his 70th birthday,2 May 1925, from the beginning, the museum displays are backed up by documents available in a public library and archives, which are open seven days a week to ensure access to the working public
21.
Munich
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Munich is the capital and largest city of the German state of Bavaria, on the banks of River Isar north of the Bavarian Alps. Munich is the third largest city in Germany, after Berlin and Hamburg, the Munich Metropolitan Region is home to 5.8 million people. According to the Globalization and World Rankings Research Institute Munich is considered an alpha-world city, the name of the city is derived from the Old/Middle High German term Munichen, meaning by the monks. It derives from the monks of the Benedictine order who ran a monastery at the place that was later to become the Old Town of Munich, Munich was first mentioned in 1158. From 1255 the city was seat of the Bavarian Dukes, black and gold—the colours of the Holy Roman Empire—have been the citys official colours since the time of Ludwig the Bavarian, when it was an imperial residence. Following a final reunification of the Wittelsbachian Duchy of Bavaria, previously divided and sub-divided for more than 200 years, like wide parts of the Holy Roman Empire, the area recovered slowly economically. In 1918, during the German Revolution, the house of Wittelsbach, which governed Bavaria since 1180, was forced to abdicate in Munich. In the 1920s, Munich became home to political factions, among them the NSDAP. During World War II, Munich was heavily bombed and more than 50% of the entire city, the postwar period was characterised by American occupation until 1949 and a strong increase of population and economic power during the years of the Wirtschaftswunder after 1949. The city is home to corporations like BMW, Siemens, MAN, Linde, Allianz and MunichRE as well as many small. Munich is home to national and international authorities, major universities, major museums. Its numerous architectural attractions, international events, exhibitions and conferences. Munich is one of the most prosperous and fastest growing cities in Germany and it is a top-ranked destination for migration and expatriate location, despite being the municipality with the highest density of population in Germany. Munich nowadays hosts more than 530,000 people of foreign background, the year 1158 is assumed to be the foundation date, which is the earliest date the city is mentioned in a document. The document was signed in Augsburg, by that time the Guelph Henry the Lion, Duke of Saxony and Bavaria, had built a bridge over the river Isar next to a settlement of Benedictine monks—this was on the Old Salt Route and a toll bridge. In 1175, Munich was officially granted city status and received fortification, in 1180, with the trial of Henry the Lion, Otto I Wittelsbach became Duke of Bavaria and Munich was handed over to the Bishop of Freising. In 1240, Munich was transferred to Otto II Wittelsbach and in 1255, Duke Louis IV, a native of Munich, was elected German king in 1314 and crowned as Holy Roman Emperor in 1328. He strengthened the position by granting it the salt monopoly
22.
Edward Emerson Barnard
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Edward Emerson Barnard was an American astronomer. He was commonly known as E. E. Barnard, and was recognized as an observational astronomer. He is best known for his discovery of the proper motion of Barnards Star in 1916. Barnard was born in Nashville, Tennessee, to Reuben Barnard and Elizabeth Jane Barnard and his father died three months before his birth, so he grew up in an impoverished family and did not receive much in the way of formal education. His first interest was in the field of photography, and he became an assistant at the age of nine. He later developed an interest in astronomy, in 1876 he purchased a 5-inch refractor telescope, and in 1881 he discovered his first comet, but failed to announce his discovery. He found his second later the same year and a third in 1882. While he was working at a photography studio he was married to the English-born woman Rhoda Calvert in 1881. In the 1880s, Hulbert Harrington Warner offered US$200 per discovery of a new comet, Edward discovered a total of five, and used the money to build a house for himself and his bride. With his name being brought to the attention of astronomers in Nashville. Barnard never graduated from the school, but he did receive the honorary degree Vanderbilt has ever awarded. In 1889 he observed the moon Iapetus pass behind Saturns rings, as he watched Iapetus pass through the space between Saturns innermost rings and the planet itself, he saw a shadow pass over the moon. Although he did not realise it at the time, he had discovered proof of the spokes of Saturn and these spokes were doubted at first, but confirmed by the spacecraft Voyager 1. In 1892 he made observations of a nova and was the first to notice the gaseous emissions, the same year he also discovered Amalthea, the fifth moon of Jupiter. He was the first to discover a new moon of Jupiter since Galileo Galilei in 1609 and this was the last satellite discovered by visual observation. In 1895 he joined the University of Chicago as professor of astronomy, there he was able to use the 40-inch telescope at Yerkes Observatory. Much of his work during this period was taking photographs of the Milky Way, together with Max Wolf, he discovered that certain dark regions of the galaxy were actually clouds of gas and dust that obscured the more distant stars in the background. From 1905, his niece Mary R. Calvert worked as his assistant, the faint Barnards Star is named for Edward Barnard after he discovered in 1916 that it had a very large proper motion, relative to other stars
23.
Comet
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A comet is an icy small Solar System body that, when passing close to the Sun, warms and begins to evolve gasses, a process called outgassing. This produces an atmosphere or coma, and sometimes also a tail. These phenomena are due to the effects of radiation and the solar wind acting upon the nucleus of the comet. Comet nuclei range from a few hundred metres to tens of kilometres across and are composed of collections of ice, dust. The coma may be up to 15 times the Earths diameter, if sufficiently bright, a comet may be seen from the Earth without the aid of a telescope and may subtend an arc of 30° across the sky. Comets have been observed and recorded since ancient times by many cultures, Comets usually have highly eccentric elliptical orbits, and they have a wide range of orbital periods, ranging from several years to potentially several millions of years. Short-period comets originate in the Kuiper belt or its associated scattered disc, long-period comets are thought to originate in the Oort cloud, a spherical cloud of icy bodies extending from outside the Kuiper belt to halfway to the nearest star. Long-period comets are set in motion towards the Sun from the Oort cloud by gravitational perturbations caused by passing stars, hyperbolic comets may pass once through the inner Solar System before being flung to interstellar space. The appearance of a comet is called an apparition, Comets are distinguished from asteroids by the presence of an extended, gravitationally unbound atmosphere surrounding their central nucleus. This atmosphere has parts termed the coma and the tail, however, extinct comets that have passed close to the Sun many times have lost nearly all of their volatile ices and dust and may come to resemble small asteroids. Asteroids are thought to have a different origin from comets, having formed inside the orbit of Jupiter rather than in the outer Solar System, the discovery of main-belt comets and active centaur minor planets has blurred the distinction between asteroids and comets. As of November 2014 there are 5,253 known comets, however, this represents only a tiny fraction of the total potential comet population, as the reservoir of comet-like bodies in the outer Solar System is estimated to be one trillion. Roughly one comet per year is visible to the eye, though many of those are faint. Particularly bright examples are called Great Comets, the word comet derives from the Old English cometa from the Latin comēta or comētēs. That, in turn, is a latinisation of the Greek κομήτης, Κομήτης was derived from κομᾶν, which was itself derived from κόμη and was used to mean the tail of a comet. The astronomical symbol for comets is ☄, consisting of a disc with three hairlike extensions. The solid, core structure of a comet is known as the nucleus, cometary nuclei are composed of an amalgamation of rock, dust, water ice, and frozen gases such as carbon dioxide, carbon monoxide, methane, and ammonia. As such, they are described as dirty snowballs after Fred Whipples model
24.
43P/Wolf-Harrington
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43P/Wolf–Harrington is a periodic comet discovered on December 22,1924, by Max Wolf in Heidelberg, Germany. In 2019 it will pass within 0.065 AU of Jupiter, during the 1997 apparition the comet reached an apparent magnitude a little bit brighter than 12. The comet had an apparition in 2010, because during perihelion. The comet was not more favorably positioned in the sky until mid October 2010, the comet nucleus is estimated to be 3.6 kilometers in diameter. net 43P/Wolf-Harrington on 2011-Apr-13 C
25.
Halley's Comet
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Halleys Comet or Comet Halley, officially designated 1P/Halley, is a short-period comet visible from Earth every 75–76 years. Halley is the only known short-period comet that is visible to the naked eye from Earth. Halley last appeared in the parts of the Solar System in 1986. Halleys returns to the inner Solar System have been observed and recorded by astronomers since at least 240 BC, clear records of the comets appearances were made by Chinese, Babylonian, and medieval European chroniclers, but were not recognized as reappearances of the same object at the time. The comets periodicity was first determined in 1705 by English astronomer Edmond Halley, Comet Halley is commonly pronounced /ˈhæli/, rhyming with valley, or /ˈheɪli/, rhyming with daily. Spellings of Edmond Halleys name during his lifetime included Hailey, Haley, Hayley, Halley, Hawley, Halley was the first comet to be recognized as periodic. Until the Renaissance, the consensus on the nature of comets. This idea was disproved in 1577 by Tycho Brahe, who used parallax measurements to show that comets must lie beyond the Moon, many were still unconvinced that comets orbited the Sun, and assumed instead that they must follow straight paths through the Solar System. In 1687, Sir Isaac Newton published his Philosophiæ Naturalis Principia Mathematica, in which he outlined his laws of gravity and his work on comets was decidedly incomplete. Halley thus concluded that all three comets were, in fact, the same object returning every 76 years, a period that has since been amended to every 75–76 years. After a rough estimate of the perturbations the comet would sustain from the attraction of the planets. Halley died in 1742 before he could observe this himself, Halleys prediction of the comets return proved to be correct, although it was not seen until 25 December 1758, by Johann Georg Palitzsch, a German farmer and amateur astronomer. It did not pass through its perihelion until 13 March 1759 and this effect was computed prior to its return by a team of three French mathematicians, Alexis Clairaut, Joseph Lalande, and Nicole-Reine Lepaute. The confirmation of the return was the first time anything other than planets had been shown to orbit the Sun. It was also one of the earliest successful tests of Newtonian physics, the comet was first named in Halleys honour by French astronomer Nicolas Louis de Lacaille in 1759. Some scholars have proposed that first-century Mesopotamian astronomers already had recognized Halleys Comet as periodic and this theory notes a passage in the Bavli Talmud that refers to a star which appears once in seventy years that makes the captains of the ships err. It was necessary to use ancient Chinese comet observations to constrain their calculations, Halleys orbital period over the last 3 centuries has been between 75–76 years, although it has varied between 74–79 years since 240 BC. Its orbit around the Sun is highly elliptical, with an eccentricity of 0.967
26.
Dark nebula
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A dark nebula or absorption nebula is a type of interstellar cloud that is so dense that it obscures the light from objects behind it, such as background stars and emission or reflection nebulae. The extinction of the light is caused by interstellar dust grains located in the coldest, densest parts of molecular clouds. Clusters and large complexes of dark nebulae are associated with Giant Molecular Clouds, isolated small dark nebulae are called Bok globules. Like other interstellar dust or material, things it obscures are only visible using radio waves in radio astronomy or infrared in infrared astronomy. Dark clouds appear so because of sub-micrometre-sized dust particles, coated with carbon monoxide and nitrogen. Also present are molecular hydrogen, atomic helium, C18O, CS, NH3, H2CO, c-C3H2 and these clouds are the spawning grounds of stars and planets, and understanding their development is essential to understanding star formation. The form of dark clouds is very irregular, they have no clearly defined outer boundaries and sometimes take on convoluted serpentine shapes. The largest dark nebulae are visible to the eye, appearing as dark patches against the brighter background of the Milky Way like the Coalsack Nebula. These naked-eye objects are known as dark cloud constellations and take on a variety of names. In the inner outer molecular regions of dark nebulae, important events take place, list of dark nebulae Bok globule
27.
William Herschel
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Frederick William Herschel, KH, FRS was a British astronomer and composer of German origin, and brother of fellow astronomer Caroline Herschel, with whom he worked. Born in the Electorate of Hanover, Herschel followed his father into the Military Band of Hanover, Herschel constructed his first large telescope in 1774, after which he spent nine years carrying out sky surveys to investigate double stars. The resolving power of the Herschel telescopes revealed that the nebulae in the Messier catalogue were clusters of stars, Herschel published catalogues of nebulae in 1802 and in 1820. In the course of an observation on 13 March 1781, he realized that one celestial body he had observed was not a star and this was the first planet to be discovered since antiquity and Herschel became famous overnight. As a result of this discovery, George III appointed him Court Astronomer and he was elected as a Fellow of the Royal Society and grants were provided for the construction of new telescopes. Herschel pioneered the use of astronomical spectrophotometry as a tool, using prisms. Other work included a determination of the rotation period of Mars, the discovery that the Martian polar caps vary seasonally. In addition, Herschel discovered infrared radiation, Herschel was made a Knight of the Royal Guelphic Order in 1816. He was the first President of the Royal Astronomical Society when it was founded in 1820 and he died in August 1822, and his work was continued by his only son, John Herschel. Herschel was born in the Electorate of Hanover in Germany, then part of the Holy Roman Empire and his father was an oboist in the Hanover Military Band. In 1755 the Hanoverian Guards regiment, in whose band Wilhelm, at the time the crowns of Great Britain and Hanover were united under King George II. As the threat of war with France loomed, the Hanoverian Guards were recalled from England to defend Hanover, after they were defeated at the Battle of Hastenbeck, Herschels father Isaak sent his two sons to seek refuge in England in late 1757. Although his older brother Jakob had received his dismissal from the Hanoverian Guards, Wilhelm, nineteen years old at this time, was a quick student of the English language. In England he went by the English rendition of his name, in addition to the oboe, he played the violin and harpsichord and later the organ. He composed numerous works, including 24 symphonies and many concertos. Six of his symphonies were recorded in April 2002 by the London Mozart Players, Herschel moved to Sunderland in 1761 when Charles Avison immediately engaged him as first violin and soloist for his Newcastle orchestra, where he played for one season. In ‘Sunderland in the County of Durh, apprill 20th 1761’ he wrote his Symphony No.8 in C Minor. He was head of the Durham Militia band 1760–61 and visited the home of Sir Ralph Milbanke at Halnaby Hall in 1760, after Newcastle he moved to Leeds and Halifax where he was the first organist at St John the Baptist church
28.
Proper motion
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The components of proper motion in the equatorial coordinate system are measured in seconds of time for right ascension and seconds of arc in declination. Their combined value is computed as the proper motion, which is expressed in seconds of arc per year or per century. Knowledge of the motion, distance, and radial velocity allow approximate calculations of a stars true motion in space in respect to the Sun. Proper motion is not entirely proper, because it includes a component due to the motion of the Solar System itself, over the course of centuries, stars appear to maintain nearly fixed positions with respect to each other, so that they form the same constellations over historical time. Ursa Major or Crux, for example, looks nearly the same now as they did hundreds of years ago, however, precise long-term observations show that the constellations change shape, albeit very slowly, and that each star has an independent motion. This motion is caused by the movement of the relative to the Sun. The proper motion is a vector and is thus defined by two quantities, its position angle and its magnitude. The first quantity indicates the direction of the motion on the celestial sphere. Proper motion may alternatively be defined by the changes per year in the stars right ascension and declination. The components of motion by convention are arrived at as follows. Suppose in a year an object moves from coordinates to coordinates, then the changes of angle in seconds of arc per year are, The magnitude of the proper motion μ is given by vector addition of its components, where δ is the declination. The factor in cos δ accounts for the fact that the radius from the axis of the sphere to its surface varies as cos δ, becoming, for example, zero at the pole. Thus, the component of velocity parallel to the corresponding to a given angular change in α is smaller the further north the objects location. The change μα, which must be multiplied by cos δ to become a component of the motion, is sometimes called the proper motion in right ascension. Hence, the proper motions in right ascension and declination are made equivalent for straightforward calculations of various other stellar motions. Position angle θ is related to these components by, Motions in equatorial coordinates can be converted to motions in galactic coordinates, for the majority of stars seen in the sky, the observed proper motions are usually small and unremarkable. Such stars are either faint or are significantly distant, have changes of below 10 milliarcseconds per year. A few do have significant motions, and are usually called high-proper motion stars, Motions can also be in almost seemingly random directions
29.
Wolf 359
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Wolf 359 is a red dwarf that is located in the constellation Leo, near the ecliptic. At a distance of approximately 7.8 light years from Earth, it has an apparent magnitude of 13.5 and can only be seen with a large telescope. Wolf 359 is one of the nearest stars to the Sun, only the Alpha Centauri system, Barnards Star and its proximity to Earth has led to its mention in several works of fiction. Wolf 359 is one of the faintest and lowest-mass stars known, at the light-emitting layer called the photosphere, it has a temperature of about 2,800 K, which is low enough for chemical compounds to form and survive. The absorption lines of such as water and titanium oxide have been observed in the spectrum. The surface has a field that is stronger than the average magnetic field on the Sun. As a result of activity caused by convection, Wolf 359 is a flare star that can undergo sudden increases in luminosity for several minutes. These flares emit strong bursts of X-ray and gamma ray radiation that have been observed by space telescopes, Wolf 359 is a relatively young star with an age of less than a billion years. No companions or disks of debris have been detected in orbit around it, Wolf 359 first came to the attention of astronomers because of the relatively high rate of transverse motion against the background, known as the proper motion. The proper motion of Wolf 359 was first measured in 1917 by German astronomer Max Wolf, in 1919 he published a catalog of over one thousand stars with high proper motions, including this one, that are still identified by his name. He listed this star as entry number 359, and the star has since referred to as Wolf 359 in reference to Max Wolfs catalogue. The first parallax measurement of Wolf 359 was reported in 1928 from the Mount Wilson Observatory, from this position change, and the known size of the Earths orbit, the distance to the star could be estimated. It was the lowest-mass and faintest star known until the discovery of VB10 in 1944, the infrared magnitude of the star was measured in 1957. In 1969, a flare in the luminosity of Wolf 359 was observed. Wolf 359 has a classification of M6.5, although various sources list a spectral class of M5.5. An M-type star is known as a red dwarf, it is called red because the emission of the star reaches a peak in the red and infrared parts of the spectrum. Wolf 359 has a low luminosity, emitting about 0. 1% of the Suns energy. If it were moved to the location of the Sun, it would appear ten times as bright as the full Moon
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Barnard's Star
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Barnards Star /ˈbɑːrnərd/ is a very-low-mass red dwarf about six light-years away from Earth in the constellation of Ophiuchus. It is the fourth-closest known individual star to the Sun and the closest star in the Northern Hemisphere. Despite its proximity, at a dim apparent magnitude of about nine, it is not visible with the unaided eye, the star is named after the American astronomer E. E. Barnard. He was not the first to observe the star, but in 1916 he measured its proper motion as 10.3 arcseconds per year, in 2016, the International Astronomical Union organized a Working Group on Star Names to catalogue and standardize proper names for stars. The WGSN approved the name Barnards Star for this star on 1 February 2017, Barnards Star is among the most studied red dwarfs because of its proximity and favorable location for observation near the celestial equator. Historically, research on Barnards Star has focused on measuring its stellar characteristics, its astrometry, although Barnards Star is an ancient star, it still experiences star flare events, one being observed in 1998. The star has also been the subject of some controversy, for a decade, from the early 1960s to the early 1970s, Peter van de Kamp claimed that there were one or more gas giants in orbit around it. Although the presence of terrestrial planets around Barnards Star remains a possibility. Barnards Star is a red dwarf of the dim spectral type M4, at 7–12 billion years of age, Barnards Star is considerably older than the Sun, which is 4.5 billion years old, and it might be among the oldest stars in the Milky Way galaxy. Barnards Star has lost a great deal of energy. Given its age, Barnards Star was long assumed to be quiescent in terms of stellar activity, in 1998, astronomers observed an intense stellar flare, showing that Barnards Star is a flare star. Barnards Star has the variable star designation V2500 Ophiuchi, in 2003, Barnards Star presented the first detectable change in the radial velocity of a star caused by its motion. Further variability in the velocity of Barnards Star was attributed to its stellar activity. The proper motion of Barnards Star corresponds to a lateral speed of 90 km/s. The 10.3 seconds of arc it travels annually amount to a quarter of a degree in a human lifetime, the radial velocity of Barnards Star towards the Sun is measured from its blue shift to be 110 km/s. Combined with its motion, this gives a space velocity of 142.6 ±0.2 km/s. Barnards Star will make its closest approach to the Sun around AD11,800, proxima Centauri is the closest star to the Sun at a position currently 4.24 light-years distant from it. Barnards Star has a mass of about 0.14 solar masses, thus, although Barnards Star has roughly 150 times the mass of Jupiter, its radius is only 1.5 to 2.0 times larger, due to its much higher density
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Earth
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Earth, otherwise known as the World, or the Globe, is the third planet from the Sun and the only object in the Universe known to harbor life. It is the densest planet in the Solar System and the largest of the four terrestrial planets, according to radiometric dating and other sources of evidence, Earth formed about 4.54 billion years ago. Earths gravity interacts with objects in space, especially the Sun. During one orbit around the Sun, Earth rotates about its axis over 365 times, thus, Earths axis of rotation is tilted, producing seasonal variations on the planets surface. The gravitational interaction between the Earth and Moon causes ocean tides, stabilizes the Earths orientation on its axis, Earths lithosphere is divided into several rigid tectonic plates that migrate across the surface over periods of many millions of years. About 71% of Earths surface is covered with water, mostly by its oceans, the remaining 29% is land consisting of continents and islands that together have many lakes, rivers and other sources of water that contribute to the hydrosphere. The majority of Earths polar regions are covered in ice, including the Antarctic ice sheet, Earths interior remains active with a solid iron inner core, a liquid outer core that generates the Earths magnetic field, and a convecting mantle that drives plate tectonics. Within the first billion years of Earths history, life appeared in the oceans and began to affect the Earths atmosphere and surface, some geological evidence indicates that life may have arisen as much as 4.1 billion years ago. Since then, the combination of Earths distance from the Sun, physical properties, in the history of the Earth, biodiversity has gone through long periods of expansion, occasionally punctuated by mass extinction events. Over 99% of all species that lived on Earth are extinct. Estimates of the number of species on Earth today vary widely, over 7.4 billion humans live on Earth and depend on its biosphere and minerals for their survival. Humans have developed diverse societies and cultures, politically, the world has about 200 sovereign states, the modern English word Earth developed from a wide variety of Middle English forms, which derived from an Old English noun most often spelled eorðe. It has cognates in every Germanic language, and their proto-Germanic root has been reconstructed as *erþō, originally, earth was written in lowercase, and from early Middle English, its definite sense as the globe was expressed as the earth. By early Modern English, many nouns were capitalized, and the became the Earth. More recently, the name is simply given as Earth. House styles now vary, Oxford spelling recognizes the lowercase form as the most common, another convention capitalizes Earth when appearing as a name but writes it in lowercase when preceded by the. It almost always appears in lowercase in colloquial expressions such as what on earth are you doing, the oldest material found in the Solar System is dated to 4. 5672±0.0006 billion years ago. By 4. 54±0.04 Gya the primordial Earth had formed, the formation and evolution of Solar System bodies occurred along with the Sun
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Frank Elmore Ross
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Frank Elmore Ross was an American astronomer and physicist. He was born in San Francisco, California and died in Altadena, in 1901 he received his doctorate from the University of California. In 1905 he became director of the International Latitude Observatory station at Gaithersburg, in 1915 he became a physicist for Eastman Kodak Company at Rochester, New York. He accepted a position at the Yerkes Observatory in 1924 and worked there until his retirement in 1939 and his first important work was the calculation of the first reliable orbit of Saturns moon Phoebe in 1905, and he also calculated orbits for Jupiters satellites Himalia and Elara. When working for Eastman Kodak he investigated photographic emulsions and the design of lenses for astronomical use. At Yerkes Observatory he was the successor to the late E. E. Barnard, Ross decided to repeat the same series of images and compare the results with a blink comparator. In doing so, he discovered 379 new variable stars and over 1000 stars of high proper motion, some of the high–proper motion stars turned out to be quite nearby, and many of these stars are still widely known by the catalog number he gave them. During the opposition of Mars in 1926 he photographed the planet in different colors, the following year he obtained ultraviolet pictures of Venus, which showed structure in its cloud cover for the first time. The crater Ross on Mars is named after him, and the crater Ross on the Moon is jointly named after him and he was awarded the Franklin Institutes John Price Wetherill Medal in 1928. Obs 8176 PASP73 182–184 QJRAS2 276–278 National Academy of Sciences Biographical Memoir
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George Van Biesbroeck
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George A. Van Biesbroeck was a Belgian–American astronomer. He worked at observatories in Belgium, Germany and the United States and he specialized in the observation of double stars, asteroids and comets. He is notable for his career as an observational astronomer. He was born in Ghent, Belgium on January 21,1880 to a family of artists. At his fathers request he pursued, and in 1902, he received, but his true vocation is not there, it was astronomy, and while performing his official duties as a civil engineer he joined volunteers at the Uccle Observatory. In 1904 he left civil engineering behind and joined the staff at the Royal Observatory of Belgium at Uccle and he then enrolled at Ghent University and obtained a degree in theoretical astronomy. He worked at the Heidelberg Observatory, then at the Potsdam Observatory under the direction of Max Wolf, Karl Schwarzschild, in 1915, as World War I was raging, he was invited to come to work at Yerkes Observatory. He and his family made the trip across wartime Europe. He became a U. S citizen in 1922 and he then began his work on double stars, comets, asteroids, and variable stars. In 1945 he was forced into retirement at Yerkes at the age of 65, relieved of administrative duties, he became an even more active observer at Yerkes and at the McDonald Observatory. He made the frequent automobile trips between the observatories in Wisconsin and Texas without complaint and he participated in numerous physically grueling astronomical expeditions to remote parts of the world throughout the late 1940s and 1950s. His measurements were in agreement with Einsteins predictions and his travels to Sudan were the subject of a Time Magazine article. He discovered the periodic comet 53P/Van Biesbroeck, as well as two comets, C/1925 W1 and C/1935 Q1. He also discovered sixteen asteroids between 1922 and 1939, in 1961 he published the Van Biesbroecks star catalog. In this he cataloged a number of faint stars, known by the VB numbers he assigned to them upon discovery. One notable star he discovered was the small red dwarf secondary star, VB10, also known as Gliese 752B, of the primary star. This star was unique in that its magnitude of 19 was the lowest of any star then known. VB10 was given the designation of Van Biesbroecks Star to honor him for this work, in 1963 he came to the Lunar and Planetary Laboratory of the University of Arizona in Tucson Arizona to work under Gerard Kuiper
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Astronomical survey
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An astronomical survey is a general map or image of a region of the sky which lacks a specific observational target. Alternatively, a survey may comprise a set of many images or spectra of objects which share a common type or feature. Surveys have generally performed as part of the production of an astronomical catalog. In some cases, an interested in a particular object will find that survey images are sufficient to make telescope time entirely unnecessary. Surveys also help astronomers obtain observation time on larger, more powerful telescopes, if the astronomer can show a telescope scheduling committee that previous observations support his or her hypothesis, he or she is more likely to be given a chance to make more detailed observations. The wide scope of surveys makes them ideal for astronomers searching for moving objects such as asteroids. An astronomer can compare existing survey images to current observations to locate targets which are in motion, similarly, images of the same object taken by different surveys can be compared to detect transient events such as variable stars. It began in 1977 to 1982 then from 1985 to 1995.3,4.7,12, the telescope is over a thousand times as sensitive as previous infrared surveys. The initial survey, consisting of each sky position imaged at least eight times, was completed by July 2010, 1997–2002 Ohio Sky Survey – Over 19,000 radio sources at 1415 MHz. NVSS – Survey at 1.4 GHz mapping the sky north of −40 deg FIRST – Survey to look for faint radio sources at twenty cms, PALFA Survey – On-going 1.4 GHz survey for radio pulsars using the Arecibo Observatory. 2008–present, the goal for the lifetime is 10 years. The resulting dataset aims to be a resource for studying the physics of the galaxy population. GOODS – The Great Observatories Origins Deep Survey, COSMOS – The Cosmic Evolution Survey. Atlas 3d Survey – sample of 260 galaxies for the Astrophysics project, timeline of astronomical maps, catalogs, and surveys
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Asteroid
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Asteroids are minor planets, especially those of the inner Solar System. The larger ones have also been called planetoids and these terms have historically been applied to any astronomical object orbiting the Sun that did not show the disc of a planet and was not observed to have the characteristics of an active comet. As minor planets in the outer Solar System were discovered and found to have volatile-based surfaces that resemble those of comets, in this article, the term asteroid refers to the minor planets of the inner Solar System including those co-orbital with Jupiter. There are millions of asteroids, many thought to be the remnants of planetesimals. The large majority of known asteroids orbit in the belt between the orbits of Mars and Jupiter, or are co-orbital with Jupiter. However, other orbital families exist with significant populations, including the near-Earth objects, individual asteroids are classified by their characteristic spectra, with the majority falling into three main groups, C-type, M-type, and S-type. These were named after and are identified with carbon-rich, metallic. The size of asteroids varies greatly, some reaching as much as 1000 km across, asteroids are differentiated from comets and meteoroids. In the case of comets, the difference is one of composition, while asteroids are composed of mineral and rock, comets are composed of dust. In addition, asteroids formed closer to the sun, preventing the development of the aforementioned cometary ice, the difference between asteroids and meteoroids is mainly one of size, meteoroids have a diameter of less than one meter, whereas asteroids have a diameter of greater than one meter. Finally, meteoroids can be composed of either cometary or asteroidal materials, only one asteroid,4 Vesta, which has a relatively reflective surface, is normally visible to the naked eye, and this only in very dark skies when it is favorably positioned. Rarely, small asteroids passing close to Earth may be visible to the eye for a short time. As of March 2016, the Minor Planet Center had data on more than 1.3 million objects in the inner and outer Solar System, the United Nations declared June 30 as International Asteroid Day to educate the public about asteroids. The date of International Asteroid Day commemorates the anniversary of the Tunguska asteroid impact over Siberia, the first asteroid to be discovered, Ceres, was found in 1801 by Giuseppe Piazzi, and was originally considered to be a new planet. In the early half of the nineteenth century, the terms asteroid. Asteroid discovery methods have improved over the past two centuries. This task required that hand-drawn sky charts be prepared for all stars in the band down to an agreed-upon limit of faintness. On subsequent nights, the sky would be charted again and any moving object would, hopefully, the expected motion of the missing planet was about 30 seconds of arc per hour, readily discernible by observers
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Trojan (astronomy)
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In astronomy, a trojan is a minor planet or moon that shares the orbit of a planet or larger moon, wherein the trojan remains in the same, stable position relative to the larger object. In particular, a trojan remains near one of the two points of stability – designated L4 and L5 – which lie approximately 60° ahead of and behind the larger body. Trojan points make up two of five types of Lagrangian points, and a trojan is a type of Lagrangian object and they are one type of co-orbital object. In this arrangement, the star and the smaller planet orbit about their common barycenter. A much smaller mass located at one of the Lagrangian points is subject to a gravitational force that acts through this barycenter. Hence the object can orbit around the barycenter with the orbital period as the planet. The Jupiter trojans account for most known trojans in the Solar System and they are divided into the Greek camp in front of and the Trojan camp trailing behind Jupiter in their orbit. Numerical calculations of the dynamics involved indicate that Saturn and Uranus probably do not have any primordial trojans. The discovery of the first Earth trojan,2010 TK7, was announced by NASA in 2011, unlike trojan minor planets that share the orbit with a planet, a trojan moon is a moon orbiting near the trojan point of another, larger moon. All known trojan moons are part of the Saturn system, telesto and Calypso are trojans of Tethys, and Helene and Polydeuces of Dione. There is also a concept of a trojan planet, a planet that orbits at the trojan point of another, larger planet. Such a pair of co-orbital exoplanets was already thought to exist in another star system, in 1772, the Italian–French mathematician and astronomer Joseph-Louis Lagrange obtained two constant-pattern solutions of the general three-body problem. In the restricted problem, with one mass negligible, the five possible positions of that mass are now termed Lagrangian points. The term trojan originally referred to the asteroids that orbit close to the Lagrangian points of Jupiter. These have long been named after characters from the Trojan War of Greek mythology, there are two exceptions, which were named before the convention was put in place, the Greek-themed 617 Patroclus and the Trojan-themed 624 Hektor, which were assigned to the wrong sides. Astronomers estimate that the Jupiter trojans are about as numerous as the asteroids of the asteroid belt, later on, objects were found orbiting near the Lagrangian points of Neptune, Mars, Earth, Uranus, and Venus. Minor planets at the Lagrangian points of other than Jupiter may be called Lagrangian minor planets. 17 Neptune trojans are known, but large Neptune trojans are expected to outnumber the large Jupiter trojans by an order of magnitude,2010 TK7 was confirmed to be the first known Earth trojan in 2011
