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Sextant (astronomical)
In astronomy, sextants are devices depicting a sixth of a circle, used primarily for measuring the position of stars. There are two types of astronomical sextants, mural instruments and frame-based instruments. They are of significant historical importance, but have been replaced over time by transit telescopes, other astrometry techniques, and satellites such as Hipparcos. Mural sextants The first known mural sextant was constructed in Ray, Iran, by Abu-Mahmud al-Khujandi in 994. To measure the obliquity of the ecliptic, al-Khujandī invented a device that he called ''al-Fakhri sextant'' (al-suds al Fakhrī), a reference to his patron, Buwayhid ruler, Fakhr al Dawla (976–997). This instrument was a sixty-degree arc on a wall aligned along a meridian (north–south) line. Al Khujandi's instrument was larger than previous instruments; it had a radius of about twenty meters. Tekeli, Sevim (1958), 'Nasiruddin, Takiyuddin ve Tycho Brahe'nin Rasat Aletlerinin mukayesesi'. ''A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Astronomy
Astronomy () is a natural science that studies celestial objects and phenomena. It uses mathematics, physics, and chemistry in order to explain their origin and evolution. Objects of interest include planets, moons, stars, nebulae, galaxies, and comets. Relevant phenomena include supernova explosions, gamma ray bursts, quasars, blazars, pulsars, and cosmic microwave background radiation. More generally, astronomy studies everything that originates beyond Earth's atmosphere. Cosmology is a branch of astronomy that studies the universe as a whole. Astronomy is one of the oldest natural sciences. The early civilizations in recorded history made methodical observations of the night sky. These include the Babylonians, Greeks, Indians, Egyptians, Chinese, Maya, and many ancient indigenous peoples of the Americas. In the past, astronomy included disciplines as diverse as astrometry, celestial navigation, observational astronomy, and the making of calendars. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Summer Solstice
The summer solstice, also called the estival solstice or midsummer, occurs when one of Earth's poles has its maximum tilt toward the Sun. It happens twice yearly, once in each hemisphere (Northern and Southern). For that hemisphere, the summer solstice is the day with the longest period of daylight and shortest night of the year, when the Sun is at its highest position in the sky. Within the Arctic circle (for the Northern hemisphere) or Antarctic circle (for the Southern), there is continuous daylight around the summer solstice. The opposite event is the winter solstice. The summer solstice occurs during summer. This is the June solstice (usually 20 or 21 June) in the Northern hemisphere and the December solstice (usually 21 or 22 December) in the Southern. On the summer solstice, Earth's maximum axial tilt toward the Sun is 23.44°. Likewise, the Sun's declination from the celestial equator is 23.44°. Since prehistory, the summer solstice has been seen as a significant ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tycho Brahe
Tycho Brahe ( ; born Tyge Ottesen Brahe; generally called Tycho (14 December 154624 October 1601) was a Danish astronomer, known for his comprehensive astronomical observations, generally considered to be the most accurate of his time. He was known during his lifetime as an astronomer, astrologer, and alchemist. He was the last major astronomer before the invention of the telescope. An heir to several noble families, Tycho was well-educated. He took an interest in astronomy and in the creation of more accurate instruments of measurement. He worked to combine what he saw as the geometrical benefits of Copernican heliocentrism with the philosophical benefits of the Ptolemaic system, and devised the Tychonic system, his own version of a model of the universe, with the Sun orbiting the Earth, and the planets as orbiting the Sun. In ''De nova stella'' (1573), he refuted the Aristotelian belief in an unchanging celestial realm. His measurements indicated that "new stars" (''stel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Equinox
A solar equinox is a moment in time when the Sun crosses the Earth's equator, which is to say, appears directly above the equator, rather than north or south of the equator. On the day of the equinox, the Sun appears to rise "due east" and set "due west". This occurs twice each year, around 20 March and 23 September. More precisely, an equinox is traditionally defined as the time when the plane of Earth's equator passes through the geometric center of the Sun's disk. Equivalently, this is the moment when Earth's rotation axis is directly perpendicular to the Sun-Earth line, tilting neither toward nor away from the Sun. In modern times, since the Moon (and to a lesser extent the planets) causes Earth's orbit to vary slightly from a perfect ellipse, the equinox is officially defined by the Sun's more regular ecliptic longitude rather than by its declination. The instants of the equinoxes are currently defined to be when the apparent geocentric longitude of the Sun is 0° a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Taqi Al-Din Muhammad Ibn Ma'ruf
Taqi ad-Din Muhammad ibn Ma'ruf ash-Shami al-Asadi ( ar, تقي الدين محمد بن معروف الشامي; ota, تقي الدين محمد بن معروف الشامي السعدي; tr, Takiyüddin 1526–1585) was an Ottoman polymath active in Cairo and Istanbul. He was the author of more than ninety books on a wide variety of subjects, including astronomy, clocks, engineering, mathematics, mechanics, optics and natural philosophy. In 1574 the Ottoman Sultan Murad III invited Taqi ad-Din to build an observatory in the Ottoman capital, Istanbul. Using his exceptional knowledge in the mechanical arts, Taqi ad-Din constructed instruments like huge armillary and mechanical clocks that he used in his observations of the Great Comet of 1577. He also used European celestial and terrestrial globes that were delivered to Istanbul in gift exchanges. The major work that resulted from his work in the observatory is titled "The tree of ultimate knowledge n the end of time o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Elisabetha Hevelius
Elisabeth Catherina Koopmann-Hevelius (in Polish called ''Elżbieta Heweliusz''; January 17, 1647–December 22, 1693) is considered one of the first female astronomers. Originally from Danzig, Poland, she contributed to improve the work and observations done together with her husband Johannes Hevelius. Early life Elisabeth Koopmann (or Kaufmann, german: "merchant") was, like Hevelius and his first wife, a member of a rich merchant family in the city of Danzig ( Gdańsk) located in Pomeranian Voivodeship of the Polish–Lithuanian Commonwealth and a member of the trade organisation called Hansa. Elisabetha Koopman's parents were Nicholas Koopman (the Dutch word for "Merchant") (1601-1672) who was a prosperous merchant and Joanna Mennings (or Menninx) (1602-1679). Nicholas and Joanna were married in Amsterdam in 1633. They moved from Amsterdam to Hamburg then, in 1636, they moved to Danzig. It was in this city, largely German speaking but a part of Poland at the time, that their ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Graduation (instrument)
A graduation is a marking used to indicate points on a visual scale, which can be present on a container, a measuring device, or the axes of a line plot, usually one of many along a line or curve, each in the form of short line segments perpendicular to the line or curve. Often, some of these line segments are longer and marked with a numeral, such as every fifth or tenth graduation. The scale itself can be linear (the graduations are spaced at a constant distance apart) or nonlinear. Linear graduation of a scale occurs mainly (but not exclusively) on straight measuring devices, such as a rule or measuring tape, using units such as inches or millimetres. Graduations can also be spaced at varying spatial intervals, such as when using a logarithmic, for instance on a measuring cup, can vary in scale due to the container's non- cylindrical shape. Graduations along a curve Circular graduations of a scale occur on a circular arc or limb of an instrument. In some cases, non-ci ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Johannes Hevelius Und Elisabetha Hevelius
Johannes is a Medieval Latin form of the personal name that usually appears as "John" in English language contexts. It is a variant of the Greek and Classical Latin variants (Ιωάννης, ''Ioannes''), itself derived from the Hebrew name '' Yehochanan'', meaning "Yahweh is gracious". The name became popular in Northern Europe, especially in Germany because of Christianity. Common German variants for Johannes are ''Johann'', ''Hannes'', '' Hans'' (diminutized to ''Hänschen'' or ''Hänsel'', as known from "''Hansel and Gretel''", a fairy tale by the Grimm brothers), '' Jens'' (from Danish) and ''Jan'' (from Dutch, and found in many countries). In the Netherlands, Johannes was without interruption the most common masculine birth name until 1989. The English equivalent for Johannes is John. In other languages *Joan, Jan, Gjon, Gjin and Gjovalin in Albanian *'' Yoe'' or '' Yohe'', uncommon American form''Dictionary of American Family Names'', Oxford University Press, 2013. *Yaḥy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telescope
A telescope is a device used to observe distant objects by their emission, absorption, or reflection of electromagnetic radiation. Originally meaning only an optical instrument using lenses, curved mirrors, or a combination of both to observe distant objects, the word ''telescope'' now refers to a wide range of instruments capable of detecting different regions of the electromagnetic spectrum, and in some cases other types of detectors. The first known practical telescopes were refracting telescopes with glass lenses and were invented in the Netherlands at the beginning of the 17th century. They were used for both terrestrial applications and astronomy. The reflecting telescope, which uses mirrors to collect and focus light, was invented within a few decades of the first refracting telescope. In the 20th century, many new types of telescopes were invented, including radio telescopes in the 1930s and infrared telescopes in the 1960s. Etymology The word ''telescope'' was ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alidade
An alidade () (archaic forms include alhidade, alhidad, alidad) or a turning board is a device that allows one to sight a distant object and use the line of sight to perform a task. This task can be, for example, to triangulate a scale map on site using a plane table drawing of intersecting lines in the direction of the object from two or more points or to measure the angle and horizontal distance to the object from some reference point's polar measurement. Angles measured can be horizontal, vertical or in any chosen plane. The alidade sighting ruler was originally a part of many types of scientific and astronomical instrument. At one time, some alidades, particularly using circular graduations as on astrolabes, were also called ''diopters''. With modern technology, the name is applied to complete instruments such as the ' plane table alidade'. Origins The word in Arabic ( , "the ruler"), signifies the same device. In Greek and Latin, it is respectively called , "''dioptra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sextant
A sextant is a doubly reflecting navigation instrument that measures the angular distance between two visible objects. The primary use of a sextant is to measure the angle between an astronomical object and the horizon for the purposes of celestial navigation. The estimation of this angle, the altitude, is known as ''sighting'' or ''shooting'' the object, or ''taking a sight''. The angle, and the time when it was measured, can be used to calculate a position line on a nautical or aeronautical chart—for example, sighting the Sun at noon or Polaris at night (in the Northern Hemisphere) to estimate latitude (with sight reduction). Sighting the height of a landmark can give a measure of ''distance off'' and, held horizontally, a sextant can measure angles between objects for a position on a chart. A sextant can also be used to measure the lunar distance between the moon and another celestial object (such as a star or planet) in order to determine Greenwich Mean Time and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tycho Instrument Sextant 16
Tycho is a masculine given name, a latinization of Greek Τύχων, from the name of Tyche ( grc-gre, Τύχη, link=no), the Greek goddess of fortune or luck. The Russian form of the name is ''Tikhon'' (Тихон). People Given name * Tycho Brahe (1546–1601), Danish nobleman and astronomer * Saint Tikhon of Zadonsk (1724–1783), Russian bishop * Tycho van Meer (born 1974), Dutch field hockey striker Surname * Tommy Tycho (1928–2013), Hungarian-Australian pianist, conductor, composer Pseudonym * Tycho (musician) (born 1977) (Scott Hansen), American ambient music artist and producer, also known as ISO50 Astronomy * Tycho (lunar crater) * Tycho Brahe (Martian crater) * The Tycho-1 Catalogue or Tycho-2 Catalogue of stars * SN 1572, a supernova remnant, often called Tycho's supernova * Tycho G, the companion star of SN 1572 * 1677 Tycho Brahe, an asteroid Fiction * Tycho, a desert ranger henchman from the computer game ''Fallout'' * Tycho, a shipboard AI in the computer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
