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Sextans (constellation)
Sextans is a faint, minor constellation on the celestial equator which was introduced in 1687 by Polish people, Polish astronomer Johannes Hevelius. Its name is Latin for the astronomical sextant, an instrument that Hevelius made frequent use of in his observations. Characteristics Sextans is a medium sized constellation bordering Leo (constellation), Leo to the north, touching on Hydra (constellation), Hydra to the southwest, and Crater (constellation), Crater to the southeast. The recommended three-letter abbreviation for the constellation, as adopted by the International Astronomical Union in 1922, is "Sex". The official constellation boundaries, as set by Belgian astronomer Eugène Joseph Delporte, Eugène Delporte in 1930, are defined by a square. In the equatorial coordinate system, the right ascension coordinates of these borders lie between and , while the declination coordinates are between +6.43° and −11.7°. Since it is close to the ecliptic plane, the Moon and p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sextant (astronomy)
In astronomy, sextants are devices depicting a sixth of a circle, used primarily for measuring the star position, 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 Axial tilt, 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 (astronomy), meridian (north–south) line. Al Khujandi's instrument was larger than previous instruments; it had a radius of about twenty meters.Sevim Tekeli, Tekeli, Sevim (1958), 'Nasiruddin, Takiyudd ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eugène Joseph Delporte
Eugène Joseph Delporte (10 January 1882 – 19 October 1955) was a Belgian astronomer born in Genappe. He discovered a total of sixty-six asteroids. Notable discoveries include 1221 Amor (which lent its name to the Amor asteroids) and the Apollo asteroid 2101 Adonis. He discovered or co-discovered some comets as well, including periodic comet 57P/du Toit-Neujmin-Delporte. He worked in the Observatoire Royal de Belgique (Belgian Royal Observatory), situated in the town of Uccle (after which the asteroid 1276 Ucclia is named). He started there in 1903 after receiving his doctorate that year from the Free University of Brussels. In 1930, he drew the modern boundaries between all of the constellations in the sky, along lines of right ascension and declination In astronomy, declination (abbreviated dec; symbol ''δ'') is one of the two angles that locate a point on the celestial sphere in the equatorial coordinate system, the other being hour angle. The declination ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
A-type Star
A type or type A may refer to: Science * A-type asteroid, a type of relatively uncommon inner-belt asteroids * A type blood, a type in the ABO blood group system * A-type inclusion, a type of cell inclusion * A-type potassium channel, a type of voltage-gated potassium channel * A type proanthocyanidin, a specific type of flavonoids * A-type star, a class of stars * Type A climate, a type in the Köppen climate classification * Type A flu, a type of influenza virus * Type A evaluation of uncertainty, an uncertainty in measurement that can be inferred, for example, from repeated measurement * Type A personality, a personality type in the Type A and Type B personality theory * Hemophilia type A, a type of haemophilia * A-type granite a type of granite rock * Adenosine receptor The adenosine receptors (or P1 receptors) are a class of Purinergic receptor, purinergic G protein-coupled receptors with adenosine as the endogenous ligand (biochemistry), ligand. There are four kno ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apparent Magnitude
Apparent magnitude () is a measure of the Irradiance, brightness of a star, astronomical object or other celestial objects like artificial satellites. Its value depends on its intrinsic luminosity, its distance, and any extinction (astronomy), extinction of the object's light caused by interstellar dust along the sightline, line of sight to the observer. Unless stated otherwise, the word ''magnitude'' in astronomy usually refers to a celestial object's apparent magnitude. The magnitude scale likely dates to before the ancient Ancient Greek astronomy#Astronomy in the Greco-Roman and Late Antique eras, Roman astronomer Ptolemy, Claudius Ptolemy, whose Star catalogue, star catalog popularized the system by listing stars from First-magnitude star, 1st magnitude (brightest) to 6th magnitude (dimmest). The modern scale was mathematically defined to closely match this historical system by Norman Robert Pogson, Norman Pogson in 1856. The scale is reverse logarithmic scale, logarithmic: ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sky & Telescope
''Sky & Telescope'' (''S&T'') is a monthly magazine covering all aspects of amateur and professional astronomy, including what to see in the sky tonight and new findings in astronomy. Other topics covered include: *observing guides for planets, galaxies, star clusters, and other objects visible in the night sky *reviews of telescopes and other astronomical equipment, books, and software *events in the amateur astronomy community * amateur telescope making * astrophotography The articles are intended for the informed lay reader and include detailed discussions of current discoveries, frequently by participating scientists. The magazine is illustrated in full color, with both amateur and professional photography of celestial sights, as well as tables and charts of upcoming celestial events. History ''Sky & Telescope'' was founded by Charles A. Federer and his wife Helen Spence Federer. The duo had formed the Sky Publishing Corporation in late 1939 to manage a magazine called '' T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Greek Letter
The Greek alphabet has been used to write the Greek language since the late 9th or early 8th century BC. It was derived from the earlier Phoenician alphabet, and is the earliest known alphabetic script to systematically write vowels as well as consonants. In Archaic Greece, Archaic and early Classical Greece, Classical times, the Greek alphabet existed in Archaic Greek alphabets, many local variants, but, by the end of the 4th century BC, the Ionia, Ionic-based Euclidean alphabet, with 24 letters, ordered from alpha to omega, had become standard throughout the Greek-speaking world and is the version that is still used for Greek writing today. The letter case, uppercase and lowercase forms of the 24 letters are: : , , , , , , , , , , , , , , , , , , , , , , , The Greek alphabet is the ancestor of several scripts, such as the Latin script, Latin, Gothic alphabet, Gothic, Coptic script, Coptic, and Cyrillic scripts. Throughout antiquity, Greek had only a single uppercas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Benjamin Apthorp Gould
Benjamin Apthorp Gould (September 27, 1824 – November 26, 1896) was a pioneering American astronomer. He is noted for creating the ''Astronomical Journal'', discovering the Gould Belt, and for founding of the Argentine National Observatory and the Argentine National Weather Service. Biography He was born in Boston, Massachusetts, the son of Lucretia Dana (Goddard) and Benjamin Apthorp Gould, the principal of Boston Latin School, which the younger Gould attended. The poet Hannah Flagg Gould was his aunt. After going on to Harvard College and graduating in 1844, he studied mathematics and astronomy under C. F. Gauss at Göttingen, Germany, during which time he published approximately 20 papers on the observation and motion of comets and asteroids. Following completion of his Ph.D. (he was the first American to receive this degree in astronomy) he toured European observatories asking for advice on what could be done to further astronomy as a professional science in the U.S.A. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bayer Designation
A Bayer designation is a stellar designation in which a specific star is identified by a Greek alphabet, Greek or Latin letter followed by the genitive case, genitive form of its parent constellation's Latin name. The original list of Bayer designations contained 1564 stars. The brighter stars were assigned their first systematic names by the German astronomer Johann Bayer in 1603, in his star atlas ''Uranometria''. Bayer catalogued only a few stars too far south to be seen from Germany, but later astronomers (including Nicolas-Louis de Lacaille and Benjamin Apthorp Gould) supplemented Bayer's catalog with entries for southern constellations. Scheme Bayer assigned a lowercase Greek alphabet, Greek letter (alpha (α), beta (β), gamma (γ), etc.) or a Latin letter (A, b, c, etc.) to each star he catalogued, combined with the Latin name of the star's parent constellation in genitive case, genitive (possessive) form. The constellation name is frequently abbreviated to a standard three ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Francis Baily
Francis Baily (28 April 177430 August 1844) was an English astronomer. He is most famous for his observations of " Baily's beads" during a total eclipse of the Sun. Baily was also a major figure in the early history of the Royal Astronomical Society, as one of the founders and as the president four times. Life Baily was born at Newbury in Berkshire in 1774 to Richard Baily. After a tour in the unsettled parts of North America in 1796–1797, his journal of which was edited by Augustus De Morgan in 1856, Baily entered the London Stock Exchange in 1799. The successive publication of ''Tables for the Purchasing and Renewing of Leases'' (1802), of ''The Doctrine of Interest and Annuities'' (1808), and ''The Doctrine of Life-Annuities and Assurances'' (1810), earned him a high reputation as a writer on life-contingencies; he amassed a fortune through diligence and integrity and retired from business in 1825, to devote himself wholly to astronomy. This also cites * J. Herschel's ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Virginia
Virginia, officially the Commonwealth of Virginia, is a U.S. state, state in the Southeastern United States, Southeastern and Mid-Atlantic (United States), Mid-Atlantic regions of the United States between the East Coast of the United States, Atlantic Coast and the Appalachian Mountains. The state's List of capitals in the United States, capital is Richmond, Virginia, Richmond and its most populous city is Virginia Beach, Virginia, Virginia Beach. Its most populous subdivision is Fairfax County, Virginia, Fairfax County, part of Northern Virginia, where slightly over a third of Virginia's population of more than 8.8million live. Eastern Virginia is part of the Atlantic Plain, and the Middle Peninsula forms the mouth of the Chesapeake Bay. Central Virginia lies predominantly in the Piedmont (United States), Piedmont, the foothill region of the Blue Ridge Mountains, which cross the western and southwestern parts of the state. The fertile Shenandoah Valley fosters the state's mo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
John Flamsteed
John Flamsteed (19 August 1646 – 31 December 1719) was an English astronomer and the first Astronomer Royal. His main achievements were the preparation of a 3,000-star catalogue, ''Catalogus Britannicus'', and a star atlas called '' Atlas Coelestis'', both published posthumously. He also made the first recorded observations of Uranus, although he mistakenly catalogued it as a star, and he laid the foundation stone for the Royal Greenwich Observatory. Life Flamsteed was born in Denby, Derbyshire, England, the only son of Stephen Flamsteed and his first wife, Mary Spadman. He was educated at the free school of Derby and at Derby School, in St Peter's Churchyard, Derby, near where his father carried on a malting business. At that time, most masters of the school were Puritans. Flamsteed had a solid knowledge of Latin, essential for reading the scientific literature of the day, and a love of history, leaving the school in May 1662.Birks, John L. (1999) ''John Flamsteed, t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
