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NGC 7008
NGC 7008 (PK 93+5.2), also known as the Fetus Nebula, is a planetary nebula with a diameter of approximately 1 light-year located at a distance of 2800 light years in northern Cygnus. It was discovered by William Herschel in 1787, in Slough, England. NGC 7008 (H I-192) is included in the Astronomical League The Astronomical League is an umbrella organization of amateur astronomy societies. Currently their membership consists of over 330 organizations across the United States, along with a number of Members-at-Large, Patrons, and Supporting members. ...'s Herschel 400 observing program.NGC 7008 is that its intricate and delicate structures make it a fascinating target for both amateur and professional astronomers studying the late stages of stellar evolution and the formation of planetary nebulae. References External links * * Cosmic Mystery: NGC 7008 by Dietmar HagerNGC 7008 @ DeepSkyPedia Planetary nebulae Cygnus (constellation) 7008 {{Nebula-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
J2000
In astronomy, an epoch or reference epoch is a moment in time used as a reference point for some time-varying astronomical quantity. It is useful for the celestial coordinates or orbital elements of a celestial body, as they are subject to perturbations and vary with time. These time-varying astronomical quantities might include, for example, the mean longitude or mean anomaly of a body, the node of its orbit relative to a reference plane, the direction of the apogee or aphelion of its orbit, or the size of the major axis of its orbit. The main use of astronomical quantities specified in this way is to calculate other relevant parameters of motion, in order to predict future positions and velocities. The applied tools of the disciplines of celestial mechanics or its subfield orbital mechanics (for predicting orbital paths and positions for bodies in motion under the gravitational effects of other bodies) can be used to generate an ephemeris, a table of values giving ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cygnus (constellation)
Cygnus is a northern constellation on the plane of the Milky Way, deriving its name from the Latinisation of names, Latinized Greek language, Greek word for swan. Cygnus is one of the most recognizable constellations of the northern summer and autumn, and it features a prominent asterism (astronomy), asterism known as the Northern Cross (asterism), Northern Cross (in contrast to the Southern Cross). Cygnus was among the 48 constellations listed by the 2nd century astronomer Ptolemy, and it remains one of the 88 modern constellations. Cygnus contains Deneb (ذنب, translit. ''ḏanab,'' tail)one of the brightest stars in the night sky and the most distant first-magnitude staras its "tail star" and one corner of the Summer Triangle the constellation forming an east pointing Altitude (triangle), altitude of the triangle. It also has some notable X-ray sources and the giant stellar association of Cygnus OB2. One of the stars of this association, NML Cygni, is one of the List of larg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
New General Catalogue
The ''New General Catalogue of Nebulae and Clusters of Stars'' (abbreviated NGC) is an astronomical catalogue of deep-sky objects compiled by John Louis Emil Dreyer in 1888. The NGC contains 7,840 objects, including galaxy, galaxies, star clusters and emission nebulae. Dreyer published two supplements to the NGC in 1895 and 1908, known as the ''Index Catalogues'' (abbreviated IC), describing a further 5,386 astronomical objects. Thousands of these objects are best known by their NGC or IC numbers, which remain in widespread use. The NGC expanded and consolidated the cataloguing work of William Herschel, William and Caroline Herschel, and John Herschel's ''General Catalogue of Nebulae and Clusters of Stars''. Objects south of the Celestial sphere, celestial equator are catalogued somewhat less thoroughly, but many were included based on observation by John Herschel or James Dunlop. The NGC contained multiple errors, but attempts to eliminate them were made by the ''Revised New Ge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Planetary Nebula
A planetary nebula is a type of emission nebula consisting of an expanding, glowing shell of ionized gas ejected from red giant stars late in their lives. The term "planetary nebula" is a misnomer because they are unrelated to planets. The term originates from the planet-like round shape of these nebulae observed by astronomers through early telescopes. The first usage may have occurred during the 1780s with the English astronomer William Herschel who described these nebulae as resembling planets; however, as early as January 1779, the French astronomer Antoine Darquier de Pellepoix described in his observations of the Ring Nebula, "very dim but perfectly outlined; it is as large as Jupiter and resembles a fading planet". Though the modern interpretation is different, the old term is still used. All planetary nebulae form at the end of the life of a star of intermediate mass, about 1-8 solar masses. It is expected that the Sun will form a planetary nebula at the end of i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Light-year
A light-year, alternatively spelled light year (ly or lyr), is a unit of length used to express astronomical distances and is equal to exactly , which is approximately 9.46 trillion km or 5.88 trillion mi. As defined by the International Astronomical Union (IAU), a light-year is the distance that light travels in vacuum in one Julian year (365.25 days). Despite its inclusion of the word "year", the term should not be misinterpreted as a unit of time. The ''light-year'' is most often used when expressing distances to stars and other distances on a galactic scale, especially in non-specialist contexts and popular science publications. The unit most commonly used in professional astronomy is the parsec (symbol: pc, about 3.26 light-years). Definitions As defined by the International Astronomical Union (IAU), the light-year is the product of the Julian year (365.25 days, as opposed to the 365.2425-day Gregorian year or the 365.24219-day Tropical year that both approxim ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Light Years
A light-year, alternatively spelled light year (ly or lyr), is a unit of length used to express astronomical distances and is equal to exactly , which is approximately 9.46 trillion km or 5.88 trillion mi. As defined by the International Astronomical Union (IAU), a light-year is the distance that light travels in vacuum in one Julian year (365.25 days). Despite its inclusion of the word "year", the term should not be misinterpreted as a unit of time. The ''light-year'' is most often used when expressing distances to stars and other distances on a galactic scale, especially in non-specialist contexts and popular science publications. The unit most commonly used in professional astronomy is the parsec (symbol: pc, about 3.26 light-years). Definitions As defined by the International Astronomical Union (IAU), the light-year is the product of the Julian year (365.25 days, as opposed to the 365.2425-day Gregorian year or the 365.24219-day Tropical year that both approximate) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
William Herschel
Frederick William Herschel ( ; ; 15 November 1738 – 25 August 1822) was a German-British astronomer and composer. He frequently collaborated with his younger sister and fellow astronomer Caroline Herschel. Born in the Electorate of Hanover, William Herschel followed his father into the military band of Hanover, before immigrating to Kingdom of Great Britain, Britain in 1757 at the age of nineteen. Herschel constructed his first large telescope in 1774, after which he spent nine years carrying out sky surveys to investigate double stars. Herschel published catalogues of nebulae in 1802 (2,500 objects) and in 1820 (5,000 objects). The resolving power of the Herschel telescopes revealed that many objects called nebulae in the Messier object, Messier catalogue were actually clusters of stars. On 13 March 1781 while making observations he made note of a new object in the constellation of Gemini. This would, after several weeks of verification and consultation with other astrono ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Slough
Slough () is a town in Berkshire, England, in the Thames Valley, west of central London and north-east of Reading, at the intersection of the M4, M40 and M25 motorways. It is part of the historic county of Buckinghamshire. In 2021, the population of the town was 143,184. The wider Borough of Slough had a population of 158,500. Slough's population is one of the most ethnically diverse in the United Kingdom, attracting people from across the country and the world for labour since the 1920s, which has helped shape it into a major trading centre. In 2017, unemployment stood at 1.4%, one-third the UK average of 4.5%. Slough has the highest concentration of UK HQs of global companies outside London. Slough Trading Estate is the largest industrial estate in single private ownership in Europe, with over 17,000 jobs in 400 businesses. Blackberry, McAfee, Burger King, DHL, Telefonica and Lego have head offices in the town. History The name was first recorded in 1195 as ' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Astronomical League
The Astronomical League is an umbrella organization of amateur astronomy societies. Currently their membership consists of over 330 organizations across the United States, along with a number of Members-at-Large, Patrons, and Supporting members. The mission of the Astronomical League is to promote the science of astronomy by (1) fostering astronomical education; (2) providing incentives for astronomical observation and research; and (3) assisting communication among amateur astronomical societies. The Astronomical League provides a number of observing awards to members locating and describing certain specified astronomical objects or events, and produces a periodical publication, ''The Reflector''. History The beginning of the Astronomical League dates back to 1939 when members of eleven amateur astronomical societies met at the American Museum of Natural History in New York City. Similar meetings followed in Pittsburgh, 1940, Washington D.C., 1941, and Detroit, 1946. During th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Herschel 400
The Herschel 400 catalogue is a subset of William Herschel's original ''Catalogue of Nebulae and Clusters of Stars'', selected by Brenda F. Guzman (Branchett), Lydel Guzman, Paul Jones, James Morris, Peggy Taylor and Sara Saey of the Ancient City Astronomy Club in St. Augustine, Florida, United States 1980. They decided to generate the list after reading a letter published in ''Sky & Telescope'' by James Mullaney of Pittsburgh, Pennsylvania, United States. In this letter Mr. Mullaney suggested that William Herschel's original catalogue of 2,500 objects would be an excellent basis for deep sky object selection for amateur astronomers looking for a challenge after completing the Messier Catalogue. The Herschel 400 is a subset of John Herschel's '' General Catalogue of Nebulae and Clusters'' published in 1864 of 5,000 objects, and hence also of the ''New General Catalogue''. The catalogue forms the basis of thAstronomical League's Herschel 400 club In 1997, another subset of 400 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
