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McNeil's Nebula
McNeil's Nebula is a variable nebula discovered January 23, 2004 by Jay McNeil of Paducah, Kentucky. It is illuminated by the star V1647 Ori. Discovery McNeil's Nebula is a cometary-type reflection nebula, illuminated by the reddish star V1647 Ori (also catalogued as IRAS 05436-0007) at its southern tip. The nebula did not appear in images taken before September 2003; it was discovered in 2004 by amateur astronomer Jay McNeil using a 3-inch telescope. University of Hawaii researcher Bo Reipurth's preliminary studies have determined that McNeil's Nebula appeared when V1647 Ori, a pre-main sequence star, experienced an outburst called a FU Orionis or EX Lupii type event. Most stars are believed to undergo such events, though they are rarely observed. Earlier images The nebula has been identified on images taken by Evered Kreimer in October 1966, but not in various other images taken between 1951 and 1991. The nebula appears therefore to be very variable in luminosity, and is a r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
J2000
In astronomy, an epoch or reference epoch is a instant, 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 Astronomical object, celestial body, as they are subject to Perturbation (astronomy), 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 Perihelion and aphelion, 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 bodi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Variable Nebula
Variable nebulae are reflection nebulae that change in brightness because of changes in their star. See also *McNeil's Nebula *NGC 1555 (Hind's Variable Nebula) *NGC 2261 (Hubble's Variable Nebula) *NGC 6729 NGC 6729 (also known as Caldwell 68) is a reflection/ emission nebula of the Corona Australis Molecular Cloud in the constellation Corona Australis. It was discovered by Johann Friedrich Julius Schmidt in 1861. This fan-shaped nebula opens from ... (R Coronae Australis Nebula) References External links Astrobiscuit: Seeing The Speed Of Lightfun and educational video about variable nebula and the amateur community observing them {{nebula * Nebulae ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paducah, Kentucky
Paducah ( ) is a home rule-class city in and the county seat of McCracken County, Kentucky. The largest city in the Jackson Purchase region, it is located at the confluence of the Tennessee and the Ohio rivers, halfway between St. Louis, Missouri, to the northwest and Nashville, Tennessee, to the southeast. As of the 2020 census, the population was 27,137, up from 25,024 during the 2010 U.S. Census. Twenty blocks of the city's downtown have been designated as a historic district and listed on the National Register of Historic Places. Paducah is the hub of its micropolitan area, which includes McCracken, Ballard and Livingston counties in Kentucky and Massac County in Illinois. History Early history Paducah was first settled as "Pekin" around 1821 by European Americans James and William Pore.Rennick, Robert. ''Kentucky Place Names''p. 224 University Press of Kentucky (Lexington), 1987. Accessed August 1, 2013. The town was laid out by explorer and surveyor William Clark in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kentucky
Kentucky ( , ), officially the Commonwealth of Kentucky, is a state in the Southeastern region of the United States and one of the states of the Upper South. It borders Illinois, Indiana, and Ohio to the north; West Virginia and Virginia to the east; Tennessee to the south; and Missouri to the west. Its northern border is defined by the Ohio River. Its capital is Frankfort, and its two largest cities are Louisville and Lexington. Its population was approximately 4.5 million in 2020. Kentucky was admitted into the Union as the 15th state on June 1, 1792, splitting from Virginia in the process. It is known as the "Bluegrass State", a nickname based on Kentucky bluegrass, a species of green grass found in many of its pastures, which has supported the thoroughbred horse industry in the center of the state. Historically, it was known for excellent farming conditions for this reason and the development of large tobacco plantations akin to those in Virginia and North Carolina i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
BBC News
BBC News is an operational business division of the British Broadcasting Corporation (BBC) responsible for the gathering and broadcasting of news and current affairs in the UK and around the world. The department is the world's largest broadcast news organisation and generates about 120 hours of radio and television output each day, as well as online news coverage. The service maintains 50 foreign news bureaus with more than 250 correspondents around the world. Deborah Turness has been the CEO of news and current affairs since September 2022. In 2019, it was reported in an Ofcom report that the BBC spent £136m on news during the period April 2018 to March 2019. BBC News' domestic, global and online news divisions are housed within the largest live newsroom in Europe, in Broadcasting House in central London. Parliamentary coverage is produced and broadcast from studios in London. Through BBC English Regions, the BBC also has regional centres across England and national news c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sky & Telescope
''Sky & Telescope'' (''S&T'') is a monthly American magazine covering all aspects of amateur astronomy, including the following: *current events in astronomy and space exploration; *events in the amateur astronomy community; *reviews of astronomical equipment, books, and computer software; *amateur telescope making; and *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 and began publication at Harvard College Observatory in November 1941, as a result of the merger of the separate magazines, '' The Sky'' and '' The Telescope''. In 2005, Sky Publishing Corporation was acquired by New Track Media, a portfo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dobsonian Telescope
A Dobsonian telescope is an altazimuth-mounted Newtonian telescope design popularized by John Dobson in 1965 and credited with vastly increasing the size of telescopes available to amateur astronomers. Dobson's telescopes featured a simplified mechanical design that was easy to manufacture from readily available components to create a large, portable, low-cost telescope. The design is optimized for observing faint, deep-sky objects such as nebulae and galaxies. This type of observation requires a large objective diameter (i.e. light-gathering power) of relatively short focal length and portability for travel to less light-polluted locations. Dobsonians are intended to be what is commonly called a "light bucket" operating at low magnification, and therefore the design omits features found in other amateur telescopes such as equatorial tracking. Dobsonians are popular in the amateur telescope making community, where the design was pioneered and continues to evolve. A number o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reflection Nebulae
Reflection or reflexion may refer to: Science and technology * Reflection (physics), a common wave phenomenon ** Specular reflection, reflection from a smooth surface *** Mirror image, a reflection in a mirror or in water ** Signal reflection, in signal transmission * Elastic scattering, a process in nuclear and particle physics * Reflection nebula, a nebula that is extended and has no boundaries * Reflection seismology or seismic reflection, a method of exploration geophysics Mathematics * Reflection principle, in set theory * Point reflection, a reflection across a point * Reflection (mathematics), a transformation of a space * Reflection formula, a relation in a function * Reflective subcategory, in category theory Computing * Reflection (computer graphics), simulation of reflective surfaces * Reflection (computer programming), a program that accesses or modifies its own code * Reflection, terminal emulation software by Attachmate Arts and entertainment Film and televisi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orion Molecular Cloud Complex
The Orion molecular cloud complex (or, simply, the Orion complex) is a star-forming region with stellar ages ranging up to 12 Myr. Two giant molecular clouds are a part of it, Orion A and Orion B. The stars currently forming within the complex are located within these clouds. A number of other somewhat older stars no longer associated with the molecular gas are also part of the complex, most notably the Orion's Belt (Orion OB1b), as well as the dispersed population north of it ( Orion OB1a). Near the head of Orion there is also a population of young stars that is centered on Meissa. The complex is between 1 000 and 1 400 light-years away, and hundreds of light-years across. The Orion complex is one of the most active regions of nearby stellar formation visible in the night sky, and is home to both protoplanetary discs and very young stars. Much of it is bright in infrared wavelengths due to the heat-intensive processes involved in stellar formation, though the complex c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protostars
A protostar is a very young star that is still gathering mass from its parent molecular cloud. The protostellar phase is the earliest one in the process of stellar evolution. For a low-mass star (i.e. that of the Sun or lower), it lasts about 500,000 years. The phase begins when a molecular cloud fragment first collapses under the force of self-gravity and an opaque, pressure supported core forms inside the collapsing fragment. It ends when the infalling gas is depleted, leaving a pre-main-sequence star, which contracts to later become a main-sequence star at the onset of hydrogen fusion producing helium. History The modern picture of protostars, summarized above, was first suggested by Chushiro Hayashi in 1966. In the first models, the size of protostars was greatly overestimated. Subsequent numerical calculations clarified the issue, and showed that protostars are only modestly larger than main-sequence stars of the same mass. This basic theoretical result has been confirmed by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
