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Robert T. A. Innes
Robert Thorburn Ayton Innes FRSE FRAS (10 November 1861 – 13 March 1933) was a British-born South African astronomer best known for discovering Proxima Centauri in 1915, and numerous binary stars. He was also the first astronomer to have seen the Great January Comet of 1910, on 12 January. He was the founding director of a meteorological observatory in Johannesburg, which was later converted to an astronomical observatory and renamed to Union Observatory. He was the first Union Astronomer. Innes House, designed by Herbert Baker, built as his residence at the observatory, today houses the South African Institute of Electrical Engineers. Biography He was born on 10 November 1861 in Edinburgh to John and Elizabeth (née Ayton) Innes. He had 11 younger siblings. A self-taught astronomer, he went to Australia at an early age and made his living as a wine merchant in Sydney, where, using a home made 12-inch reflecting telescope, he discovered several double stars new to astro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Robert Thorburn Ayton Innes00
The name Robert is an ancient Germanic given name, from Proto-Germanic "fame" and "bright" (''Hrōþiberhtaz''). Compare Old Dutch ''Robrecht'' and Old High German ''Hrodebert'' (a compound of ''Hrōþ, Hruod'' () "fame, glory, honour, praise, renown, godlike" and ''berht'' "bright, light, shining"). It is the second most frequently used given name of ancient Germanic origin.Reaney & Wilson, 1997. ''Dictionary of English Surnames''. Oxford University Press. It is also in use Robert (surname), as a surname. Another commonly used form of the name is Rupert (name), Rupert. After becoming widely used in Continental Europe, the name entered England in its Old French form ''Robert'', where an Old English cognate form (''Hrēodbēorht'', ''Hrodberht'', ''Hrēodbēorð'', ''Hrœdbœrð'', ''Hrœdberð'', ''Hrōðberχtŕ'') had existed before the Norman Conquest. The feminine version is Roberta (given name), Roberta. The Italian, Portuguese, and Spanish form is Roberto (given name), ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Double Stars
In observational astronomy, a double star or visual double is a pair of stars that appear close to each other as viewed from Earth, especially with the aid of optical telescopes. This occurs because the pair either forms a binary star (i.e. a binary system of stars in mutual orbit, gravitationally bound to each other) or is an ''optical double'', a chance line-of-sight alignment of two stars at different distances from the observer. Binary stars are important to stellar astronomers as knowledge of their motions allows direct calculation of stellar mass and other stellar parameters. The only (possible) case of "binary star" whose two components are separately visible to the naked eye is the case of Mizar and Alcor (though actually a multiple-star system), but it is not known for certain whether Mizar and Alcor are gravitationally bound. Since the beginning of the 1780s, both professional and amateur double star observers have telescopically measured the distances and angles bet ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stellar Parallax
Stellar parallax is the apparent shift of position (''parallax'') of any nearby star (or other object) against the background of distant stars. By extension, it is a method for determining the distance to the star through trigonometry, the stellar parallax method. Created by the different orbital positions of Earth, the extremely small observed shift is largest at time intervals of about six months, when Earth arrives at opposite sides of the Sun in its orbit, giving a baseline (the shortest side of the triangle made by a star to be observed and two positions of Earth) distance of about two astronomical units between observations. The parallax itself is considered to be half of this maximum, about equivalent to the observational shift that would occur due to the different positions of Earth and the Sun, a baseline of one astronomical unit (AU). Stellar parallax is so difficult to detect that its existence was the subject of much debate in astronomy for hundreds of years. Thomas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Harold Lee Alden
Harold Lee Alden (January 10, 1890 – February 3, 1964) was an American astronomer. Early years and education Alden was born in Chicago, Illinois. He received his Bachelor of Arts from Wheaton College (Illinois) in 1912 and his master's from the University of Chicago in 1913. From 1912 to 1913 he was an assistant in the photographic photometry program at the Yerkes Observatory. He received his Ph.D. in 1917 from the University of Virginia. Professional life He worked for twenty years at the Yale University, Yale Observatory in South Africa before returning to the University of Virginia. He is noted mainly for measuring stellar parallax, the proper motion of stars and long period variable stars. The crater Alden (crater), Alden on the far side (Moon), far side of the Moon is named in his honor. He returned to the University of Virginia in 1945 to become a Professor of Astronomy, chairman of the Astronomy Department and Director of the Leander McCormick Observatory. In 1951 he w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Astrograph
An astrograph (or astrographic camera) is a telescope designed for the sole purpose of astrophotography. Astrographs are mostly used in wide-field astronomical surveys of the sky and for detection of objects such as asteroids, meteors, and comets. Improvements in photography in the middle 19th century led to designs dedicated to astrophotography, and they were also popular in the 20th century. As in other photography, chemicals were used that respond to light, recorded on a glass photographic plate or sometimes on photographic film. Many observatories of this period used an astrograph, beside instruments like the transit telescope, great refractors, and chronometers, or instruments for observing the Sun. Astrographs were often used to make surveys of the night sky, and one of the famous projects was Carte du Ciel. Discoveries using an astrograph include then-planet Pluto. Rather than looking through the telescope, it was discovered by using a blink comparator with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alpha Centauri
Alpha Centauri (, α Cen, or Alpha Cen) is a star system in the southern constellation of Centaurus (constellation), Centaurus. It consists of three stars: Rigil Kentaurus (), Toliman (), and Proxima Centauri (). Proxima Centauri is the List of nearest stars, closest star to the Sun at 4.2465 light-years (ly) which is 1.3020 parsecs (pc). Rigil Kentaurus and Toliman are Sun-like stars (G-type main-sequence star, class G and K-type main-sequence star, K, respectively) that together form the binary star system . To the naked eye, these two main components appear to be a single star with an apparent magnitude of −0.27. It is the brightest star in the constellation and the List of brightest stars, third-brightest in the night sky, outshone by only Sirius and Canopus. Rigil Kentaurus has 1.1 times the Solar mass, mass () and 1.5 times the Solar luminosity, luminosity of the Sun (), while Toliman is smaller and cooler, at and less than . The pair ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Proper Motion
Proper motion is the astrometric measure of changes in the apparent places of stars or other celestial objects as they move relative to the center of mass of the Solar System. It is measured relative to the distant stars or a stable reference such as the International Celestial Reference Frame (ICRF). Patterns in proper motion reveal larger structures like stellar streams, the general rotation of the Milky Way disk, and the random motions of stars in the Galactic halo. The components for proper motion in the equatorial coordinate system (of a given epoch, often J2000.0) are given in the direction of right ascension (''μ''α) and of declination (''μ''δ). Their combined value is computed as the ''total proper motion'' (''μ''). It has dimensions of angle per time, typically arcseconds per year or milliarcseconds per year. Knowledge of the proper motion, distance, and radial velocity allows calculations of an object's motion from the Solar System's frame of reference an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Visual Binary
A visual binary is a gravitationally bound binary star system that can be resolved into two stars. These stars are estimated, via Kepler's third law, to have periods ranging from a few years to thousands of years. A visual binary consists of two stars, usually of a different brightness. Because of this, the brighter star is called the primary and the fainter one is called the companion. If the primary is too bright, relative to the companion, this can cause a glare making it difficult to resolve the two components. However, it is possible to resolve the system if observations of the brighter star show it to wobble about a centre of mass. In general, a visual binary can be resolved into two stars with a telescope if their centres are separated by a value greater than or equal to one arcsecond, but with modern professional telescopes, interferometry, or space-based equipment, stars can be resolved at closer distances. For a visual binary system, measurements taken need to specify, in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Johannesburg
Johannesburg ( , , ; Zulu language, Zulu and Xhosa language, Xhosa: eGoli ) (colloquially known as Jozi, Joburg, Jo'burg or "The City of Gold") is the most populous city in South Africa. With 5,538,596 people in the City of Johannesburg alone and over 14.8 million in the urban agglomeration, it is classified as a Megacity#List of megacities, megacity and List of urban areas by population, one of the 100 largest urban areas in the world. Johannesburg is the provinces of South Africa, provincial capital of Gauteng, the wealthiest province in South Africa, and seat of the country's highest court, the Constitutional Court of South Africa, Constitutional Court. The city is located within the mineral-rich Witwatersrand hills, the epicentre of the international mineral and gold trade. The richest city in Africa by GDP and private wealth, Johannesburg functions as the economic capital of South Africa and is home to the continent's largest stock exchange, the Johannesburg Stock Exchang ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kapteyn's Star
Kapteyn's Star is a class M1 red subdwarf about 12.83 light-years from Earth in the southern constellation Pictor; it is the closest halo star to the Solar System. With an apparent magnitude of nearly 9, it is visible through binoculars or a telescope. Its diameter is 30% of the Sun's, but its luminosity just 1.2% that of the Sun. It may have once been part of the globular cluster Omega Centauri, itself the likely core of a dwarf galaxy swallowed up by the Milky Way in the distant past. The discovery of two planets—Kapteyn b and Kapteyn c—was announced in 2014, but had a mixed history of rejections and confirmations, until a 2021 study refuted both planets. The "planets" are in fact artifacts of the star's rotation and activity. History of observations Attention was first drawn to what is now known as Kapteyn's Star by the Dutch astronomer Jacobus Kapteyn in 1898. Under the name CPD-44 612 it was included in the ''Cape photographic Durchmusterung for the equino ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
David Gill (astronomer)
Sir David Gill (12 June 1843 – 24 January 1914) was a Scottish astronomer who is known for measuring astronomical distances, for astrophotography and geodesy. He spent much of his career in South Africa. Life and work David Gill was born at 48 Skene Terrace in Aberdeen the son of David Gill, watchmaker and his wife Margaret Mitchell. He was educated first at Bellevue Academy in Aberdeen then at Dollar Academy. He spent two years at Aberdeen University, where he was taught by James Clerk Maxwell, and then joined his father's clock-making business. His most important influence at university was probably from Prof David Thomson. In 1863 they jointly repaired the university clock and both set up a new mechanical telescope at the Cromwell Tower Observatory. This was his introduction to astronomy. It would seem that Gill's interests lay elsewhere since after a few years he sold the business, and then spent time equipping Lord Lindsay's private observatory at Dun Echt, Aberd ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Royal Observatory, Cape Of Good Hope
The Royal Observatory, Cape of Good Hope, is a former scientific institution in South Africa. Founded by the British Board of Longitude in 1820, its main building is now the headquarters building of the South African Astronomical Observatory. The institution was located on a small hill south-east from the centre of Cape Town. During the succeeding century a suburb of the city formed in the area; the suburb was named Observatory after the pre-existing Royal Observatory. It was declared a National Heritage Site in December 2018 and has also been the subject of an ICOMOS/IAU Case Study as a World Heritage Site. History The proposal for a Southern observatory in all likelihood originated among the same group of people who founded the Royal Astronomical Society in the United Kingdom. The official establishment of the Royal Observatory, Cape of Good Hope occurred on 20 October 1820 through an Order in Council of King George IV of the United Kingdom. It remained a separate entit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
