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790 Pretoria
790 Pretoria is a minor planet orbiting the Sun that was discovered by English astronomer Harry Edwin Wood on January 16, 1912. It is a member of the Cybele group located beyond the core of the main belt (see Minor planet groups) and named after Pretoria, the capital city of South Africa. 10 μ radiometric data collected from Kitt Peak in 1975 gave a diameter estimate of 175 km. In the present day it is estimated to be in diameter. Photometric measurements of the asteroid made in 2005 at the Palmer Divide Observatory showed a light curve with a period of 10.370 ± 0.002 hours and a brightness variation of 0.08 ± 0.03 in magnitude. 790 Pretoria has been observed to occult 15 stars between 1998 and 2023. References External links Lightcurve plot of 790 Pretoria Palmer Divide Observatory, B. D. Warner (2009) Asteroid Lightcurve Database (LCDB) query form) Dictionary of Minor Planet Names Google books – Observatoire de Genève, Raoul Behrend – Minor Planet Cen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Johannesburg Observatory
Union Observatory also known as Johannesburg Observatory ( 078) is a defunct astronomical observatory in Johannesburg, South Africa that was operated between 1903 and 1971. It is located on Observatory Ridge, the city's highest point at 1,808 metres altitude in the suburb Observatory. The observatory and its former annex, the , are known for the discovery of 6,000 double stars and for Proxima Centauri, made by astronomer Robert Innes. At the observatory, 578 identifications of minor planet were made, a record number at the time. The Minor Planet Center credits the observatory as the site where 147 minor planets were discovered by astronomers Harry Wood, Cyril Jackson, Hendrik van Gent, Ernest Johnson, Ejnar Hertzsprung, Jacobus Bruwer and Joseph Churms ''(see )''. History The origins of the observatory began when Theodore Reunert of the South African Association for the Advancement of Science petitioned Alfred Milner Governor of the Transvaal Colony on 29 October 1902 for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Micrometre
The micrometre ( international spelling as used by the International Bureau of Weights and Measures; SI symbol: μm) or micrometer (American spelling), also commonly known as a micron, is a unit of length in the International System of Units (SI) equalling (SI standard prefix "micro-" = ); that is, one millionth of a metre (or one thousandth of a millimetre, , or about ). The nearest smaller common SI unit is the nanometre, equivalent to one thousandth of a micrometre, one millionth of a millimetre or one billionth of a metre (). The micrometre is a common unit of measurement for wavelengths of infrared radiation as well as sizes of biological cells and bacteria, and for grading wool by the diameter of the fibres. The width of a single human hair ranges from approximately 20 to . The longest human chromosome, chromosome 1, is approximately in length. Examples Between 1 μm and 10 μm: * 1–10 μm – length of a typical bacterium * 3–8 μm – width of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Named Minor Planets
Named may refer to something that has been given a name. Named may also refer to: * named (computing), a widely used DNS server * Naming (parliamentary procedure) * The Named (band), an American industrial metal group In literature: * ''The Named'', a fantasy novel by Marianne Curley * The Named, a fictional race of prehistoric big cats, depicted in ''The Books of the Named'' series by Clare Bell See also * Name (other) * Names (other) Names are words or terms used for identification. Names may also refer to: * ''Names'' (EP), by Johnny Foreigner * ''Names'' (journal), an academic journal of onomastics * The Names (band), a Belgian post-punk band * ''The Names'' (novel), by ... * Naming (other) {{disambiguation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Discoveries By Harry Edwin Wood
Discoveries may refer to: Music * ''Discoveries'' (Cannonball Adderley album), 1955 * ''Discoveries'' (Josh Nelson album), 2011 * ''Discoveries'' (Northlane album), 2011 Other uses * ''Discoveries'' (film), a 1939 British film * Discoveries (horse), a racehorse * ''Discoveries'' (Robertson Davies), a 2002 book by Robertson Davies * ''Discoveries'' (TV series), a Canadian youth science television series which aired on CBC Television in 1957 * ''Abrams Discoveries'', a series of illustrated non-fiction books published by Harry N. Abrams * ''Discoveries'', a work by William Butler Yeats, written in 1907 * ''Discoveries'', a magazine published by Cedars-Sinai Medical Center See also * Age of Discoveries * Discovery (other) Discovery may refer to: * Discovery (observation), observing or finding something unknown * Discovery (fiction), a character's learning something unknown * Discovery (law), a process in courts of law relating to evidence Discovery, The Discov ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cybele Asteroids
The Cybele asteroids (also known as the "Cybeles") are a dynamical group of asteroids, named after the asteroid 65 Cybele. Considered by some as the last outpost of an extended asteroid belt, the group consists of just over 2000 members and a few collisional families. The Cybeles are in a 7:4 orbital resonance with Jupiter. Their orbit is defined by an osculating semi-major axis of 3.28 to 3.70 AU, with an eccentricity of less than 0.3, and an inclination less than 25°. The dynamical Cybele group is located adjacent to the outermost asteroid belt, beyond the Hecuba gap – the 2:1 resonant zone with Jupiter, where the Griqua asteroids are located – and inside the orbital region of the Hilda asteroids (3:2 resonance), which are themselves followed by the Jupiter trojans (1:1 resonance) further out. Description Three known asteroid families exist within the Cybele group: the Sylvia family (603), the Huberta family and the Ulla family (903). A potential fourth fami ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brian D
Brian (sometimes spelled Bryan in English) is a male given name of Irish and Breton origin, as well as a surname of Occitan origin. It is common in the English-speaking world. It is possible that the name is derived from an Old Celtic word meaning "high" or "noble". For example, the element ''bre'' means "hill"; which could be transferred to mean "eminence" or "exalted one". The name is quite popular in Ireland, on account of Brian Boru, a 10th-century High King of Ireland. The name was also quite popular in East Anglia during the Middle Ages. This is because the name was introduced to England by Bretons following the Norman Conquest. Bretons also settled in Ireland along with the Normans in the 12th century, and 'their' name was mingled with the 'Irish' version. Also, in the north-west of England, the 'Irish' name was introduced by Scandinavian settlers from Ireland. Within the Gaelic speaking areas of Scotland, the name was at first only used by professional families of Irish o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Occultation
An occultation is an event that occurs when one object is hidden from the observer by another object that passes between them. The term is often used in astronomy, but can also refer to any situation in which an object in the foreground blocks from view (occults) an object in the background. In this general sense, occultation applies to the visual scene observed from low-flying aircraft (or computer-generated imagery) when foreground objects obscure distant objects dynamically, as the scene changes over time. If the closer body does not entirely conceal the farther one, the event is called a ''transit''. Both transit and occultation may be referred to generally as ''occlusion''; and if a shadow is cast onto the observer, it is called an eclipse. The symbol for an occultation, and especially a solar eclipse, is file:Occultation symbol.svg (U+1F775 🝵). Occultations by the Moon The term occultation is most frequently used to describe lunar occultations, those relativ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Light Curve
In astronomy, a light curve is a graph of light intensity of a celestial object or region as a function of time, typically with the magnitude of light received on the y axis and with time on the x axis. The light is usually in a particular frequency interval or band. Light curves can be periodic, as in the case of eclipsing binaries, Cepheid variables, other periodic variables, and transiting extrasolar planets, or aperiodic, like the light curve of a nova, a cataclysmic variable star, a supernova or a microlensing event or binary as observed during occultation events. The study of the light curve, together with other observations, can yield considerable information about the physical process that produces it or constrain the physical theories about it. Variable stars Graphs of the apparent magnitude of a variable star over time are commonly used to visualise and analyse their behaviour. Although the categorisation of variable star types is increasingly done from their s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Palmer Divide
Named after Colorado Springs founder William Jackson Palmer, the Palmer Divide is a caprock escarpment style ridge in central Colorado that separates the Arkansas River basin from the South Platte basin. It extends from the Front Range of the Rockies in central Colorado eastward approximately 80 miles toward the town of Limon. The western end of the Palmer Divide is popularly considered to be at Palmer Lake, located south of Denver and north of Colorado Springs. However, the divide between the two river basins actually extends west and then north to a junction with the Continental Divide at McNamee Peak. For much of its length, it travels very roughly along the northern border of El Paso County. Thus, it forms a natural separator between the Denver and Colorado Springs metropolitan areas. The elevation along the divide varies between about , with the high point being Bald Mountain in southern Douglas County. This peak can be seen from I-25 just northeast of Monument Hill. This ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photometry (astronomy)
Photometry, from Greek '' photo-'' ("light") and '' -metry'' ("measure"), is a technique used in astronomy that is concerned with measuring the flux or intensity of light radiated by astronomical objects. This light is measured through a telescope using a photometer, often made using electronic devices such as a CCD photometer or a photoelectric photometer that converts light into an electric current by the photoelectric effect. When calibrated against standard stars (or other light sources) of known intensity and colour, photometers can measure the brightness or apparent magnitude of celestial objects. The methods used to perform photometry depend on the wavelength region under study. At its most basic, photometry is conducted by gathering light and passing it through specialized photometric optical bandpass filters, and then capturing and recording the light energy with a photosensitive instrument. Standard sets of passbands (called a photometric system) are defined to allow a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kitt Peak National Observatory
The Kitt Peak National Observatory (KPNO) is a United States astronomy, astronomical observatory located on Kitt Peak of the Quinlan Mountains in the Arizona-Sonoran Desert on the Tohono Oʼodham Nation, west-southwest of Tucson, Arizona. With more than twenty optical and two radio telescopes, it is one of the largest gatherings of astronomical instruments in the Earth's northern hemisphere. Kitt Peak National Observatory was founded in 1958. It is home to what was the largest solar telescope in the world, and many large astronomical telescopes of the late 20th century in the United States. The observatory was administered by the National Optical Astronomy Observatory (NOAO) from the early 1980s until 2019, after which it was overseen by NOIRLab. In June 2022, the Contreras Fire led to the evacuation of Kitt Peak. The fire reached the summit at 2 a.m. on Friday, June 17. Four non-scientific buildings, including a dormitory, were lost in the fire. As of Monday, June 20, the e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
South Africa
South Africa, officially the Republic of South Africa (RSA), is the southernmost country in Africa. It is bounded to the south by of coastline that stretch along the South Atlantic and Indian Oceans; to the north by the neighbouring countries of Namibia, Botswana, and Zimbabwe; and to the east and northeast by Mozambique and Eswatini. It also completely enclaves the country Lesotho. It is the southernmost country on the mainland of the Old World, and the second-most populous country located entirely south of the equator, after Tanzania. South Africa is a biodiversity hotspot, with unique biomes, plant and animal life. With over 60 million people, the country is the world's 24th-most populous nation and covers an area of . South Africa has three capital cities, with the executive, judicial and legislative branches of government based in Pretoria, Bloemfontein, and Cape Town respectively. The largest city is Johannesburg. About 80% of the population are Black South Afri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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