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Eta Carinae
Eta Carinae (η Carinae, abbreviated to η Car), formerly known as Eta Argus, is a stellar system containing at least two stars with a combined luminosity greater than five million times that of the Sun, located around distant in the constellation Carina. Previously a 4th-magnitude star, it brightened in 1837 to become brighter than Rigel, marking the start of its so-called "Great Eruption". It became the second-brightest star in the sky between 11 and 14 March 1843 before fading well below naked eye visibility after 1856. In a smaller eruption, it reached 6th magnitude in 1892 before fading again. It has brightened consistently since about 1940, becoming brighter than magnitude 4.5 by 2014. At declination −59° 41′ 04.26″, Eta Carinae is circumpolar from locations on Earth south of latitude 30°S, (for reference, the latitude of Johannesburg is 26°12′S); and is not visible north of about latitude 30°N, just south of Cairo, which is at a latitude ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eta Carinae
Eta Carinae (η Carinae, abbreviated to η Car), formerly known as Eta Argus, is a stellar system containing at least two stars with a combined luminosity greater than five million times that of the Sun, located around distant in the constellation Carina. Previously a 4th-magnitude star, it brightened in 1837 to become brighter than Rigel, marking the start of its so-called "Great Eruption". It became the second-brightest star in the sky between 11 and 14 March 1843 before fading well below naked eye visibility after 1856. In a smaller eruption, it reached 6th magnitude in 1892 before fading again. It has brightened consistently since about 1940, becoming brighter than magnitude 4.5 by 2014. At declination −59° 41′ 04.26″, Eta Carinae is circumpolar from locations on Earth south of latitude 30°S, (for reference, the latitude of Johannesburg is 26°12′S); and is not visible north of about latitude 30°N, just south of Cairo, which is at a latitude ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Boss General Catalogue
''Boss General Catalogue'' (''GC'', sometimes General Catalogue) is an astronomical catalogue containing 33,342 stars. It was compiled by Benjamin Boss and published in the United States in 1936. Its original name was ''General Catalogue of 33,342 Stars'' and it superseded the previous ''Preliminary General Catalogue of 6,188 Stars for the Epoch 1900'' published in 1910 by Benjamin's father Lewis Boss Lewis Boss (26 October 1846 – 5 October 1912) was an American astronomer. He served as the director of the Dudley Observatory in Schenectady, New York. Early life Boss was born in Providence, Rhode Island to Samuel P. and Lucinda (née J .... Astronomical catalogues of stars 1910 non-fiction books 1936 non-fiction books 1930s in science 1910s in science 1936 in science 1910 in science 1900 in science {{astronomy-book-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
30th Parallel North
The 30th parallel north is a circle of latitude that is 30 degrees north of the Earth's equatorial plane. It stands one-third of the way between the equator and the North Pole and crosses Africa, Asia, the Pacific Ocean, North America and the Atlantic Ocean. The parallel is used in some contexts to delineate Europe or what is associated with the continent of Europe as a southernmost limit, e.g. to qualify for membership of the European Broadcasting Union. It is the approximate southern border of the horse latitudes in the Northern Hemisphere, meaning that much of the land area touching the 30th parallel is arid or semi-arid. If there is a source of wind from a body of water the area would more likely be humid subtropical. At this latitude the sun is visible for 14 hours, 5 minutes during the summer solstice and 10 hours, 13 minutes during the winter solstice, and the nighttime duration lasts 9 hours, 55 minutes during the summer solstice and 13 hours, 47 minutes during the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Johannesburg
Johannesburg ( , , ; Zulu and xh, eGoli ), colloquially known as Jozi, Joburg, or "The City of Gold", is the largest city in South Africa, classified as a megacity, and is one of the 100 largest urban areas in the world. According to Demographia, the Johannesburg–Pretoria urban area (combined because of strong transport links that make commuting feasible) is the 26th-largest in the world in terms of population, with 14,167,000 inhabitants. It is the provincial capital and largest city of Gauteng, which is the wealthiest province in South Africa. Johannesburg is the seat of the Constitutional Court, the highest court in South Africa. Most of the major South African companies and banks have their head offices in Johannesburg. The city is located in the mineral-rich Witwatersrand range of hills and is the centre of large-scale gold and diamond trade. The city was established in 1886 following the discovery of gold on what had been a farm. Due to the extremely large gold ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
30th Parallel South
The 30th parallel south is a circle of latitude that is 30 degrees south of the Earth's equator. It stands one-third of the way between the equator and the South Pole and crosses Africa, the Indian Ocean, Australia, the Pacific Ocean, South America and the Atlantic Ocean. At this latitude the sun is visible for 14 hours, 5 minutes during the summer solstice and 10 hours, 13 minutes during the winter solstice. On December 21, the sun is at 83.83 degrees up in the sky and at 36.17 degrees on June 21. Around the world Starting at the Prime Meridian and heading eastwards, the parallel 30° south passes through: : See also *29th parallel south *31st parallel south *30th parallel north {{geographical coordinates, state=collapsed s30 S30 may refer to: Automobiles * Aeolus S30, a Chinese sedan * Jinbei S30, a Chinese SUV * Nissan S30, a Japanese sport car * Toyota Crown (S30), a Japanese sedan Aviation * Blériot-SPAD S.30, a French sport aircraft * Lebanon State Air ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Circumpolar Star
A circumpolar star is a star that, as viewed from a given latitude on Earth, never sets below the horizon due to its apparent proximity to one of the celestial poles. Circumpolar stars are therefore visible from said location toward the nearest pole for the entire night on every night of the year (and would be continuously visible throughout the day too, were they not overwhelmed by the Sun's glare). Others are called ''seasonal'' stars. All circumpolar stars lie within a circumpolar circle whose size is determined by the observer's latitude. Specifically, the angular measure of the radius of this circle equals the observer's latitude. The closer the observer is to the North or South Pole, the larger the circumpolar circle is. Before the definition of the Arctic was formalized as the region north of the Arctic Circle which experiences the Midnight sun, it more broadly meant those places where the 'bear' constellations (Ursa Major, the Great Bear, and Ursa Minor, the Little Bea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Naked Eye
Naked eye, also called bare eye or unaided eye, is the practice of engaging in visual perception unaided by a magnifying, light-collecting optical instrument, such as a telescope or microscope, or eye protection. Vision corrected to normal acuity using corrective lenses is still considered "naked". In astronomy, the naked eye may be used to observe celestial events and objects visible without equipment, such as conjunctions, passing comets, meteor showers, and the brightest asteroids, including 4 Vesta. Sky lore and various tests demonstrate an impressive variety of phenomena visible to the unaided eye. Basic properties Some basic properties of the human eye are: *Quick autofocus from distances of 25 cm (young people) to 50 cm (most people 50 years and older) to infinity. * Angular resolution: about 1 arcminute, approximately 0.017° or 0.0003 radians, which corresponds to 0.3 m at a 1 km distance. *Field of view (FOV): simultaneous visual perc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Brightest Stars
This is a list of stars arranged by their apparent magnitude – their brightness as observed from Earth. It includes all stars brighter than magnitude +2.50 in visible light, measured using a ''V''-band filter in the UBV photometric system. Stars in binary systems (or other multiples) are listed by their ''total'' or ''combined'' brightness if they appear as a single star to the naked eye, or listed separately if they do not. As with all magnitude systems in astronomy, the scale is logarithmic and inverted i.e. lower/more negative numbers are brighter. Most stars on this list appear bright from Earth because they are nearby, not because they are intrinsically luminous. For a list which compensates for the distances, converting the ''apparent'' magnitude to the ''absolute'' magnitude, see the list of most luminous stars. Measurement The Sun is the brightest star as viewed from Earth, at −26.74 mag. The second brightest is Sirius at −1.46 mag. For c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rigel
Rigel is a blue supergiant star in the constellation of Orion. It has the Bayer designation β Orionis, which is Latinized to Beta Orionis and abbreviated Beta Ori or β Ori. Rigel is the brightest and most massive componentand the eponymof a star system of at least four stars that appear as a single blue-white point of light to the naked eye. This system is located at a distance of approximately from the Sun. A star of spectral type B8Ia, Rigel is calculated to be anywhere from 61,500 to 363,000 times as luminous as the Sun, and 18 to 24 times as massive, depending on the method and assumptions used. Its radius is more than seventy times that of the Sun, and its surface temperature is . Due to its stellar wind, Rigel's mass-loss is estimated to be ten million times that of the Sun. With an estimated age of seven to nine million years, Rigel has exhausted its core hydrogen fuel, expanded, and cooled to become a supergiant. It is expected to end its life a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apparent Magnitude
Apparent magnitude () is a measure of the brightness of a star or other astronomical object observed from Earth. An object's apparent magnitude depends on its intrinsic luminosity, its distance from Earth, and any extinction of the object's light caused by interstellar dust along the line of sight to the observer. The word ''magnitude'' in astronomy, unless stated otherwise, usually refers to a celestial object's apparent magnitude. The magnitude scale dates back to the ancient Roman astronomer Claudius Ptolemy, whose star catalog listed stars from 1st magnitude (brightest) to 6th magnitude (dimmest). The modern scale was mathematically defined in a way to closely match this historical system. The scale is reverse logarithmic: the brighter an object is, the lower its magnitude number. A difference of 1.0 in magnitude corresponds to a brightness ratio of \sqrt /math>, or about 2.512. For example, a star of magnitude 2.0 is 2.512 times as bright as a star of magnitude 3.0, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Constellation
A constellation is an area on the celestial sphere in which a group of visible stars forms a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object. The origins of the earliest constellations likely go back to prehistory. People used them to relate stories of their beliefs, experiences, creation, or mythology. Different cultures and countries adopted their own constellations, some of which lasted into the early 20th century before today's constellations were internationally recognized. The recognition of constellations has changed significantly over time. Many changed in size or shape. Some became popular, only to drop into obscurity. Some were limited to a single culture or nation. The 48 traditional Western constellations are Greek. They are given in Aratus' work ''Phenomena'' and Ptolemy's '' Almagest'', though their origin probably predates these works by several centuries. Constellations in the far southern sky were ad ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Luminosity
Luminosity is an absolute measure of radiated electromagnetic power (light), the radiant power emitted by a light-emitting object over time. In astronomy, luminosity is the total amount of electromagnetic energy emitted per unit of time by a star, galaxy, or other astronomical object. In SI units, luminosity is measured in joules per second, or watts. In astronomy, values for luminosity are often given in the terms of the luminosity of the Sun, ''L''⊙. Luminosity can also be given in terms of the astronomical magnitude system: the absolute bolometric magnitude (''M''bol) of an object is a logarithmic measure of its total energy emission rate, while absolute magnitude is a logarithmic measure of the luminosity within some specific wavelength range or filter band. In contrast, the term ''brightness'' in astronomy is generally used to refer to an object's apparent brightness: that is, how bright an object appears to an observer. Apparent brightness depends on both the lum ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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