|
Triangulum Galaxy
The Triangulum Galaxy is a spiral galaxy 2.73 million light-years (ly) from Earth in the constellation Triangulum. It is catalogued as Messier 33 or NGC (''New General Catalogue)'' 598. With the D25 isophotal diameter of , the Triangulum Galaxy is the third-largest member of the Local Group of galaxies, behind the Andromeda Galaxy and the Milky Way. The galaxy is the smallest spiral galaxy in the Local Group (although the smaller Large and Small Magellanic Clouds may have been spirals before their encounters with the Milky Way), and is believed to be a satellite of the Andromeda Galaxy or on its rebound into the latter due to their interactions, velocities, and proximity to one another in the night sky. It also has an H II nucleus. Etymology The galaxy gets its name from the constellation Triangulum, where it can be spotted. It is sometimes informally referred to as the "Pinwheel Galaxy" by some astronomy references, in some computerized telescope software, and in some pub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
VST Snaps A Very Detailed View Of The Triangulum Galaxy
VST may refer to: * Vancouver School of Theology, a theological graduate school in British Columbia, Canada * VST, Stockholm Västerås Airport in Sweden (IATA airport code) * Vehicle safety technology * Virtual Studio Technology, Steinberg's standard for audio plug-ins ** in particular, may refer to some versions of the Steinberg Cubase program * Towner Railway (reporting mark) * VLT Survey Telescope, a wide-field telescope on Cerro Paranal, Chile * Venezuela Standard Time, Venezuela's time zone * VST Industries, Hyderabad, India * VST (album), ''VST'' (album) * Public Security Service (Lithuania), Public Security Service, a Lithuanian law enforcement agency {{Disamb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Small Magellanic Cloud
The Small Magellanic Cloud (SMC), or Nubecula Minor, is a dwarf galaxy near the Milky Way. Classified as a dwarf irregular galaxy, the SMC has a D25 isophotal diameter of about , and contains several hundred million stars. It has a total mass of approximately 7 billion solar masses. At a distance of about 200,000 light-years, the SMC is among the nearest intergalactic neighbors of the Milky Way and is one of the most distant objects visible to the naked eye. The SMC is visible from the entire Southern Hemisphere, but can be fully glimpsed low above the southern horizon from latitudes south of about 15° north. The galaxy is located across both the constellations of Tucana and part of Hydrus, appearing as a faint hazy patch resembling a detached piece of the Milky Way. The SMC has an average apparent diameter of about 4.2° (8 times the Moon's) and thus covers an area of about 14 square degrees (70 times the Moon's). Since its surface brightness is very low, this deep-sky object ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
De Systemate Orbis Cometici, Deque Admirandis Coeli Characteribus
''De systemate orbis cometici, deque admirandis coeli characteribus'' (transl. ''Of the systematics of the world of comets, and on the admirable objects of the sky'') is a small tract on comets and other celestial objects by the Sicilian astronomer Giovanni Battista Hodierna published in 1654. It contains a catalogue of comets and other celestial objects, but had limited circulation and the work was forgotten until 1985. In this work, Hodierna expressed the belief that comets were made of a more terrestrial substance, and considered nebulae to be made up of stars (''Lux Primogenita''). Scope The first part of his work (''De systemate orbis cometici'') followed Galileo's ideas on comets. The second part (''De admirandis coeli characteribus'') consisted of four main sections. The first concerns the classification of nebulaes. Hodierna classified the objects into three types according to their resolvability. ''Luminosae'', or star clusters to the naked eye, ''Nebulae'', or clusters ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Giovanni Battista Hodierna
Giovanni Battista Hodierna, also spelled as Odierna (April 13, 1597 – April 6, 1660) was an Italian astronomer at the court of Giulio Tomasi, Duke of Palma (Palma di Montechiaro). He compiled a catalogue of comets and other celestial objects containing some 40 entries, including at least 19 real and verifiable nebulous objects that might be confused with comets. Biography Hodierna was born in Ragusa, Sicily and died in Palma di Montechiaro. While serving as a Roman Catholic priest in Ragusa, he also practised astronomy. In 1654 he published a book entitled '' De systemate orbis cometici, deque admirandis coeli characteribus'' that contained a catalogue of celestial objects. The work anticipated Messier's catalogue, but had little impact. Messier seems not to have known of it. Hodierna was prolific in publication, and his interests spanned many disciplines. In addition to his astronomical observations, he utilized optic microscopes to study insects, publishing on the m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bortle Dark-Sky Scale
The Bortle scale (also known as the Bottle scale) is a nine-level numeric scale that measures the night sky's brightness of a particular location. It quantifies the astronomical observability of celestial objects and the interference caused by light pollution. John E. Bortle created the scale and published it in the February 2001 edition of ''Sky & Telescope'' magazine to help amateur astronomers evaluate the darkness of an observing site, and secondarily, to compare the darkness of observing sites. The scale ranges from Class 1, the darkest skies available on Earth, through to Class 9, inner-city skies. It gives several criteria for each level beyond naked-eye limiting magnitude (NELM). The accuracy and utility of the scale have been questioned in recent research. The table below summarizes Bortle's descriptions of the classes. Some classes can have very drastic differences from the one next to it, e.g, Bortle 4 to 5. In popular culture The band Days N' Daze referenced the scale ... [...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 percepti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
20/20 Vision
Visual acuity (VA) commonly refers to the clarity of vision, but technically rates an examinee's ability to recognize small details with precision. Visual acuity is dependent on optical and neural factors, i.e. (1) the sharpness of the retinal image within the eye, (2) the health and functioning of the retina, and (3) the sensitivity of the interpretative faculty of the brain. The most commonly referred visual acuity is the far acuity (e.g. 6/6 or 20/20 acuity), which describes the examinee's ability to recognize small details at a far distance, and is relevant to people with myopia; however, for people with hyperopia, the near acuity is used instead to describe the examinee's ability to recognize small details at a near distance. A common cause of low visual acuity is refractive error (ametropia), errors in how the light is refracted in the eyeball, and errors in how the retinal image is interpreted by the brain. The latter is the primary cause for low vision in people with al ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Light Pollution
Light pollution is the presence of unwanted, inappropriate, or excessive use of artificial Visible spectrum, lighting. In a descriptive sense, the term ''light pollution'' refers to the effects of any poorly implemented lighting, during the day or night. Light pollution can be understood not only as a phenomenon resulting from a specific source or kind of pollution, but also as a contributor to the wider, collective impact of various sources of pollution. Although this type of pollution can exist throughout the day, its effects are magnified during the night with the contrast of darkness. It has been estimated that 83 percent of the world's people live under light-polluted skies and that 23 percent of the world's land area is affected by skyglow. The area affected by artificial illumination continues to increase. A major side-effect of urbanization, light pollution is blamed for compromising health, disrupting ecosystems, and spoiling aesthetic environments. Globally, it has incr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ursa Major
Ursa Major (; also known as the Great Bear) is a constellation in the northern sky, whose associated mythology likely dates back into prehistory. Its Latin name means "greater (or larger) bear," referring to and contrasting it with nearby Ursa Minor, the lesser bear. In antiquity, it was one of the original 48 constellations listed by Ptolemy in the 2nd century AD, drawing on earlier works by Greek, Egyptian, Babylonian, and Assyrian astronomers. Today it is the third largest of the 88 modern constellations. Ursa Major is primarily known from the asterism of its main seven stars, which has been called the "Big Dipper," "the Wagon," "Charles's Wain," or "the Plough," among other names. In particular, the Big Dipper's stellar configuration mimics the shape of the "Little Dipper." Two of its stars, named Dubhe and Merak ( α Ursae Majoris and β Ursae Majoris), can be used as the navigational pointer towards the place of the current northern pole star, Polaris in Ursa Mino ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pinwheel Galaxy
The Pinwheel Galaxy (also known as Messier 101, M101 or NGC 5457) is a face-on spiral galaxy away from Earth in the constellation Ursa Major. It was discovered by Pierre Méchain in 1781 and was communicated that year to Charles Messier, who verified its position for inclusion in the ''Messier Catalogue'' as one of its final entries. On February 28, 2006, NASA and the European Space Agency released a very detailed image of the Pinwheel Galaxy, which was the largest and most-detailed image of a galaxy by Hubble Space Telescope at the time. The image was composed of 51 individual exposures, plus some extra ground-based photos. On August 24, 2011, a Type Ia supernova, SN 2011fe, was discovered in M101. Discovery Pierre Méchain, the discoverer of the galaxy, described it as a "nebula without star, very obscure and pretty large, 6' to 7' in diameter, between the left hand of Bootes and the tail of the great Bear. It is difficult to distinguish when one lits the [grating] wires ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SIMBAD Astronomical Database
SIMBAD (the Set of Identifications, Measurements and Bibliography for Astronomical Data) is an astronomical database of objects beyond the Solar System. It is maintained by the Centre de données astronomiques de Strasbourg (CDS), France. SIMBAD was created by merging the Catalog of Stellar Identifications (CSI) and the Bibliographic Star Index as they existed at the Meudon Computer Centre until 1979, and then expanded by additional source data from other catalogues and the academic literature. The first on-line interactive version, known as Version 2, was made available in 1981. Version 3, developed in the C language and running on UNIX stations at the Volgograd Observatory, was released in 1990. Fall of 2006 saw the release of Version 4 of the database, now stored in PostgreSQL, and the supporting software, now written entirely in Java. JP11 is a star catalogue containing about 4,000 objects. Currently it exists only as a part of the SIMBAD database. , SIMBAD contains informa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
.jpg "Click for more on -> Small Magellanic Cloud")
