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Sagitta (other) ''. a genus of aquatic ...
Sagitta is a constellation, named after the Latin word for arrow. Sagitta may also refer to: * ''Sagitta'' (arrowworm), a genus of chaetognaths in the class Sagittoidea * Sagitta (geometry), the depth of an arc * Sagitta (optics), a measure of the glass removed to yield an optical curve * '' Ligularia sagitta'', a plant species * Sagitta, one of the otoliths, a structure in the inner ear of some fish * N.V. Vliegtuigbouw 013 Sagitta, a Dutch-designed glider that first flew in 1960 * USNS ''Sagitta'' (T-AK-87) (1944–1959) * Versine, a trigonometric function * Sagitta, pseudonym of Scottish-German author John Henry Mackay (1864–1993) See also * * Sagittal, in mathematics * ''Sagittaria ''Sagittaria'' is a genus of about 303. Sagittaria Linnaeus ''Flora of North ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sagitta
Sagitta is a dim but distinctive constellation in the northern sky. Its name is Latin for 'arrow', not to be confused with the significantly larger constellation Sagittarius 'the archer'. It was included among the 48 constellations listed by the 2nd-century astronomer Ptolemy, and it remains one of the 88 modern constellations defined by the International Astronomical Union. Although it dates to antiquity, Sagitta has no star brighter than 3rd magnitude and has the third-smallest area of any constellation. Gamma Sagittae is the constellation's brightest star, with an apparent magnitude of 3.47. It is an aging red giant star 90% as massive as the Sun that has cooled and expanded to a diameter 54 times greater than it. Delta, Epsilon, Zeta, and Theta Sagittae are each multiple stars whose components can be seen in small telescopes. V Sagittae is a cataclysmic variable—a binary star system composed of a white dwarf accreting mass of a donor star that is expected to go nova and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arrow
An arrow is a fin-stabilized projectile launched by a bow. A typical arrow usually consists of a long, stiff, straight shaft with a weighty (and usually sharp and pointed) arrowhead attached to the front end, multiple fin-like stabilizers called fletchings mounted near the rear, and a slot at the rear end called a nock for engaging the bowstring. A container or bag carrying additional arrows for convenient reloading is called a quiver. The use of bows and arrows by humans predates recorded history and is common to most cultures. A craftsman who makes arrows is a fletcher, and one that makes arrowheads is an arrowsmith.Paterson ''Encyclopaedia of Archery'' p. 56 History The oldest evidence of likely arrowheads, dating to c. 64,000 years ago, were found in Sibudu Cave, current South Africa.Backwell L, d'Errico F, Wadley L.(2008). Middle Stone Age bone tools from the Howiesons Poort layers, Sibudu Cave, South Africa. Journal of Archaeological Science, 35:1566–1580. Backwe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sagitta (arrowworm)
''Sagitta'' is a genus of Chaetognatha The Chaetognatha or chaetognaths (meaning ''bristle-jaws'') are a phylum of predatory marine worms that are a major component of plankton worldwide. Commonly known as arrow worms, about 20% of the known Chaetognatha species are benthic, and can ..., a phylum commonly known as arrowworms or arrow worms. Phylum Chaetognatha comprises small marine worms. This genus is characterized in part by the distribution of the cilia on the body, the thick rays in the fins, and hooks which are not serrated.Kassatkina, A. P. (2007)Review of the genera of the family Sagittidae with separation of a new subfamily and description of a new species of the genus ''Sagitta'' from the Sea of Japan (Chaetognatha).''Zoosystematica Rossica'', 16(2), 157-162. As of 2007 there are 15 species. More have since been described.Kassatkina, A. P. (2008)New species of the genus ''Sagitta sensu str''.(Chaetognatha) from the Sea of Japan with description of an original stain ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sagitta (geometry)
In geometry, the sagitta (sometimes abbreviated as sag) of a circular arc is the distance from the center of the arc to the center of its base. It is used extensively in architecture when calculating the arc necessary to span a certain height and distance and also in optics where it is used to find the depth of a spherical mirror or lens. The name comes directly from Latin ''sagitta'', meaning an arrow. Formulae In the following equations, denotes the sagitta (the depth or height of the arc), equals the radius of the circle, and the length of the chord spanning the base of the arc. As and are two sides of a right triangle with as the hypotenuse, the Pythagorean theorem gives us : r^2 = \left(\frac\right)^2 + \left(r-s\right)^2. This may be rearranged to give any of the other three: : \begin s &= r - \sqrt, \\ pxl &= 2\sqrt, \\ pxr &= \frac = \frac+\frac. \end The sagitta may also be calculated from the versine function, for an arc that spans an angle of , and coincides wi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sagitta (optics)
300x300px, Deep blue ray refers the radius of curvature and the red line segment is the sagitta of the curve (black). In optics and especially telescope making, sagitta or sag is a measure of the glass removed to yield an optical curve. It is approximated by the formula :: S(r) \approx \frac, where is the radius of curvature of the optical surface. The sag is the displacement along the optic axis of the surface from the vertex, at distance r from the axis. A good explanation both of this approximate formula and the exact formula can be founhere Aspheric surfaces Optical surfaces with non-spherical profiles, such as the surfaces of aspheric lenses, are typically designed such that their sag is described by the equation :S(r)=\frac+\alpha_1 r^2+\alpha_2 r^4+\alpha_3 r^6+\cdots . Here, K is the conic constant as measured at the vertex (where r=0). The coefficients \alpha_i describe the deviation of the surface from the axially symmetric quadric surface specified by R and K. Se ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ligularia
''Ligularia'' (leopard plant) is a genus of Old World herbaceous perennial plants in the groundsel tribe within the sunflower family. They have yellow or orange composite flower heads with brown or yellow central disc florets, and are native to damp habitats mostly in central and eastern Asia, with a few species from Europe. There are about 120Liu, J. Q., et al. (2006)Radiation and diversification within the ''Ligularia''–''Cremanthodium''–''Parasenecio'' complex (Asteraceae) triggered by uplift of the Qinghai-Tibetan Plateau.''Molecular Phylogenetics and Evolution'' 38(1) 31-49. to 140 species in the genus, and over half are endemic to China.Flora of China Vol. 20-21 Page 376 橐吾属 tuo wu shu ''Ligularia'' Cass. . The name ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Otolith
An otolith ( grc-gre, ὠτο-, ' ear + , ', a stone), also called statoconium or otoconium or statolith, is a calcium carbonate structure in the saccule or utricle of the inner ear, specifically in the vestibular system of vertebrates. The saccule and utricle, in turn, together make the ''otolith organs''. These organs are what allows an organism, including humans, to perceive linear acceleration, both horizontally and vertically (gravity). They have been identified in both extinct and extant vertebrates. Counting the annual growth rings on the otoliths is a common technique in estimating the age of fish. Description Endolymphatic infillings such as otoliths are structures in the saccule and utricle of the inner ear, specifically in the vestibular labyrinth of all vertebrates (fish, amphibians, reptiles, mammals and birds). In vertebrates, the saccule and utricle together make the ''otolith organs''. Both statoconia and otoliths are used as gravity, balance, movement, and d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
USNS Sagitta (T-AK-87)
''Sagitta'' (AK-87)Only USS Enceladus (AK-80), USS ''Enceladus'' (AK-80) of the ten ships of the ''Enceladus'' class, composed of Maritime Commission N3-M-A1 type small cargo vessels, saw significant naval service. Of the other nine, excpting USS Hydra (AK-82), USS ''Hydra'' (AK-82), all were transferred within months or days of shipyard delivery to Navy to the Army. ''Hydra'' was transferred to Army shortly after commissioning and trials. Navy had assumed the administration of contracts for these ships from the Maritime Commission on 1 January 1943 during or before construction and thus most were only administratively Navy, including names and numbers, during construction. was never commissioned and thus never bore the USS designation. The ship, contracted as the Maritime Commission MV ''Moses Pike'', transferred to Navy supervision for construction and was then transferred shortly after launch as ''Sagitta'' (AK-87) to the Army to become the U.S. Army Port Repair ship, Enginee ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Versine
The versine or versed sine is a trigonometric function found in some of the earliest (Sanskrit Āryabhaṭa's sine table , ''Aryabhatia'', Section I) trigonometric tables. The versine of an angle is 1 minus its cosine. There are several related functions, most notably the coversine and haversine. The latter, half a versine, is of particular importance in the haversine formula of navigation. Overview The versine or versed sine is a trigonometric function already appearing in some of ...[...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
John Henry Mackay
John Henry Mackay, also known by the pseudonym Sagitta, (6 February 1864 – 16 May 1933) was an egoist anarchist, thinker and writer. Born in Scotland and raised in Germany, Mackay was the author of '' Die Anarchisten'' (The Anarchists, 1891) and ''Der Freiheitsucher'' (The Searcher for Freedom, 1921). Biography Mackay was born in Greenock, Scotland, on 6 February 1864. His mother came from a prosperous Hamburg family. His father was a Scottish marine insurance broker who died when Mackay was less than two years old. Mother and son then returned to Germany, where Mackay grew up. He gained fame as a poet and author of naturalist novels. Some of his earliest poems attracted the attention of censors for their socialist sentiments, so Mackay republished them in Switzerland. During a one-year stay in London (1887/88), he discovered the works of Max Stirner, whose book (''The Ego and its Own'') had nearly been forgotten in the second half of the 19th century. Stirner soon became hi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sagittal
The sagittal plane (; also known as the longitudinal plane) is an anatomical plane that divides the body into right and left sections. It is perpendicular to the transverse and coronal planes. The plane may be in the center of the body and divide it into two equal parts ( mid-sagittal), or away from the midline and divide it into unequal parts (para-sagittal). The term ''sagittal'' was coined by Gerard of Cremona. Variations in terminology Examples of sagittal planes include: * The terms ''median plane'' or ''mid-sagittal plane'' are sometimes used to describe the sagittal plane running through the midline. This plane cuts the body into halves (assuming bilateral symmetry), passing through midline structures such as the navel and spine. It is one of the planes which, combined with the Umbilical plane, defines the four quadrants of the human abdomen. * The term ''parasagittal'' is used to describe any plane parallel or adjacent to a given sagittal plane. Specific named parasag ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sagittaria
''Sagittaria'' is a genus of about 303. Sagittaria Linnaeus ''Flora of North America'' species of aquatic plants whose members go by a variety of common names, including arrowhead, duck potato, katniss, Omodaka (沢瀉 in Japanese), swamp potato, tule potato, and wapato (or wapatoo). Most are native to South America, South, Central America, Central, and North America, but there are also some from Europe, Africa, and Asia. Description Sagittaria plant stock (the perennial rhizome) is a horizontal creeper (stoloniferous) and obliquely obovate, the margins winged, with apical or ventral beak; in other words, they are a small, dry, one-seeded fruit that do not open to release the seed, set on a slant, narrower at the base, with winged edges, and havi ...[...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
