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Diopter Sight
The diopter is an aperture sight component used to assist the aiming of devices, mainly firearms, airguns, and crossbows. It is found in particular as a rear sight element on rifles. To obtain a usable sighting line the diopter has to have a complementing front sight element. Diopter and globe sighting lines are commonly used in ISSF match rifle shooting events. Diopter rear sight The diopter is in principle a vertically and horizontally (elevation and windage) adjustable occluder with a small hole (aperture), and is placed close in front of the shooter's aiming eye. Through this small hole the shooter can view the front sight component(s) and the intended target. The typical occluder used in target shooting diopters is a disc of about in diameter with a small hole in the middle. The small diopter viewing opening ensures the shooter's eye is very precisely and consistently centered behind the diopter sight. The diopter sight is easy to use and usually allows for very accu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diopter
A dioptre (British spelling) or diopter (American spelling) is a unit of measurement with dimension of reciprocal length, equivalent to one reciprocal metre, 1 dioptre = 1 m−1. It is normally used to express the optical power of a lens or curved mirror, which is a physical quantity equal to the reciprocal of the focal length, expressed in metres. For example, a 3-dioptre lens brings parallel rays of light to focus at metre. A flat window has an optical power of zero dioptres, as it does not cause light to converge or diverge. Dioptres are also sometimes used for other reciprocals of distance, particularly radii of curvature and the vergence of optical beams. The main benefit of using optical power rather than focal length is that the thin lens formula has the object distance, image distance, and focal length all as reciprocals. Additionally, when relatively thin lenses are placed close together their powers approximately add. Thus, a thin 2.0-dioptre lens placed close to a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iris Diaphragm
In optics, a diaphragm is a thin opaque structure with an opening (aperture) at its center. The role of the diaphragm is to ''stop'' the passage of light, except for the light passing through the ''aperture''. Thus it is also called a stop (an aperture stop, if it limits the brightness of light reaching the focal plane, or a field stop or flare stop for other uses of diaphragms in lenses). The diaphragm is placed in the light path of a lens or objective, and the size of the aperture regulates the amount of light that passes through the lens. The centre of the diaphragm's aperture coincides with the optical axis of the lens system. Most modern cameras use a type of adjustable diaphragm known as an iris diaphragm, and often referred to simply as an iris. See the articles on aperture and f-number for the photographic effect and system of quantification of varying the opening in the diaphragm. Iris diaphragms versus other types A natural optical system that has a diaphrag ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Warrior Games
The Warrior Games is a multi-sport event for wounded, injured or ill service personnel and veterans organized by the United States Department of Defense (DoD). History 2010–2014 The Warrior Games have taken place annually since 2010. It was created by John Wordin working with Gen. Gary Cheek (U.S. Army) while participating in the Ride 2 Recovery 2009 Texas Challenge. Subsequently, a meeting was held at the Pentagon with USO (Sloan Gibson, Kevin Wensing, Jeff Hill) Gen Cheek, Gen. David Blackledge and Sgt. James Shriver. Soon USMC Col. Greg Boyle and the United States Olympic Committee got involved too. The first event was hosted at the U.S. Olympic and Paralympic Training Center in Colorado Springs, Colorado, which continued to host the event through to 2014. Teams from the Army, Marine Corps, Navy/Coast Guard, Air Force, Special Operations Command took part, competing in adaptive sports events. Athletes from the British Armed Forces took part in 2013, the first allie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Feinwerkbau
Feinwerkbau , often abbreviated FWB, is a German manufacturer of firearms and air guns aimed mainly at competitive ISSF shooting events, including some contested at the Olympic Games as governed by the International Shooting Sport Federation (ISSF). The company currently offers three distinct product lines: air pistols and rifles, small caliber .177 and .22 lr rifles and competition pistols as well as two muzzleloading black powder smallarms, chambered in .36 and .44. It also offers several accessories, an archery trigger release and high-precision industrial machining and manufacturing services. Feinwerkbau has on-site service staff available at various European shooting events. The name Feinwerkbau is German, which translates to "precision technology works". History The company was established 1949 by Karl Westinger and Ernst Altenburger, both former employees of Mauser where Westinger had been responsible for an important design improvement to the Mauser C96 “Broomhandl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hattie Johnson
Hattie Johnson (née Ponti; born September 18, 1981) is a former Olympic athlete. The Athol, Idaho, resident competed in the Women's 10-metre Air Rifle at the 2004 Summer Olympics in Athens, Greece, finishing in 14th place. In 2003 Pan American Games, she won a bronze medal in the Women's 50-meter Rifle 3 Positions Event. At the 2004 Summer Olympics, Johnson competed while a member of the United States Army. She was then a medical Spc., assigned to the Marksmanship Unit at Fort Benning, Georgia Georgia most commonly refers to: * Georgia (country), a country in the Caucasus region of Eurasia * Georgia (U.S. state), a state in the Southeast United States Georgia may also refer to: Places Historical states and entities * Related to the .... References External links Johnson Places 14th in Olympic Air Rifle Competition 1981 births American female sport shooters Living people Olympic shooters of the United States ISSF rifle shooters Shooters at the 2004 Summ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
10 Metre Air Rifle
10 metre air rifle (N.B. For "Meter" in this article – read "Metre") is an International Shooting Sports Federation (ISSF) shooting event, shot at a bullseye target over a distance of using a calibre air rifle with a maximum weight of . It is one of the ISSF-governed shooting sports included in the Summer Olympics since the 1984 Los Angeles Games. Shots are fired from the standing position only, as opposed to some other airgun disciplines such as for three positions (popular in the United States) or in disabled sports, which allows sitting and prone positions. Due to the low recoil of air guns and the need for stability, the shooter frequently adopts a deliberately lordotic and scoliotic posture, which allows the non-dominant elbow to be rested against the chest to support the forearm and improves the stability of the shooting stance. The use of specialized rigidly padded vest is allowed to prevent chronic back injury, which can be caused by prolonged asymmetric load ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Concentric
In geometry, two or more objects are said to be concentric, coaxal, or coaxial when they share the same center or axis. Circles, regular polygons and regular polyhedra, and spheres may be concentric to one another (sharing the same center point), as may cylinders (sharing the same central axis). Geometric properties In the Euclidean plane, two circles that are concentric necessarily have different radii from each other.. However, circles in three-dimensional space may be concentric, and have the same radius as each other, but nevertheless be different circles. For example, two different meridians of a terrestrial globe are concentric with each other and with the globe of the earth (approximated as a sphere). More generally, every two great circles on a sphere are concentric with each other and with the sphere. By Euler's theorem in geometry on the distance between the circumcenter and incenter of a triangle, two concentric circles (with that distance being zero) are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diopter Sight Picture
A dioptre ( British spelling) or diopter ( American spelling) is a unit of measurement with dimension of reciprocal length, equivalent to one reciprocal metre, 1 dioptre = 1 m−1. It is normally used to express the optical power of a lens or curved mirror, which is a physical quantity equal to the reciprocal of the focal length, expressed in metres. For example, a 3-dioptre lens brings parallel rays of light to focus at metre. A flat window has an optical power of zero dioptres, as it does not cause light to converge or diverge. Dioptres are also sometimes used for other reciprocals of distance, particularly radii of curvature and the vergence of optical beams. The main benefit of using optical power rather than focal length is that the thin lens formula has the object distance, image distance, and focal length all as reciprocals. Additionally, when relatively thin lenses are placed close together their powers approximately add. Thus, a thin 2.0-dioptre lens placed close t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transparency (optics)
In the field of optics, transparency (also called pellucidity or diaphaneity) is the physical property of allowing light to pass through the material without appreciable scattering of light. On a macroscopic scale (one in which the dimensions are much larger than the wavelengths of the photons in question), the photons can be said to follow Snell's law. Translucency (also called translucence or translucidity) allows light to pass through, but does not necessarily (again, on the macroscopic scale) follow Snell's law; the photons can be scattered at either of the two interfaces, or internally, where there is a change in index of refraction. In other words, a translucent material is made up of components with different indices of refraction. A transparent material is made up of components with a uniform index of refraction. Transparent materials appear clear, with the overall appearance of one color, or any combination leading up to a brilliant spectrum of every color. The opposite ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cylinder (geometry)
A cylinder (from ) has traditionally been a three-dimensional solid, one of the most basic of curvilinear geometric shapes. In elementary geometry, it is considered a prism with a circle as its base. A cylinder may also be defined as an infinite curvilinear surface in various modern branches of geometry and topology. The shift in the basic meaning—solid versus surface (as in ball and sphere)—has created some ambiguity with terminology. The two concepts may be distinguished by referring to solid cylinders and cylindrical surfaces. In the literature the unadorned term cylinder could refer to either of these or to an even more specialized object, the ''right circular cylinder''. Types The definitions and results in this section are taken from the 1913 text ''Plane and Solid Geometry'' by George Wentworth and David Eugene Smith . A ' is a surface consisting of all the points on all the lines which are parallel to a given line and which pass through a fixed plane curve in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Globe Sight
A globe sight is a front sight component used to assist the aiming of a gun/device, usually those intended to launch projectiles, such as firearms, airguns, and crossbows. It is found in particular as a front sight element on rifles. To obtain a usable sighting line the diopter has to have a complementing rear sight element. Diopter and globe sighting lines are commonly used in ISSF match rifle shooting events. Globe front sight The globe front sight consists of a hollow cylinder with a threaded cap, which allows differently shaped interchangeable front sight elements to be used. Most common are posts of varying widths and heights or rings or holes of varying diameter — these can be chosen by the shooter for the best fit to the target being used. Tinted transparent plastic insert elements may also be used, with a hole in the middle; these work the same way as an opaque ring, but provide a less obstructed view of the target. High end target front sight tunnels normally a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Contrast (vision)
Contrast is the contradiction in luminance or colour that makes an object (or its representation in an image or display) distinguishable. In visual perception of the real world, contrast is determined by the difference in the color, colour and brightness of the object and other objects within the same field of view. The human visual system is more sensitive to contrast than absolute luminance; we can perceive the world similarly regardless of the huge changes in illumination over the day or from place to place. The maximum ''contrast'' of an image is the contrast ratio or dynamic range. Images with a contrast ratio close to their medium's maximum possible contrast ratio experience a ''conservation of contrast'', wherein any increase in contrast in some parts of the image must necessarily result in a decrease in contrast elsewhere. Brightening an image will increase contrast in dark areas but decrease contrast in bright areas, while darkening the image will have the opposite effec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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