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Stadiametric Reticle
Stadiametric rangefinding, or the stadia method, is a technique of measuring distances with a telescopic instrument. The term stadia comes from a Greek unit of length '' Stadion'' (equal to 600 Greek feet, ''pous'') which was the typical length of a sports stadium of the time. Stadiametric rangefinding is used for surveying and in the telescopic sights of firearms, artillery pieces, or tank guns, as well as some binoculars and other optics. It is still widely used in long-range military sniping, but in many professional applications it is being replaced with microwave, infrared, or laser rangefinding methods. Although much easier to use, electronic rangefinders can give away the shooter's position to a well-equipped adversary, and the need for accurate range estimation existed for much longer than electronic rangefinders small and rugged enough to be suitable for military use. Principle The stadia method is based upon the principle of similar triangles. This means that, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PSO-1
Russian PSO-1M2 current military issue 4×24 telescopic sight View through a PSO-1 telescopic sight mounted on an SVD rifle The PSO-1 (''Прицел Снайперский Оптический, Pritsel Snaipersky Optichesky'', "Optical Sniper Sight") is a 4×24 telescopic sight manufactured in Russia by the Novosibirsk instrument-making factory (NPZ Optics State Plant) and issued with the Russian military Dragunov sniper rifle. It was introduced on 3 July 1963 together with the Dragunov sniper rifle. Design The PSO-1 was specifically designed for the SVD as a telescopic sight for military designated marksman activities. The current version of the sight is the PSO-1M2. This telescopic sight is different from the original PSO-1 only in that it lacks the now obsolete infrared detector, which was used to detect generation-zero active-infrared night vision devices like the US M2 Sniperscope. The metal body of the PSO-1 is made from a magnesium alloy. The PSO-1 features a battery- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
M67 Sight Full-stadia Picture
M67, M-67, or M.67 may refer to: * M-67 (Michigan highway), a state highway in Michigan in the United States * M67 grenade, a fragmentation hand grenade * M67 motorway, a motorway in Greater Manchester, England * M67 recoilless rifle, an anti-tank weapon * The M-67 submachine gun; see MEMS M-52/60 * M67 Zippo, a flamethrower tank variant of the M48 Patton tank * BMW M67, a 1998 turbodiesel automobile engine * Mauser M67, a rifle made by Kongsberg Våpenfabrikk based on M/98k actions, which again were based on captured Karabiner 98k (K98k) actions * Macchi M.67 The Macchi M.67, was an Italian racing seaplane designed by Mario Castoldi and built by Macchi for the 1929 Schneider Trophy race. Design and development Castoldi based the design of the M.67, (a single-seat, low-wing, monoplane, twin-float floa ..., an Italian racing floatplane of 1929 * Messier 67, an open star cluster in the constellation Cancer {{Letter-NumberCombDisambig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Levelling
Levelling or leveling (American English; American and British English spelling differences#Doubled in British English, see spelling differences) is a branch of surveying, the object of which is to establish or verify or measure the height of specified points relative to a datum. It is widely used in geodesy and cartography to measure vertical position with respect to a vertical datum, and in construction to measure height differences of construction artifacts. Optical levelling Optical levelling, also known as spirit levelling and differential levelling, employs an ''optical level'', which consists of a precision telescope with crosshairs and stadia marks. The cross hairs are used to establish the level point on the target, and the stadia allow range-finding; stadia are usually at ratios of 100:1, in which case one metre between the stadia marks on the levelling staff represents 100metres from the target. The complete unit is normally mounted on a Tripod (surveying), tripod, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Graduation (instrument)
A graduation is a marking used to indicate points on a visual scale, which can be present on a container, a measuring device, or the axes of a line plot, usually one of many along a line or curve, each in the form of short line segments perpendicular to the line or curve. Often, some of these line segments are longer and marked with a numeral, such as every fifth or tenth graduation. The scale itself can be linear (the graduations are spaced at a constant distance apart) or nonlinear. Linear graduation of a scale occurs mainly (but not exclusively) on straight measuring devices, such as a rule or measuring tape, using units such as inches or millimetres. Graduations can also be spaced at varying spatial intervals, such as when using a logarithmic, for instance on a measuring cup, can vary in scale due to the container's non- cylindrical shape. Graduations along a curve Circular graduations of a scale occur on a circular arc or limb of an instrument. In some cases, non-circ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telescope
A telescope is a device used to observe distant objects by their emission, absorption, or reflection of electromagnetic radiation. Originally meaning only an optical instrument using lenses, curved mirrors, or a combination of both to observe distant objects, the word ''telescope'' now refers to a wide range of instruments capable of detecting different regions of the electromagnetic spectrum, and in some cases other types of detectors. The first known practical telescopes were refracting telescopes with glass lenses and were invented in the Netherlands at the beginning of the 17th century. They were used for both terrestrial applications and astronomy. The reflecting telescope, which uses mirrors to collect and focus light, was invented within a few decades of the first refracting telescope. In the 20th century, many new types of telescopes were invented, including radio telescopes in the 1930s and infrared telescopes in the 1960s. Etymology The word ''telescope'' was coin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stadia Mark
Stadia marks, also called stadia lines or stadia hairs, are crosshairs on the reticle of a theodolite or other surveying instrument that allow stadiametric rangefinding. Etymology The term stadia mark derives from the obsolete unit of distance, the stadion, derived from the Greek measurement of a stadium.Early Units of Measurement and the Nautical Mile, Commander Alton B. Moody, U.S.N.R. (U.S. Navy Hydrographic Office), pp 162-170, The Journal of Navigation / Volume 5 / Issue 3 / July 1952 . Several different stadia were defined, such as the Greek stadion and Egyptian stadion. Usage A typical surveyor's instrument reticle has two pairs of stadia marks. One pair are on the horizontal centreline and the other on the vertical cross hair. Each functions in the same manner and are placed for measuring on either axis. The stadia marks are set a specific length apart. This length is chosen so that there is a fixed, integer ratio between the difference of the rod readings and the d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Level Staff
{{short description, Graduated rod used to measure differences between heights A level staff, also called levelling rod, is a graduated wooden or aluminium rod, used with a levelling instrument to determine the difference in height between points or heights of points above a vertical datum. Rod construction and materials Levelling rods can be one piece, but many are sectional and can be shortened for storage and transport or lengthened for use. Aluminum rods may be shortened by telescoping sections inside each other, while wooden rod sections can be attached to each other with sliding connections or slip joints, or hinged to fold when not in use. There are many types of rods, with names that identify the form of the graduations and other characteristics. Markings can be in imperial or metric units. Some rods are graduated on one side only while others are marked on both sides. If marked on both sides, the markings can be identical or can have imperial units on one side and metric ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dumpy Level
A level is an optical instrument used to establish or verify points in the same horizontal plane in a process known as levelling, and is used in conjunction with a levelling staff to establish the relative height levels of objects or marks. It is widely used in surveying and construction to measure height differences and to transfer, measure, and set heights of known objects or marks. It is also known as a surveyor's level, builder's level, dumpy level or the historic "Y" level. It operates on the principle of establishing a visual level relationship between two or more points, for which an inbuilt telescope and a highly accurate bubble level are used to achieve the necessary accuracy. Traditionally the instrument was completely adjusted manually to ensure a level line of sight, but modern automatic versions self-compensate for slight errors in the coarse levelling of the instrument, and are thereby quicker to use. The optical level should not be confused with a theodolite, w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plane Table
A plane table (plain table prior to 1830) is a device used in surveying site mapping, exploration mapping, coastal navigation mapping, and related disciplines to provide a solid and level surface on which to make field drawings, charts and maps. The early use of the name ''plain table'' reflected its simplicity and plainness rather than its flatness. History The earliest mention of a plane table dates to 1551 in Abel Foullon's ''"Usage et description de l'holomètre"'', published in Paris.Turner, Anthony, ''Early Scientific Instruments, Europe 1400-1800'', Sotheby's Publishing, 1987, . page 81 However, since Foullon's description was of a complete, fully developed instrument, it must have been invented earlier. A brief description was also added to the 1591 edition of Digge's ''Pantometria''. The first mention of the device in English was by Cyprian Lucar in 1590.Turner, Gerard L'E., ''Scientific Instruments 1500-1900, An Introduction'', University of California Press, 1998 . ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Theodolite
A theodolite () is a precision optical instrument for measuring angles between designated visible points in the horizontal and vertical planes. The traditional use has been for land surveying, but it is also used extensively for building and infrastructure construction, and some specialized applications such as meteorology and rocket launching. It consists of a moveable telescope mounted so it can rotate around horizontal and vertical axes and provide angular readouts. These indicate the orientation of the telescope, and are used to relate the first point sighted through the telescope to subsequent sightings of other points from the same theodolite position. These angles can be measured with accuracies down to microradians or seconds of arc. From these readings a plan can be drawn, or objects can be positioned in accordance with an existing plan. The modern theodolite has evolved into what is known as a total station where angles and distances are measured electronically, and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transit (surveying)
A theodolite () is a precision optical instrument for measuring angles between designated visible points in the horizontal and vertical planes. The traditional use has been for land surveying, but it is also used extensively for building and infrastructure construction, and some specialized applications such as meteorology and rocket launching. It consists of a moveable telescope mounted so it can rotate around horizontal and vertical axes and provide angular readouts. These indicate the orientation of the telescope, and are used to relate the first point sighted through the telescope to subsequent sightings of other points from the same theodolite position. These angles can be measured with accuracies down to microradians or seconds of arc. From these readings a plan can be drawn, or objects can be positioned in accordance with an existing plan. The modern theodolite has evolved into what is known as a total station where angles and distances are measured electronically, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Milliradian
A milliradian ( SI-symbol mrad, sometimes also abbreviated mil) is an SI derived unit for angular measurement which is defined as a thousandth of a radian (0.001 radian). Milliradians are used in adjustment of firearm sights by adjusting the angle of the sight compared to the barrel (up, down, left, or right). Milliradians are also used for comparing shot groupings, or to compare the difficulty of hitting different sized shooting targets at different distances. When using a scope with both mrad adjustment and a reticle with mrad markings (called an "mrad/mrad scope"), the shooter can use the reticle as a ruler to count the number of mrads a shot was off-target, which directly translates to the sight adjustment needed to hit the target with a follow up shot. Optics with mrad markings in the reticle can also be used to make a range estimation of a known size target, or vice versa, to determine a target size if the distance is known, a practice called "milling". Milliradian ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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