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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 ...
arcminutes. 54 / 5 π ≈ 3.4377′. 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 ...
Reticle accessory (PD-8) used in sniper rifles. A reticle, or reticule[1][2] also known as a graticule, is a pattern of fine lines or markings built into the eyepiece of an optical device such as a telescopic sight, spotting scope, theodolite, optical microscope or the screen of an oscilloscope, to provide measurement references during visual ...
The PSO-1 pattern range-finding reticle. The bottom-left corner can be used to determine the distance from a 1.7 m tall target A 1.7 m tall person correctly ranged at 400 metres (437 yd) The PSO-1 features a reticle with "floating" elements designed for use in range estimation and bullet drop and drift compensation (see external ballistics).
External ballistics. This schlieren image of a bullet travelling in free-flight demonstrates the air-pressure dynamics surrounding the bullet. External ballistics or exterior ballistics is the part of ballistics that deals with the behavior of a projectile in flight. The projectile may be powered or un-powered, guided or unguided, spin or fin ...
A telescopic sight, commonly called a scope informally, is an optical sighting device based on a refracting telescope. [1] It is equipped with some form of a referencing pattern – known as a reticle – mounted in a focally appropriate position in its optical system to provide an accurate point of aim.
The Pentax 645 is a medium format single-lens reflex system camera manufactured by Pentax. It was introduced in 1984, along with a complementary line of lenses . It captures images nominally 6 cm × 4.5 cm on 120 , 220, and 70 mm film, though the actual size of the images is 56 mm × 41.5 mm.
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 distance from the telescope to the rod. This ratio is known as the stadia constant or stadia interval factor. Thus the formula for distance is. where.