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Reticle

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A reticle, also known as a reticule or a graticule, is a pattern of fine lines or markings placed within an optical device.

Reticles vector
Reticles vector

These patterns are built into the eyepiece of instruments like telescopic sights, microscopes, and theodolites. They provide essential measurement references during visual inspections. By using these markings, observers can perform precise calibrations or measurements. While the term "reticle" is most common for weapon sights, "graticule" is often used for scientific instruments like oscilloscopes or astronomical telescopes. The word itself comes from the Latin reticulum, which means a small net.

The most fundamental type of reticle is the crosshair. This pattern consists of two lines that intersect perpendicularly to form a cross shape.

PocketComparator2
PocketComparator2

However, designers use many variations to suit different needs. These can include dots, posts, concentric circles, chevrons, or graduated markings. For precision aiming, thin lines are often preferred. Yet, thin lines can be lost against complex or busy backgrounds. To solve this, many modern scopes use a duplex reticle. In a duplex design, the bars are thick on the perimeter and thin out in the center. The thick bars help the eye locate the center quickly, while the thin center lines allow for extreme precision.

Reticles are constructed using several different methods. In the past, makers used incredibly thin and strong materials like hair or spiderweb. Specifically, silk from the cocoon of a brown recluse spider was used for its strength and fineness.

ПД-8 (ПД-8А)
ПД-8 (ПД-8А)

Modern versions often use wire crosshairs that can be flattened to change their width. These wires are usually silver but appear black when backlit. Another method is the etched glass reticle. This technique was first suggested by Philippe de La Hire in 1700. It involves engraving lines onto a thin glass plate using a diamond point. Etched glass allows for complex shapes, such as floating elements or circles, that do not cross the entire field of view.

Some reticles are designed to be illuminated for use in dark conditions. This can be done using a plastic or fiber optic light pipe to collect ambient light. Alternatively, a battery-powered LED can provide light. Some specialized sights use the radioactive decay of tritium for illumination. This allows the sight to work for 11 years without a battery.

USGsight01
USGsight01

Red is the most common color for illumination because it is the least destructive to night vision. However, some users choose green or yellow. Some modern systems even use a digital image superimposed on a screen to create the reticle pattern.

In telescopic sights, the location of the reticle matters. It can be placed at the first focal plane (FFP) or the second focal plane (SFP). In a variable power sight, an FFP reticle stays the same size relative to the target as you change magnification. In contrast, an SFP reticle stays the same size relative to the user's eye. While FFP reticles are slightly more durable, many American users prefer the SFP design. This allows the reticle to remain a constant size even as the target image grows or shrinks.

Specialized optical systems use collimated reticles. These are produced by non-magnifying devices like reflex sights or red dot sights.

Reflector reflex sight diagram 3
Reflector reflex sight diagram 3

A collimated reticle is an image superimposed over the field of view. Holographic weapon sights take this a step further. They use a collimated laser diode to build a holographic image of a reticle at a finite range. This eliminates certain parallax problems found in standard red dot sights. While holographic sights can be heavier and use more battery, they allow for almost any shape or size.

Reticles play a massive role in various scientific and professional fields. In astronomy, a filar micrometer can be used as a reticle to measure angular distances between stars.

Pso-1onsvd
Pso-1onsvd

Surveyors use specialized reticles in levels and theodolites to take distance measurements using stadia marks. Some reticles are even designed to help shooters calculate range. For example, a 30/30 reticle has thin bars spanning 30 minutes of arc. This is roughly equal to 30 inches at 100 yards. This allows a person to deduce the range of an object based on its known size. The importance of these tools is even recognized in the stars, as the constellation Reticulum was named to honor the reticle's contribution to astronomy.

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🖼️ Images & Media (8)
File:Pso-1onsvd.jpg
Pso-1onsvd.jpg
File:Reticles vector.svg
Reticles vector.svg
File:20090906 022641 Algae.jpg
20090906 022641 Algae.jpg
File:PocketComparator2.JPG
PocketComparator2.JPG
File:ПД-8 (ПД-8А).jpg
ПД-8 (ПД-8А).jpg
File:Findot reticle.svg
Findot reticle.svg
File:USGsight01.jpg
USGsight01.jpg
File:Reflector reflex sight diagram 3.png
Reflector reflex sight diagram 3.png
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