Reticles.

TM 9-258

plate as in a reflex system.

4-9. Reticles.

(1) Crosswires (A, fig 4-24), commonly used in

a. The majority of reticles (para 5-19) are glass

rifle scopes, give increased light transmission by

disks with plane parallel surfaces. Appropriate markings

eliminating one piece of glass. With a wire reticle, there

are engraved or etched on one of the surfaces. In some

is no glass surface present to become dirty and require

cases, a planoconvex lens is required at the point where

cleaning. Crosswires may be cleaned with little effort by

the reticle would be mounted. In such cases, the

using a camels-hair brush dipped in carbon tetrachloride.

markings are engraved on the plane surface of the lens.

A dirty glass surface in the image or reticle plane is in

b. Military reticles are of several types: wire (or

sharp focus and under magnification. Such a glass

some filament material), a post (picket), an etching on a

reticle surface, therefore, must be clean.

plate glass or lens surface, or a punched metal

Figure 4-24. Representative types of reticles

(2) Reticles on glass commonly are used in

Glass provides a surface for any desired reticle design or

most military sights. The reticle pattern is etched and

pattern as illustrated in B, C, and D, figure 4-24. This

filled on a planoparallel plate so that it is seen as a black

glass surface must be perfectly clean as it is in a focal

silhouette. If illuminated, it will glow with reflected light.

place and all dirt is in perfect focus and magnified. A

4-26