Figure 8-22. Battery commander's periscope - assembled view, reticle pattern.

TM 9-258

b. The BC periscope employs 90ƒ prisms at the

elevation and azimuth. One lamp provides illumination

for the reticle. Another lamp, on a flexible cable, is used

top with their mates at the bottom to complete a Porro

as a hand light to read the instrument scales and

prism erecting system (para 4-5c) (thus eliminating the

lens erecting system) and also to effect a vertical

d. Each periscope is provided with filters;

displacement of the line of sight.

c. The instrument has a magnification of 10

amber, red, neutral (smoke), or a clear window may be

moved into position between the objective lens and

power and a field of view of 60. It is used for observation

eyepiece of either telescope.

and for measuring angles. The right telescope contains

a reticle, calibrated in mils (1/6400 part of a circle), for

measuring

angles

Section VII. RANGE FINDERS

8-21.

General.

angle of convergence is indicative of the range. The

a. The range finder is essentially two periscopic

compensator lenses (27 and 28, fig 8-23) provide

telescopes or sights (either with one eyepiece or two)

angular deviation of the right line of sight for ranging.

with two lines of sight through prisms or reflectors at

ends

converging

the

target.

The

8-19