TM 9-1290-357-15
two lines crossing each other at right angles,
and an adjustable objective with a diopter scale
and attached index. The eyepiece diopter scale
is graduated from + 4 to - 4 diopters and the ob-
jective scale is graduated from + to - 1 diopter.
The eyepiece scale is used in conjunction with
the objective scale to determine focus and paral-
lax readings of the aiming circle.
Figure 4-2. Dioptometer
that the objective can be accurately positioned,
setting the collimator at the parallax distance re-
quired for the aiming circle telescope. The scale
is graduated with an infinity mark, and four
other marks representing 500, 200, 100, and
75 yards.
4-8. Dioptometer
The dioptometer (fig. 4-2) is a small calibrated
collimating telescope. It contains a conventional-
type focusing eyepiece with an attached diopter-
scale, a stationary reticle pattern consisting of
