You were born with the finest optical equipment
you will ever use—your eyes. But even if you have
20-20 vision, it often is impossible to read flaghoist
and other signals accurately with the naked eye. To
magnify distant signals, some of the following aids to
vision are carried aboard Navy ships.
SHIP'S BINOCULARS
Ship's binoculars (known as big eyes) have a
magnification of 20-power, with an apparent field of
view of approximately 70 degrees. The binoculars are
mounted on a height-adjustable carriage assembly that
is adjustable through 70 degrees elevation ranging
from 10 degrees depression to 60 degrees elevation
with reference to the horizon, and that can rotate
through 360 degrees in azimuth. Ship's binoculars
consist of the binocular assembly, carriage assembly,
and the pedestal (fig. 2-13).
The binocular assembly contains the optics
required to obtain the desired magnification.
Eyeguards are provided to keep stray light from the
observer's eye when sighting through the eyepiece.
Figure 2-13.—Ship's binoculars.
The focusing knob enables the eyepiece to be
individually adjusted. Each focusing knob is provided
with a diopter scale, which is graduated from -3 to +l
in 1/2-diopter increments. The interpupillary distance
(IPD) of the eyepieces is controlled by an interocular
handle, and is adjustable from 56 to 74 millimeters.
An INCREASE-DENSITY control is provided to
adjust the polarized light filter. Inlet and outlet valves,
located on top of the main housing assembly, are
provided to evacuate and recharge the binocular
assembly with dry nitrogen.
The carriage assembly enables the binocular
assembly to be positioned in the proper azimuth and
elevation. The carriage assembly contains a
360-degree azimuth scale graduated in l-degree
increments. The binoculars may be locked in any
position from minus 10 degrees to plus 60 degrees by
the elevation or azimuth knobs. The carriage also
contains a handcrank that allows vertical adjustment
of the binocular assembly through a range of 8 inches.
The pedestal assembly is used to mount the
binoculars to the deck
Operation
Perform the following procedures to operate the
ship’s binoculars (fig. 2-14):
1. Using the elevation handle, crank the binocular
assembly to the desired height.
2. Loosen the headrest assembly knob and adjust
the headrest to obtain proper relief and to center your
eyes before the eyepieces. Tighten in position.
3. Adjust the interocular adjust knob until the same
field is visible in both eyepieces.
4. Loosen the azimuth carriage and binocular
elevation lock knobs; using the control handles,
maneuver the binoculars in either azimuth or elevation
so that the rear sight and front pin are trained on the
object.
5. Rotate the variable-density control knob to
remove the density filter from the optical path.
6. Individually move an eyepiece to the extreme
plus diopter setting. Place your eyes into position and
slowly move the eyepiece in until the image of the target
is clearly defined. If the eyepiece is allowed to go past
sharp definition, do not refocus; start over. Memorize
your diopter scale readings. These readings can be used
to make future focusing adjustments.
2-11
