Operation

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