Signalman 1 & C - Historic Naval Ships Association

You were born with the finest optical equipmentyou will ever use—your eyes. But even if you have20-20 vision, it often is impossible to read flaghoistand other signals accurately with the naked eye. Tomagnify distant signals, some of the following aids tovision are carried aboard Navy ships.SHIP'S BINOCULARSShip's binoculars (known as big eyes) have amagnification of 20-power, with an apparent field ofview of approximately 70 degrees. The binoculars aremounted on a height-adjustable carriage assembly thatis adjustable through 70 degrees elevation rangingfrom 10 degrees depression to 60 degrees elevationwith reference to the horizon, and that can rotatethrough 360 degrees in azimuth. Ship's binocularsconsist of the binocular assembly, carriage assembly,and the pedestal (fig. 2-13).The binocular assembly contains the opticsrequired to obtain the desired magnification.Eyeguards are provided to keep stray light from theobserver's eye when sighting through the eyepiece.The focusing knob enables the eyepiece to beindividually adjusted. Each focusing knob is providedwith a diopter scale, which is graduated from -3 to +lin 1/2-diopter increments. The interpupillary distance(IPD) of the eyepieces is controlled by an interocularhandle, and is adjustable from 56 to 74 millimeters.An INCREASE-DENSITY control is provided toadjust the polarized light filter. Inlet and outlet valves,located on top of the main housing assembly, areprovided to evacuate and recharge the binocularassembly with dry nitrogen.The carriage assembly enables the binocularassembly to be positioned in the proper azimuth andelevation. The carriage assembly contains a360-degree azimuth scale graduated in l-degreeincrements. The binoculars may be locked in anyposition from minus 10 degrees to plus 60 degrees bythe elevation or azimuth knobs. The carriage alsocontains a handcrank that allows vertical adjustmentof the binocular assembly through a range of 8 inches.The pedestal assembly is used to mount thebinoculars to the deckOperationFigure 2-13.—Ship's binoculars.Perform the following procedures to operate theship’s binoculars (fig. 2-14):1. Using the elevation handle, crank the binocularassembly to the desired height.2. Loosen the headrest assembly knob and adjustthe headrest to obtain proper relief and to center youreyes before the eyepieces. Tighten in position.3. Adjust the interocular adjust knob until the samefield is visible in both eyepieces.4. Loosen the azimuth carriage and binocularelevation lock knobs; using the control handles,maneuver the binoculars in either azimuth or elevationso that the rear sight and front pin are trained on theobject.5. Rotate the variable-density control knob toremove the density filter from the optical path.6. Individually move an eyepiece to the extremeplus diopter setting. Place your eyes into position andslowly move the eyepiece in until the image of the targetis clearly defined. If the eyepiece is allowed to go pastsharp definition, do not refocus; start over. Memorizeyour diopter scale readings. These readings can be usedto make future focusing adjustments.2-11