Ferranti Night Vision Goggles

 

 Night vision goggles are popularly used to improve viewing performances not only during night applications but also including rescue and retrieval operations. It is fundamentally an objective lens which centralizes the captivity of any images towards the photo-cathode of a picture intensifier tube. As an effect, it resulted to an enlarged image that is visualized through an eyepiece lens. There are several versions of night vision goggles in development and in use today. Some of which are AN/AVS-6, AN/PVS-5, Cat's Eyes, PVS-7, Nite-Op Ferranti night vision goggles, Merlin, Eagle Eyes, and a lot more.

 Some product models offer a short description and features in order for the end user to understand its applications and functions. There are some parameters utilized to distinguish the night vision goggles image capability and quality. These parameters include FOV or field-of-view, spectral sensitivity, resolution, distortion, brightness gain, optical axes alignment, magnification, overlap, image rotation, exit pupil diameter, beamsplitter ratio, eye relief, and etc.

 Generally, all night visions goggles are almost similar since they own all the three fundamental components: an image intensifier, an objective lens system, and an eye lens system. Nevertheless, there are several distinct methods wherein these various components can be created and engineered to establish the trade-off in the middle of several design boundaries. The image intensifier tube is the core of any night vision goggles. Ferranti night vision goggle tubes of both II and III generation are popularly utilized in fielded systems today to develop more quality night vision goggles suitable for any nocturnal purposes.

 The Gen II goggles that use image intensifier tubes are commonly known to as Gen II night vision goggles and are readily affected to light exposures from about 400 nm to about 900 nm. While on the contrary, the more responsive Gen III image intensifier tubes can be only affected from about 600 nm to a little over 900 nm light exposures. This can be base to a human visual spectral sensitivity that comes from about 400 nm to 700 nm. The Gen III tubes are almost 4 to 5 times more responsive to night sky intensification compared to the Gen II image intensifier tubes but they are almost expensive.

 NITE-OP NVGS is one example of Ferranti night vision goggles designed by Ferranti International for the British military as an enhancement over the ANVIS night vision goggles. The fundamental design is very likely to the ANVIS night vision goggles but the mounting system is much craggier and the field of view is wider. Further, lenses for the eyepiece are much wider in terms of diameter, which allows maximum eye comfort and larger positioning or mounting tolerance with regards to the user’s eyes.  45 degrees circular FOV, 20/40 - 20/50 Snellen resolutions, no exit pupil, no beamsplitter, -3.5 to +0.5 diopters eye lens adjustment and weighing 750 gm are summary of its key characteristics.