Sighting in the dark

     Interest in night vision gear and what it offers to law enforcement and civilian users has increased. The first Gulf War made most realize that night vision has revolutionized the modern battlefield and is a crucial advantage exploited by U.S. armed forces. As often happens with technology, this advantage is now becoming available to the law enforcement and civilian markets.

     San Francisco, California-based American Technologies Network Corp. (ATN) manufactures advanced night vision equipment in many versions or types of night vision devices across the different technological designations (Generation 1, 2, 3 and 4). Night vision weapon sights, goggles, binoculars, monoculars and day/night systems are all available from ATN. Thermal imaging equipment is also offered.

     The PS22-3a Night vision optic mount is a top-of-the-line Generation 3 device using handpicked image intensification tubes for the highest performance. Generation 3 devices are considered so technologically advanced that exporting such devices from the United States without a valid export permit issued by the U.S. State Department is strictly prohibited. The PS22-3a meets or exceeds military specifications with a resolution of 64 lp/mm to 72 lp/mm and signal to noise ratio (SNR) minimum of 20.

     Resolution is defined as the ability of a night vision system to distinguish between objects close together. Image intensifier resolution is measured in line pairs per millimeter (lp/mm). SNR is a measure of the light signal reaching the eye divided by the perceived noise as seen by the eye. A tube's SNR determines the low-light resolution of the image tube. A high SNR translates into the tube's better ability to resolve objects with good contrast under low-light conditions. Many experts in the field feel the SNR is the best indicator of an image intensifier's performance because SNR is directly related to the photocathode's sensitivity and accounts for phosphor efficiency and micro-channel plate (MCP) operating voltage.

     The PS22-3a is designed to mount in front of a day optic scope. The concept is based on wanting to give users the convenience of using their day optic at night without having to switch out aiming devices or having to dedicate a weapon solely for use at night. Any weapon can be adapted for night use as long as the PS22-3a can be placed in front of a suitable day optic device. The available choices for the day optic that are compatible to use with the PS22-3a are wide ranging. One important advantage of the PS22-3a concept is not requiring the optic to be sighted in every time it is employed, since the day optic never moves. The PS22-3a is attached or detached with no impact on the day optic's point of aim, and parallax is not an issue. Another benefit of the PS22-3a is that a scope's reticle does not need to be illuminated or IR-compatible for it to be visible when using the PS22-3a. This differs from night vision products that mount to the rear of the scope.

     Previous attempts to adapt a day optic for night use involved devices mounted behind the optic. This caused obvious eye relief issues unless the day optic was shifted forward, allowing for the night vision device and creating the need for the weapon system to be sighted in again or dedicated to night use — negating the convenience and familiarity of using one weapon system across multiple scenarios.

     Mounting an ATN night vision scope specifically designed for use in night operations, the Mars 6x-3 for example, avoids the hassle of the constant on/off procedure needed for designs not mounting in front of the day optic. If an aiming device is moved it needs to be sighted in again to guarantee accurate shot placement, especially if the weapon is intended for engagement ranges past 50 yards. The PS22-3a offers the versatility of allowing a law enforcement agency or civilian to take advantage of night vision technology without having to use limited resources on setting up a weapon solely for night time tasks.

     One component of the ATN PS22-3a is its adaptability. A plethora of mounting options are available, including a 7/8-inch weaver mount, ARMS quick-release adaptor, Picatinny rail and scope ring adaptor mount with different size inserts for the various scope objectives one may encounter. A platform ring is also available for using the ATN IR450 illuminator with the PS22-3a, if desired. Loosely speaking, the IR450 is an infrared "flashlight" that increases the available ambient light for the PS22-3a process, resulting in brighter images. This enables the passive Generation 3 PS22-3a to operate under the most adverse ambient light conditions, for example a cloudless moonless night in the middle of nowhere or the interior of a large factory or warehouse. Tactically, one must be cautious when using IR illuminators because anyone in the vicinity with night vision gear will be alerted to your position when used. This is probably not a huge consideration for the law enforcement or civilian user — at least not yet. The PS22-3a is right at home on any AR-style weapon platform equipped with full-length Picatinny rails. The PS22-3a was tested on various AR-15 models, combined with the Trijicon ACOG and Leupold Mk4 CQ/T optics. The PS22-3a used in conjunction with the Armalite AR-10A4 chambered in .308Win and Leupold Mk4 3.5-10x scope translates into a hard hitting weapon fully capable of taking advantage of the PS22-3a's viewing range.

     Using the PS22-3a with a bolt action rifle is a little more problematic due to the mounting requirements. The optional ATN scope ring adaptor is workable; however there are concerns over long-term durability and keeping it in place. The 14.5-ounce MIRS Scope Mount, from McCann Industries mounts simply and securely, is available for several different bolt-action rifle models, and gives the user the ultimate flexibility in mounting the PS22-3a, IR illuminators and tactical lights. The decision to use the McCann Industries' MIRS Scope Mount should be based on how often the PS22-3a will be used with a specific bolt-action rifle. The ATN scope mount adaptor will more than suffice if the bolt action is not the primary platform for the PS22-3a.

     The PS22-3a is better utilized on scopes with smaller objective lenses. A scope with an objective lens larger than 40mm decreases the PS22-3a's 13-degree field of view. This is due to the PS22-3a's 21 mm exit pupil. The optimum scope magnification range to use with PS22-3a is between 1x to 6x, with 2.5x to 4x being the sweet spot. ATN literature points to the Trijicon 4x20 ACOG and Leupold CQ/T as the ideal set-up with the PS22-3a, based on the exit pupil to objective lens considerations. Choosing a high magnification scope, a 6.5-20x50mm objective lens model for example, is counter-productive considering Generation 3 night vision devices have a listed detection range of approximately 350 yards, and a recognition range of 300 yards with both measurements highly dependent on ambient light conditions. I have found 300-yard detection and 220-yard recognition ranges are a more realistic expectation. These ranges do not require a high magnification scope for effective target engagement. This is supported by PS22-3a range testing.

     Buyers beware of claims from manufacturers stating figures that greatly exceed these for other Generation 3 devices. There is a subjective quality to what is meant by detection and recognition, not to mention ambient light conditions and object being viewed. ATN is expecting to release a PS22 model with a 40mm exit pupil later this year designed for use with scopes sporting 40mm to 60mm objective lenses.

     The PS22-3a can be utilized as a handheld Night vision device for general observation roles. This expands its possible uses in the law enforcement or civilian market. Its compact size, approximately 5-inches by 3-inches by 3-inches and weighing just more than 1 pound, allows for easy carrying and unobtrusive use compared to if it was mounted on a weapon and used for observation. The PS22-3aoffers a clearly marked off/on switch, easily adjustable focusing ring and accessible battery compartment for the CR123A battery. Battery life is rated at 50 hours of use. The PS22-3a's quick detach and attach method allow for easy use back and forth between handheld use and weapons mounted. More versatility is gained with PS22-3a adaptability for use with spotting scopes and cameras.

     Range testing took place on a variety of rifles ranging from AR-15, AR-10 and Savage FP10 bolt-action models with optics consisting of the Trijicon 4x20 ACOG, Leupold Mk4 CQ/T and Leupold Mk4 3x9, 3.5x10 and 4.5x14 scopes. The image quality was excellent with the optics' crystal clear day image qualities transformed into crisp green-tinted images by the PS22-3a.

     One observation is that the user should refrain from turning on any illuminated reticles too brightly, as this was found to wash out the green background. The normal black reticle on the Leupold CQ/T and Mark 4 scopes showed up fine against the bright green background.

     The PS22-3a proved easy to detach and mount between the different weapons and optics. The day optics' zeros were not effected out to a tested 250-yard range. The PS22-3a remained clear and with minimum "blooming," or random black spots, that night vision devices can experience. The automatic brightness control incorporated in the PS22-3a automatically adjusts the brightness of the image intensifier tube to the optimal setting, and shuts the unit down if unexpectedly exposed to a bright or intense light. This protects both the PS22-3a and the user from damage. This is especially important with an night vision unit used as an aiming device. The day optics' crosshairs or aiming point must remain undisturbed for accurate shot placement. The PS22-3a turns any day optic into a very capable medium range night weapon sight.

     Field of view was narrowed when utilizing the PS22-3a's as compared to the normal field of view inherent in the day optic. Ensure the person, officer or department trains in the use of the PS22-3a to become familiar with the night vision device.

     Generation 3 night vision gear is expensive so ATN often offers the same basic design across different technological generations. If the PS22-3a is the concept an individual or department wants but the price tag is prohibitive, a similar product is available in a Generation 2-type model, i.e. the PS22-2. This allows great flexibility in fitting needs into tight budget requirements. The forward-mounting ability is present with the PS22-2 at a reduced price compared to the Generation 3 PS22-3a, albeit with reduced viewing range capabilities. Unless one was previously exposed to Generation 3 night vision, the Generation 2 PS22-2's ability would surely dazzle its owner.

     ATN prides itself in not only servicing the military and law enforcement market, but also the civilian consumer, thus the justification for keeping a wide ranging product line available. The PS22-3a serves to maximize an individual or departments' night vision dollar.

     Todd Burgreen is a freelance writer with work published in a variety of firearms and weapons publications.