NIGHT VISION IN VIETNAM

By James L. Ballou

It has always been the dream of man to have the ability to see in the dark as well as our feline friends. World War II saw the development of infrared technology resulting in the M3 sniper scope. Contrary to movies, the image was not red but green, as it appeared on a cathode ray tube.

There are two main groups of night vision devices, active and passive. An active device requires some sort of secondary, non-visible light source, such as infrared. A passive device magnifies the ambient or available light. An improvement of the television camera tube led to increased ambient light by thousands of times. These are the so-called “Starlight” scopes. The first and second-generation scopes had one problem, “blooming” or “fade-out”, when a major light source overwhelmed the device or even a flash from the muzzle would cause shut down. Third generation devices all but eliminated that problem.

The beginning of night vision can be traced to World War II. It was the invention of the Cathode ray tube for early television that made the technology possible. Both the Americans and Germans experimented with active devices, in the infrared spectrum.

The American M3 “sniper scope” (as seen in the lead photo) required a wet cell backpack of limited life. The scope could be taken off the M3 carbine and used just for observation, and it was then called a “snooper scope”. Its short battery life and fuzzy view doomed it to early failure, though some were used in the Korean War and to some extent Vietnam. In 1943 the Germans in developed the ZG 1229 known by the code name “Vampir” – a first generation active scope for the StGw 43. (See SAR Volume 3 Number 5 for a complete description of this system).

Vietnam Era: Passive Scopes

The Vietnam era scopes were the early passive scopes. The blooming problems and fade-outs made them somewhat unreliable for sniper use. The AN/PVS-2 was useless as a sighting device. The adjustments in the scope just would not hold a zero at any range, even with the best of rifles. They were, however, useful for observation and often used from towers to scrutinize enemy activity.

The rubber eyepiece has a device to open the aperture so you may view the scope. Obviously the light coming from the scope could give away one’s position. On the first generation scopes there was no such device. Special Forces personnel many times noted that the operators often had “Owl Eyes”, a greenish glow that emanated from the eyes during use.

One sometimes sees photos of a “starlight” scope mounted on an M2 HB .50 caliber Browning machine gun. This was not very practical as the recoil forces soon destroyed the device. Also, the first shot most often blotted out the orthicon tube.

The AN/PVS-2 starlight scope was, also know by the acronym STANO (Surveillance, Target Acquisition and Night Observation). It was developed by the US Army at the US Army Electronics Command with optical support of the Wollensack Optical Company, as its prime contractor. With a weight of 5.94 pounds it is rather ungainly on an M16 Rifle. It eliminated the cumbersome backpack battery, but in the humid conditions of South East Asia, battery integrity was a nagging problem. There was also a constant whining sound from the instrument that threatened to give away one’s position.

John “Gunny” Smith (Gunny ran security at the old North Country Shoot) was on the “Rock Pile” DMZ, when he encountered a first generation starlight scope mounted on an M14. It had been stabilized on a tripod in the bunker. He reported movement on the line, and was given the order to fire. He fired a burst at the movement but his contact, in reality, was of the Simian kind. He had eliminated a rather large indigenous Monkey!

Active Devices

There were some infrared, active devices used in Vietnam including the WWII Sniper scope on the M3 Carbine. There was one used on the M14, but it still required a battery pack, a six-pound, six-volt nickel cadmium battery.

There was also the metascope originally designed in World War II by the US Navy, which evolved into a transistorized hand held active device for viewing out to 50 meters. When you see the large 1000-watt searchlights on tanks, with the infrared filter, they would be used to illuminate the area to be seen through the metascope.

The Other Side

Though the VC and NVA “ruled the night”, they had very little in the field of night vision. The dreaded Dragunov Rifle sight (PSO-1) had one feature that few knew about. It did have an infrared detector sensitive to any active light source. The reticule was also illuminated in red in order to maintain visual purple integrity. This is the mechanism in your eye that allows you to see in low light. By no means was the sight capable for seeing any better in low light, but it was the best they had.

The use of the night vision devices in Vietnam was in the incipient stage. For the detection of enemy movement and disposition, it had its moments; but for target acquisition of individual soldiers, it was less than satisfactory. It was not until the Gulf War that man’s dream of seeing in the dark was fulfilled.