Copyright 2007. All rights reserved. Utah Gun Collectors Association.

“Fight at Night!”
U.S. Army Night Vision, 1945-1980

Darkness ended each day’s battle for centuries. 
An army able to see at night has a tremendous tactical advantage over an enemy enveloped in darkness.

From the collection of John S., displayed at the October, 2006 Utah Gun Collectors Association Gun Show.


First, we must review five very important terms:

1. Active vs. Passive night vision-

2. Visible Light vs. Invisible Light

 

Invisible
Light


Visible Light

 

Invisible
Light

 

Ultraviolet

 

Infrared

 

3. Active systems using visible light

Night time combat was sometimes possible with primitive torches, oil lamps, and later electric lighting from flashlights or searchlights to illuminate small areas.  But this made any activity visible to both friend and foe. 
Starting in World War I, battlefield illumination could be provided for limited times with parachute flares fired from artillery (such as those shown here), or dropped from aircraft.   These could illuminate large areas for a minute or two before the flares descended or burned out, again leaving darkness.  These are examples of “active” systems to provide artificial light that is visible to friend and foe alike.

4. Active systems using invisible light

In the 1930s, scientists developed electronic devices to detect invisible infrared light and convert it into a visible image.  They also developed a special filter that could be placed over a standard light source (such as a spotlight) so that only the invisible infrared light would come through the filter to light up a target.  If you had an infrared telescope, you could see objects illuminated by the infrared light source.  Of course, if the enemy had an infrared scope, they could see your light source, without giving away their own position.  The U.S. Army’s first successful units, like the one shown here were used in Okinawa in April, 1945. Later types used in Korea, and into the mid-1960s are also shown here.  Typical range of an infrared light source for a rifle is only 100-150 yards. The scope will show a dimly visible image like a small black and green TV image.

5. Passive systems using “starlight” scopes

By the 1960s, scientists had developed “image intensifiers” that could detect objects using ambient reflected light, such as moonlight, starlight, or skyglow.   The light is intensified up to 30,000 times in the scope so that objects become clearly visible. There is no need to have a light source, making the unit smaller and lighter, and there is no light source for the enemy to detect.  Effective range is about the same as with conventional sights, compared to only about 100-200 yards for an active infrared system. Three different types of passive starlight scopes for small arms used in Vietnam are shown here.  Because of the way the scopes operate, the images tended to blur and “ghost” if the scope was moved.  Greatly improved units (not shown here) are in use today.

 


U.S. Army Night Vision Systems 1945-1980


Active Illumination sources: Mortar Illuminating rounds

60mm mortar Illuminating round M83A3-  This will eject a flare that provides 250,000 candle power of illumination for a minimum of 32 seconds.  The parachute slows its descent to 10 feet per second.  Range is about 1,100 years (about 2/3 of a mile).

81mm mortar Illuminating round M301A2-  This has a flare that provides 500,000 candle power of illumination for a minimum of 60 seconds.  The parachute slows its descent to 18 feet per second.  Range is about 2,300 years (about 1.3 miles).

4.2 inch (107mm) mortar Illuminating round M335A2-  This will eject a flare with a 70 inch diameter parachute that will provide 850,000 candle power of illumination for a minimum of 90 seconds.  It can be fired up to about 5,700 years (about 3 miles).



Snooperscope Infrared, M2 on T3 carbine (circa 1945)


Type:  Active Infrared light source and viewing telescope
Weight: 5.7 pounds (telescope, light source and handle) 21.3 pounds complete with battery and power supply
Effective range: about 100-125 yards

Based on scientific experiments begun in the 1930s, the “Sniperscope, T120” was developed in late 1943.  Electronic devices could distinguish objects illuminated by infrared light and make them visible in a telescope.  A 6 volt light with an infrared filter mounted under the stock provided invisible light to illuminate an area up to about 400 feet away.  This combination of a light source and telescope using infrared light became the first practical night vision sight.  A handle and a switch for the light was mounted on the stock.  Both the telescope and the light source got their power from a heavy lead-acid wet cell battery carried in a canvas pack.

In 1944 a slightly modified version was designated the “Snooperscope, M1” and in 1945 additional small changes were made, resulting in the “Sniperscope, M2”. 

While the night vision telescope was being developed, the Ordnance Department was working on adapting the M1 Carbine to use a telescope of some sort.  In March, 1944, the T3 Carbine was approved for production.  This has a specially made receiver with integral mounts for attaching a scope with Redfield Junior style rings.  Only about 811 of the T3 carbines were made by Inland Division of General Motors, and 1,108 by Winchester (compared to over six million standard M1 carbines!). 

About 1,700 of the early (T-120, M1 or M2) Sniperscopes were made during WW2, and about 3,000 more after the war.  All were classified as “SECRET” at the time, and nearly all were destroyed, along with most of the T3 Carbines.  Perhaps a few dozen survive.

About 150 of the T3 Carbines and early Infrared Sniperscopes reached the field in time for the Okinawa campaign (April through June, 1945).  Reportedly they were effective in stopping night time infiltration into U.S. lines by the Japanese.



Sniperscope, Infrared, 20,000 volt Set No 1 on M3 Carbine  (circa 1950-1960)



Type:  Active Infrared light source and viewing telescope
Weight: 7.2 pounds (telescope, light source and handle) 28 pounds complete with battery and power supply
Effective range: about 135 yards

Mass production of a greatly improved infrared night vision system began in 1950 with the “20,000 volt Set No. 1”. This could be mounted on any M1 or M2 carbine, making it a “M3 Carbine.”  About 20,000 of these scope sets were made in 1950-1951, and they were used during the Korean War and remained in inventory until the mid-1960s.

The improvements in this system included better electronics, resulting in better vision, but still limited to about 135 yards.  Heavy weight and short battery life remained major shortcomings.  Moving the light source to the top of the scope instead of below the stock provided better illumination of the target and allowed shooting from the prone position.

While the Corps of Engineers worked on the night vision sights, the Ordnance Department worked on the M3 Carbine.  Instead of the T-3 carbine with numerous unique parts, they decided that a standard M1 or M2 carbine could be converted to use night vision sights using simple conversion kits in the field.  These special parts would be included with the sight sets.  The regular rear sight was removed from the carbine, and a clamp block attached to the barrel with a lug sticking up through a hole in the handguard.  A long bar installed between the rear sight dovetail and the barrel block provided attaching points for the Redfield style mounts for the sniperscope.  A handle was attached to the front of the carbine to control the light source.  A flashhider was added to conceal the user’s position.  When a standard M1 or M2 carbine had these modified parts installed, the designation became “Carbine, Caliber .30, M3.”

Many of the “20,000 volt Set No. 1” sniperscopes were sold off as surplus in the 1960s, with the power supplies rebuilt to use commercial batteries, and marketed to hunters and bird watchers. 



Sniperscope, Infrared, 20,000 volt Set No 1 for hand held observation (circa 1950-1960)



Type:  Active Infrared light source and viewing telescope

Weight: 7.2 pounds (telescope, light source and handle) 28 pounds complete with battery and power supply
Effective range: about 135 yards

The “sniperscope” used on the M3 Carbine could be mounted on a handle instead for use as a hand held observation  This eliminated the weight of the carbine, but also preventing shooting if the enemy was detected. 



AN/PAS-4 Weaponsight, Infrared Telescope Assembly used on M14 Rifle (circa 1962-1970)



Type:  Active Infrared light source and viewing telescope

Weight: 28 pounds complete with battery
Effective range: about 150-200 yards

As the M14 rifle was being developed to replace the M1 Garand and the M1 Carbines, work was also underway on a night vision sight better than the Korean War era units used on the M3 Carbine.  The resulting AN/PAS 4 used an active infrared light source and an electronic telescope to detect and convert the infrared image into a visible image.  However, the unit was still very heavy, but more reliable, and had a greater effective range.  It could be mounted quickly on any standard M14 rifle with no modifications required.  While the use of an active light source made use on the battlefield a risky job, it did provide the ability to fight at night.
About 4,000 of these sights were made in 1962, the last of the active infrared systems.  Within a few years they were made obsolete by the passive “Starlight” scopes.  Despite the relatively large number made, few of the AN/PAS-4 scopes are found in collections.



AN/PVS-1 Night Vision Sight “Starlight Scope” (1st Generation) used on M14 Rifle (circa 1965-70)



Type:  Passive “starlight” scope intensifying ambient light

Weight: [estimated] 8 pounds complete with battery
Effective range: same as with conventional sights

Scientific development started on these “passive” systems in 1961, and by 1965 the first primitive “starlight scopes” reached the field.  As a passive sight with no need to use an infrared light source the enemy was unaware of U.S. troops presence until they were fired upon.  No light source was needed, only the ambient light from the moon, stars or skyglow.

It could be mounted quickly on any standard M14 rifle with no modifications required.
Although a major breakthrough in technology, continued work to reduce weight and improve performance and reliability resulted in replacement by newer models within a few years. 



AN/PVS-2 Night Vision Sight “Starlight Scope” (1st Generation) used on M14 Rifle (circa 1967-75)



Type:  Passive “starlight” scope intensifying ambient light

Weight: 6 pounds complete with battery
Effective range: same as with conventional sights

Development started in 1964 and by 1967 these were reaching units in the field, and by 1969 they were very widely used in Vietnam.  Improvements included elimination of “blooming” where a bright light would temporarily “white out” the scope.  Battery life increased to about 100 hours.  It could be mounted quickly on any standard M14 or M16 rifle with no modifications required.



AN/PVS-3A Night Vision Sight “miniscope- Starlight Scope” (2nd Generation) used on M16 Rifle (circa 1970-1980)



Type:  Passive “starlight” scope intensifying ambient light

Weight: 3 pounds complete with battery
Effective range: same as with conventional sight

The “second generation” units used improved technology for greater light amplification for better performance with less ambient light.  Further weight reduction, and improved reliability and reduced cost made these very widely used in the closing months of the Vietnam War and afterwards.  It could be mounted quickly on any standard M16 rifle with no modifications required.


Copyright 2007. All rights reserved. Utah Gun Collectors Association.