Night Vision - An Overview






Night Vision - An Overview



Contributed By: L. S. Barrel







Now that we're able to buy imported night vision epuipment at reasonable prices, it would be nice

to have a guide so that we don't buy too much or too little of the gear that we want. What follows

is a brief explanation of the gear and some of the differences between the U.S. and the Russian

equipment.



The earliest night vision gear was the Infrared (IR) Metascopes, as used during WWII and the

Korean conflicts. IR gear is considered to be an "ACTIVE" night vision system. This means that

to be of much use beyond 35 yards, you need an "active" light source, suh as a floodlight, that

emits light in the Infrared spectrum (not visible to the human eye). As a result of the light source

and its power pack, IR gear tends to be bulky. IR equipment is not generally affected by visible

light and within its range limitations of 200 - 300 yards, depending on the light source, it is an

excellent choice of night vision gear for an urban area.



CAUTION: An IR light source that you're using can tell an opponent where you are

located. It's like driving a car at night, using the headlights. Although the driver can only use the

lights to see 300 yards of the road, somebody else can see those lights up to two or more miles

away. Other IR equipment and most Starlight night vision equipment can spot IR light sources at

a distance... Maybe not well enough to identify you, but certainly well enough to determine your

approximate position.



Starlight night vision equipment was developed in an attempt to get away from the drawbacks of

the IR gear, with its bulk, weight, and the light source. The early Starlight gear was fielded during

the Vietnam conflict (ANPVS-2). Starlight works very much like your television, in that the actual

work is being done inside an image tube. Starlight vision equipment is considered to be a

"PASSIVE" night vision system, since it uses available light and requires no external light

source. The optical end of the Starlight scope transmits the available light to the image

intensifier tube, which then electronically amplifies the light and then sends the amplified light to

the viewing screen end of the tube that you're looking at. There are two drawbacks with this

system:



No light - No image

Too much light and the unit burns itself out



The explanation I have given of how the Starlight system works is a gross over-simplification of

what's going on. If you want the details, please consult you local rocket scientist.



Starlight gear can operate in the Infrared light spectrum as well as with ambient light. The early

Starlight gear (U.S.) operated by amplifying the light from 25,000X to 45,000X. The early, first

generation U.S. gear was designed for the boondocks and did not have circuitry to prevent an

overload of light from burning out the image tube, not to mention the user's eyeball. It was also

fairly bulky, compared to the later stuff, but generally had very good optics.



The later U.S., second generation Starlight gear (ANPVS-4), had improved the image tubes' light

amplification abilities to 50,000X to 80,000X and reduced the size of the scopes by using

catadioptic lenses, but the optical clarity suffered as the useable ranges increased and rendered

a very grainy picture as compared with the first generation. Also the later gear incorporated

Automatic Brightness Control (ABC) circuitry to prevent light overload damage from destroying

the image tubes and injuring the user.



Much of the earlier U.S. first generation Starlight gear was upgraded with ABC circuitry during

the rebuild process. The current U.S., third generation equipment is continuing the trend towards

smaller, lighter, and more robust designs, with even higher light amplification of 85,000X to

125,000X and beyond. Fortunately, the latest gear is also addressing the grainy image problem

as well by enhancing the optical portion of the scope within the size and weight limitations

(LITTON Industries M-856 scope).



WARNING: My comment about Starlight night vision gear being like your television set

was deadly serious. All televisions sold in the United States use leaded glass in their picture

tubes. This is to reduce your exposure to the Gamma and X-ray radiation generated by the

image tubes. All U.S. Government Issue Starlight gear uses leaded glass for the image tubes

AND all the optical lenses between the image tube and the user's eys. The imported gear many

or may not use leaded glass...I don't know. As it is highly unlikely that you would constantly use

Starlight night vision gear, the risks of exposure from the Imported gear can be minimized.

Now to address some of the problems you encounter when trying to shop for and compare the

various devices on the market:



There are no internationally recognized standards for measuring light amplification. The

U.S. military has their own standard and it isn't the same as the Russian standard.



When you start talking about the "generation" of the night vision gear, you'd better know

who's yardstick you're using.
















Type Of Vision Gear

Light Amplification

U.S. Time Frame

U.S. Generation Level

Russian Generation Level



Infrared

* See Note *

WW II & Korea

0

First



Early Starlight(ANPVS-2)

25,000X - 45,000X

Early Viet Nam

First

Second



Later Starlight(ANPVS - 4)

45,000X - 80,000X

Later Viet Nam

Second

Third



Current Starlight(Litton M-856)

80,000X - 125,000X

Desert Storm

Third

N/A









NOTE  The U.S. does not generally rate IR systems for light amplification, however the

Russian 1st generation equipment tends to be rated from 0X to 20,000X. Also, due to differences

in the measurement standards, the Russian light amplification tends to be lower than the U.S.

equipment of the same generation level. On the plus side, the optical clarity of the Russian gear

tends to be exceptional for the cost of the stuff.



As you've noticed from the above chart, the Russian night vision gear is always one number

higher that the equivalent in U.S. development terms. To the best of my knowledge, Russia has

no equivalent to the state-of-the-art U.S. 3rd generation night vision equipment.



NIGHT VISION GOGGLES:

If you're considering buying a pair, PLEASE talk to someone who used them in the military.

They're nice to have ... if you understand their drawbacks. For instance, you can only focus them

at one distance. If you've got them set for 50 yards, you probably won't even see the 4ä tree limb,

8â away ... that you're about ready to walk into.



THERMAL VISION EQUIPMENT: 

You've been watching too many movies, pal. Thermal identifies heat sources only, it won't tell

you much more than that. A 200 lb. bolder at 100¡ F in the early evening, looks the same as a

man, but by dawn, when the rock has cooled down to 70¼ F, it is a whole different thing. Thermal

gear at present is very bulky, extremely expensive, and mostly found on big weapons, like anti-

tank. The British made a design breakthrough about a decade ago, but it immediately was NATO

classified, so I don't think you'll be seeing it anytime soon on the commercial market.



I have specifically avoided mentioning any of the Russian made night vision equipment by name

or by model number since all of the importers are re-naming what they are bringing into the U.S.

Also, I have no way of knowing what is available in your area. Please get data sheets from the

sellers of the equipment so you can determine if the gear does what you want it to and see if it

falls within your budget.



Author's Note:  I happen to personally like a Russian Starlight weapon scope, called the

PON 3X78 WITH the IR illuminator. The useful range as a starlight scope is 500 meters. In the

total abscence of light, the IR illuminator will give a useful range of 75 meters. It uses Weaver

style scope mounts, which are the most common type in the U.S. It will run continuously on a set

of AA bateries for 15 hours. It is an excellent choice for an urban starlight scope and costs less

than $800.00







