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NIGHT OWL PAGE 1
SPOTTING SCOPES
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NIGHT OWL PAGE 2
Cobra Night Vision Frequently Asked Questions


1. How does night vision technology work?

Night Vision scopes and binoculars are electro-optical devices that intensify (or amplify) existing light instead of relying on a light source of their own. The devices are sensitive to a broad spectrum of light, from visible through infrared. An accessory illuminator can increase the light available at the infrared end of the spectrum by casting a beam of light that is not visible to the human eye.

You do not look "through" a Night Vision product, you look at the amplified electronic image on a phosphor screen.

Light enters the Night Vision product through an objective lens and strikes a photo cathode that has a high-energy charge from the power supply. The energy charge accelerates across a vacuum inside the intensifier and strikes a phosphor screen (like a TV screen) where the image is focused. The eyepiece magnifies the image.

2. Why are the projected images always green using night vision technology?

A Night Vision phosphor screen is purposefully colored green because the human eye can differentiate more shades of green than other phosphor colors.

3. What is the main difference between Russian made and US made Night Vision Equipment?



The large majority of Gen. 1 and Gen. 1+ night vision products sold in the US are of Russian origin, packaged and branded locally, usually by large optical manufacturers. The United States produces primarily Gen 2 and Gen 3 night vision technology, which is employed by and large by the military and other governmental organizations, and far out of the reach of most consumersí budget. Russia is the largest producer of Gen 1 and Gen 1+ image intensifiers in the world. Russian made night vision equipment, which also owes its origins to the Defense Industry, has always enjoyed a reputation of being among the best quality in the world.

4. What is the effective viewing range of a Night Vision Device?

It varies anywhere from 30 to 300 meters [900 feet]. The maximum viewing distance depends on the conditions of use. Overcast conditions, fog, rain etc. may reduce the effective distance of a night vision viewer. An Infrared illuminator will increase your viewing range, especially in enclosed spaces like a warehouse, garage or other enclosed parameters.

5. Can I use a Night Vision device in extremely low light, or absolutely no light conditions?

Yes. While it is true that your Night Vision device needs some available light to work, it is still possible to see a bright image in low light or no light conditions with the use of an Infrared Illuminator, which can be either built-in or attached to the device. On most of our products, the Infrared Illuminator is either standard, or available as an option.

6. Which Night Vision  product would you recommend for a first-time leisure user?

Either the Ghost with detachable IR or the Spirit.

7. What type of light source can be harmful to a Night Vision Device?

Your night vision device is designed to be used to assist your viewing in the dark. It may be harmful and will likely damage the device if you use it during the daytime or whenever there is sufficient light to see the object. Also keep in mind that strong direct light, such as projectors, car headlamps, strong flashlights and so on, may be harmful to your night vision unit if you direct you device at the source of these intense lights.

8. Can a Night Vision device and/or Infrared Illuminator be harmful to an individual?

All our Night Vision Optics products comply with FDA and international regulations in terms of safety for an electronic device, similar to other electronic devices such as televisions, and radios. Individuals with sensitive eyes such as those who experience eye fatigue while watching television, may experience the same sort of fatigue if they use their night vision viewer for a prolonged time.

9. Are Night Vision products waterproof?

In general no. Exposure to water and other liquids and even high humidity may damage night vision devices that are not specifically protected against these elements.  All our models are weather resistant, which means they can withstand short exposure to light rain or high humidity conditions.

10. Do you ship internationally?

We ship to a number of international locations, inclusive of Canada, Western Europe, Australia and New Zealand, Japan, Hong Kong and other countries.

11. What type of batteries do Night Vision Optics devices use, and how long will they last?

Night Vision  devices use commonly available batteries, such as 1,5V AA type, 9Volt square type, or 3V Lithium type. Generally the device will last up to 20-40 hours of continuous use if the Infrared Illuminator is in OFF position. If used with the IR Illuminator, expect 30-40% less operating time.

12. Does a high magnification device lend itself to better night vision viewing?

Not always. While a high magnification device in a lot of cases will increase the viewing distance, image gain and resolution are key factors to quality viewing. If a night vision binocular has a high magnification, of 7 times for example, but a low resolution and image gain, then the object viewed from a far off distance will be cloudy and dark. It is best to choose a night vision device with a good combination of high image gain, high resolution [23 lin./mm and up] and good magnification [2.0 or better].

13. What is the warranty-coverage on Night Vision products?

Every Night Vision Optics Dot Com device comes with a 12-month warranty on parts and labor. For additional questions, consult your owner's manual.

14. Is it really safe to purchase online using my credit card?

Yes. Our secure server software (SSL) is the industry standard and the best software available today for secure e-commerce transactions. It encrypts all of your personal information, including credit card number, name, and address, so that it cannot be read as the information travels over the Internet.

How Night Vision Works

People have numerous requirements to be able to see at night, and powerful illumination systems have been available since the first lighthouse went into service at Eddystone Rock, near Plymouth, Devon in November 1698. However, the drawback with all systems, until just prior to the Second World War, was that they were simply methods of illumination, with the obvious, and frequently very dangerous drawback, that everyone could see the source and origin of the light. For this reason it became imperative during World War ll that a solution be found for battlefield use, if a decisive advantage was to be achieved by one side gaining the ability to operate at night.

This breakthrough came about in 1936, when the first active Infra Red system was developed using a silver photocathode. These systems were very bulky and extremely primitive by todayís standards, but at the time, they represented a major military advantage. Active infrared systems continued in use until the late 1970ís in some countries, but NATO forces were phasing them out by the late 1960ís to be replaced by image intensifiers. The main drawback of Active Infra Red systems was that to operate they required powerful Infra Red Lamps, which meant that the range was restricted by the performance of the lamp. In addition, although Infra Red light is not visible to the naked eye (other than a very dull red glow if you are close to the lamp), a major problem could arise during military use should both sides utilize Active Infra Red systems, in that each side can see the light emitted by the others Infra Red Lamp. Hence, you are back to square one. With the source of the light easily identifiable the system is rendered virtually useless, and probably lethal, as you would only have to shoot at the lamp to take out the person holding it. It was at this point that new technology was urgently required, and Image Intensifiers or Starlight Scopes were developed.

The advantage of these systems was that Infra Red Lamps were no longer required, and for this reason they are referred to as Passive Night Vision devices. The principle of operation, is that they pick up whatever ambient light is available from the moon and stars, and amplify it so that the signal is strong enough to energize a sensitive screen. In the case of the earlier systems known as First Generation, or GEN1 (large numbers of which are still manufactured today), the principle of operation involved a light amplifier consisting of three elements enclosed in a vacuum tube.

The elements are: 1. The Photocathode 2. A Microchannel Plate 3. A Phosphor screen.

The photocathode receives particles of light, known as photons, through the front lens of the device which it then converts into electrons.

The microchannel plate consists of a cluster of Micro Channels. The actual number of microchannels varies, but runs into several millions, and are sometimes referred to as Rods. As the electrons travel through the plate, bouncing several times against the walls of the channel, they are accelerated and more electrons are created. This means that if one electron enters the plate, thousands will exit the channel and hit the phosphor screen, they then exit the screen as photons producing the green image, familiar to all night vision equipment users, which is visible through the eyepiece.

It is this process which brings us to the important subject that divides the good units from the bad, and that is the degree of Gain provided by the tube. Although the following explanation is simplified to avoid baffling you with unnecessary technical details, we hope that it will help you to understand the difficulties encountered by the manufacturers of the tubes. These problems centre not just on the continual need for development to increase the gain, but also on image definition, which, to a great extent depends on the number of channels that can be packed into the Microchannel Plate. It is for this reason that the manufacturers produce several types of microchannel plate, the main two being 18mm & 25mm, with the 25mm plate being capable of carrying considerably more channels. The main difference between Generation II and Generation III systems, (we will cover GEN. II + later) lies in the tubes, and the front end or third element, the Photocathode. It is this component that determines how many of the photons will be converted into electrons. In the systems employing the very latest technology (GEN.III), sodium potassium cesium antimonide (tri-alkali), is replaced by gallium arsenide, which is sensitive to infrared radiation (with wavelengths of up to 9 microns). In addition, it is important to bear in mind that with all night vision systems, each electron impact in the microchannels, generates gas ions which move back to the photocathode and impair its efficiency. However, in the case of GEN. III systems, the gallium arsenide photocathode can sustain the loss resulting from the build up of an ion barrier film. The less advanced GEN. II systems, using sodium potassium cesium antimonide tubes (tri-alkali), cannot deal with this build up and the performance is impaired.

SECOND GENERATION PLUS (GEN. II+).

Second Generation Plus is an enhanced version of the earlier second Generation devices, but capable of operating further into the infrared spectrum than GEN.II. However, as the designation implies, it is less sophisticated than GEN. III, in that it evolved just prior to the change from Tri-alkali tubes to gallium arsenide, which took place with the development of Third Generation technology. GEN.II+ does offer a useful performance increase over GEN. II systems, but is becoming less common since the development of third generation equipment. The reason being, that in terms of price, they are not much cheaper than third generation alternatives, but still suffer with most of the drawbacks of the older technology.

IMAGE INTENSIFIERS AND INFRA RED LAMPS.

Although image intensifiers, regardless of generation, all utilize available light, they cannot see in certain situations. The following are just a few examples: in shadow, underneath leaf covered trees, in barns and out buildings, between piles of materials in a yard, inside cars and lorries, underground car parks etc. To summarize, if an area is pitch black with no ambient light at all no intensifier will be able to intensify light that doesnít exist. It is rather like playing a blank CD, you can turn up the volume as much as you like, but the amplifier canít amplify something that is not there. The principle with Night Vision Devices is exactly the same, and for this reason infrared lamps still have a vital role. Firstly, they are comparatively cheap, bearing in mind that American Police type lamps cost around £50, and even 1,000.000 candle power lamps, which give incredible performance, are under £200. They are therefore the cheapest way to get massive increases in performance. For example, if you paid £1000 for a system and £200 for a 1,000.000 candle power lamp, you would have the performance of a system costing several thousand pounds more. The only time you would hit a serious problem would be if someone else was using a scope, and the lamp advertised your position. Secondly, there is the problem of no go areas. An Infra Red lamp opens up these areas effectively, and for this reason you should consider having some sort of infra red illuminator to hand in case itís needed, or to assist the scope on a night when thick cloud restricts moon and starlight.

We now come to the various types of illuminator which basically consist of two options. Laser Illuminators and Infrared Lamps. Both are highly effective, but our personal recommendation is that you opt wherever possible for a lamp. As a rule, the range is greater, and in addition it will not generally damage the eye if you look directly at it, whereas some lasers can actually cause retina damage if you look straight at them. These lasers are what is simply termed in the industry as non-eye safe. A reputable dealer will generally know what is, and what is not eye safe on the market. For obvious reasons it is an area where certainty is crucial, especially if children are involved, as due to the fact that no pain is suffered, people can be unaware that they have damaged their eyes until it is too late.

THERMAL IMAGERS (TI).

Thermal imaging is the latest type of equipment, and whilst it performs a similar function to an image intensifier, in other ways it has certain very distinct advantages. Firstly, it solves the problem mentioned earlier, that when in zero light situations an image intensifier cannot operate without the help of infra red light Although this is acceptable in civilian circumstances, it poses great difficulties on the battlefield. Infra red lamps are completely out of the question in this area, and thermal imaging wins hands down, not only because it can operate in Zero light conditions, but it can also operate in fog, smoke, snow and even when camouflage nets have been used to conceal men and tanks.

HOW IT WORKS.

Thermal imaging works in the visible band of 0.4 to 0.7 Microns, and from 0.7 to 12 Microns in the infra red spectrum. Although thermal imagers have been around for some time, it is only recently that they have become a potential rival for the latest image intensifiers. This is because until the current solid state models were developed, all thermal imageries required a cooling system which was usually in the form of a nitrogen or compressed air cooling bottle. Therefore they were extremely bulky, and due to this restriction caused by size and weight, they were only suitable for tripod mounting, fixed surveillance positions or reconnaissance. The way in which the new models score is that they are uncooled, and having dispensed with the bulky gas bottles that are no longer required, they have become portable. For example, the Pilkington Lite weighs only 3.5kg. Also, with the new systems now being solid state technology, they are easier to manufacture in large numbers, and much less fragile than their predecessors.

For certain applications a thermal imager is vastly superior to an image intensifier, in that it can find a person under snow, and troops and vehicles hiding under trees. Methods do exist to defeat it, but it is difficult. The best battlefield defence is a special smokescreen created by firing salvos from 66mm projectors fitted to AFV hulls. These projectors use M76 grenades which produce a smokescreen of hot fragments that descend slowly and can be topped up with more salvos. Special camouflage nets that dissipate heat slowly can also be used, these are sold by Barracuda in Sweden, and Bridport in the UK.

The drawback at the current time of thermal imaging is cost. With a basic system at around £10,000, thermal imaging is expensive, especially when you consider an excellent image intensifier is only a fraction of this cost. It must also be considered, that as with any system, it is only as good as the operator behind it. As range increases people and cars simply become a hot blob. For this reason, we believe it will be some time before thermal imaging takes over from a good image intensifier in civilian applications, but it definitely has its place, especially for tracking fugitives in open country, or finding adults or children lost in remote areas.

THE FUTURE.

It has become clear that third generation image intensifiers are probably the final generation, and from here on we will just see technical improvements, rather than the emergence of third plus or fourth generation systems. The most likely future developments will go down the route of combining thermal imagers and image intensifiers into one unit. This is probably out of the question at the moment, as the system would be too bulky and we donít yet have the technology to get it right. However, the ability to alternate from one technology to the other at the flick of a switch would be a huge breakthrough, and the logical path to follow. For this reason it seems a virtual certainty that light weight combined systems will be in production within 10 years, or perhaps sooner if circumstances demand it.


Generation 2 - Usually an S-25 (extended red) photocathode (with photosensitivity of 240-400 uA/lm) with a microchannel plate
(MCP) to achieve gain. Normally uses fibre-optic inversion. Gen II tubes provide good performance in low light levels and exhibit
very low distortion making them well suited for use with video or still cameras. They are equipped with automatic gain control,
flash protection and feature edge-to-edge definition. Resolution in the centre varies between 30-35 Ip/mm. They are more tolerant
of urban lighting than Gen 3 systems.


Generation 2+ - Based on Gen 2 tube technology, but has enhanced photocathode sensitivity (typical photosensitivity of 500-
600+ uA/lm). Resolution in the centre varies between 35-45 Ip/mm.

SuperGen - Based on Gen 2 tube technology, but with further enhanced photocathode sensitivity (photosensitivity of 600-700+
uA/lm). Resolution in the centre varies between 45-60 Ip/mm.

Generation 3 - Uses gallium-arsenide for the photocathode and a microchannel plate for gain. The microchannel plate is also
coated with a protective ion barrier film to increase tube life. Can produce more than 800 uA/lm in the 450 to 950 nanometer
(near-infrared) region of the spectrum. Gen 3 provides very good to excellent low-light-level performance and long tube life. Mil-
spec Gen 3 tubes show virtually no distortion. Resolution in the centre varies between 32-64 Ip/mm. Current US spec is Omnibus
4. In almost all countries where they can be sold, Gen 3 systems are limited to strictly military use.

Generation 4 - It now appears that the US may be classifying Omnibus 5 tubes as Gen 4 because they have been able to do away
with the protective ion barrier inherent in Gen 3 systems.

 

 

 

Cobra Optics Night Vision Equipment professional night vision equipment, the range includes monocular, binocular,  biocular, goggle (NVG) and weapon scope designs. See in complete darknessIntensifier tubes available include Gen 1, Gen 1+, Gen 2, Gen 2+, SuperGen, HyperGen and Gen 3.

Aids for disabled people inc mobility, paediatric and comfort

 

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