Night Vision Instruments

SELECTING THE RIGHT MODEL FOR YOUR APPLICATION

Choosing a suitable model for your particular application and requirements will need some considerations to be taken in to account. These need to be explored rather carefully.

Night Vision devices are categorised in to 3 different quality levels, 1st Generation, 2nd Generation and 3rd Generation, of which only the first two are available for commercial use. The 3rd Generation instruments are used exclusively by the military, both in South Africa and many other countries.

1st Generation (or Gen-1) instruments are capable of viewing distances ranging from 150 to 300 meters and the only variables that will influence these distances are the magnifying power of the lens and the ambient (available surrounding) light. We refer here to full moon, half moon, quarter moon, starlight with a clear sky or overcast and total darkness. A typical example of this is shown in the tables below:

MAGNIFICATION Full Moon Half Moon Quarter Moon Pitch Dark 1x 150m 125m 100m 75m 3x 250m 200m 150m 100m 5x 300m 250m 200m 150m

2nd Generation (or Gen-2) instruments utilise more advanced electronics, which results in longer viewing distances as well as far brighter images. The Electronic Intensifier Tube (EIT) is of a more advanced design and usually includes an automatic gain control, which will protect the EIT from too bright a light doing damage to it. Today, almost all of the world’s EITs are manufactured in Russia. LUNA OPTICS NV devices are made entirely in Belarus (Russia).

MAGNIFICATION Full Moon Half Moon Quarter Moon Pitch Dark 1x 300m 250m 200m 175m 3x 450m 400m 350m 300m 5x 600m 550m 500m 400m

What about being in total darkness?

All night vision devices require a small amount of light (ambient or directed) to enable it to form an image, in the absence of which the device cannot work. All the models in the LUNA OPTICS range of Night Vision (NV) devices are supplied with a built-in Infra Red Illuminator which will provide sufficient Infra Red light up to a maximum of 100m to allow the instrument to form an image in total darkness. The 1^st Generation Rifle Scope is fitted with a 2-stage IR illuminator which can send an IR beam up to 200 meters. The 2^nd Generation Rifle Scope is fitted with a 3-stage IR illuminator for a longer beam range. Infra Red light is invisible to the human and animal eye, however, the NV device will see the IR beam as a bright light.

Several models in the LUNA Optics range also provide the facility to attach an Extended Range Infra Red Illuminator. This is necessary for the higher magnification models that are able to see further than 100m. These compact illuminators are able to provide the NV device with an extended beam distance of up to 200m, or even a 1000m as is the case of the LASER illuminator. The laser illuminator has an adjustable front lens, which allows the user to either spread the IR light beam to approximately 80% of the field of view, or narrow the beam down to a spot (±5%). This spot setting will allow a Gen-1, 5x binocular, for example, to see up to 500m in total darkness and also be able to clearly identify the “bloudraad” on a fence, or the face of a person standing there. Remember that Infra Red light is invisible to the human eye, but the NV device sees it as bright light beam.

MONOCULARS, BINOCULARS or GOGGLES – Which one is for me?

MONOCULAR instruments have one ocular (eye piece) and one front lens. These are considered as entry level models and were designed to provide the “non-heavy duty” user with a relatively inexpensive instrument. Although the internal electronics and the optical lenses are identical to their binocular counterparts, the body work is made of a very sturdy plastic and a single optical path is used which allows for a lower cost.

BINOCULAR instruments utilise two optical paths, viz. two oculars (eye pieces) and two front lenses. This system enhances the perception of depth. Three of the LUNA Binoculars are constructed of aluminium alloy to enhance their sturdiness for rough conditions.

There is one other model which is a variation of the two described above, which is known as a BI-OCULAR, where two oculars (eye pieces) are employed but only one lens is fitted on the front of the instrument. The advantage of this design is that you can now fit only one (optionally available) larger magnification lens.

GOGGLES are specifically designed to be used when driving a vehicle. For this reason only a 1x magnification lens is fitted to ensure that the image is the same as seen by the naked eye in daylight. If the lens magnifies the image whilst driving a vehicle, the user will take the bend before they get there. The headgear supplied is capable of flipping the NV device up and down, or it can be detached for hand use. It should be mentioned that experience has shown that goggles are not the most convenient for walking with in rough terrain. The rubber eye cups will effectively shield one’s eyes from extraneous light and/or reflections, preventing you from seeing where you are placing your feet.

RIFLE SCOPES - As the name implies, these models are designed for use on a rifle, are shock and weather resistant, ruggedly built and reasonably heavy. The 1^st Generation model can be used on rifles with a maximum calibre of .308 (WIN), the Gen-2 model on rifles with maximum calibre of .50 BMG. These units have either a 2-stage or a 3-stage built-in IR illuminator and adjustable illuminated reticules. They also provide an easy-to-use elevation and windage adjustment for alignment with the rifle. They are highly accurate and stable.

Other advanced features included in some of the models:

• “Daylight Protection Sensor”, which prevents the user from accidentally switching the device ON in broad daylight which could damage the “Electronic Intensifier Tube” or EIT,
• “Active Brightness Control” which will automatically adjust the unit’s gain whilst looking through the device in darkness and then suddenly looking into a very bright light.

• All the models without these features necessitate that the user keeps the lens caps on during the day or other bright light conditions.

Your choice between 1^st and 2^nd Generation will depend on how clearly you want to see the target image and if you require vision over longer distances. For this reason the Gen-2 instruments command a much higher price tag.

NB: NEVER, EVER, SWITCH THE NV DEVICE ON IN BROAD DAYLIGHT

NV devices employ an Electronic Intensifier Tube which amplifies any available light it can see by 900 to 20,000 times depending on the model. If the light source is too bright, the amplification of it will fatally damage the EIT beyond repair. It is, therefore, recommended that the user seriously considers acquiring a NV device that has the necessary protection built in to avoid any possible instrument fatalities.

ADJUSTING THE FOCUS

Night Vision Instruments are not the same as daylight binoculars. Most of the latter use a combination of adjusting the eyepiece and then zooming in on the subject. In NV devices, it is necessary to first look at a distant object before total darkness occurs. Before sunset it is crucial that the lens caps remain on the device, even those with Daylight Protection. The ambient light conditions will soon enough tell you when you can remove the lens caps. Look at a distant object, then adjust the oculars (eye pieces) till you get a reasonable image focus according to your own eye strength. Then the front lenses are focussed for the relevant distance to the subject and need to be re-adjusted for different distances.

POWER SOURCES

We are often asked about the use of rechargeable batteries.

We recommend that ONLY alkaline and lithium batteries are used in those models that use either AA or AAA. Many of the models however utilise special Lithium type batteries that are available from most photographic stores and certain larger hardware stores and supermarkets. It is recommended that the user checks the “freshness” of the batteries purchased as exceptionally few can withstand a long shelf life.

Regarding rechargeable batteries, it must be remembered that at the current stage of the technology, rechargeable batteries are only 1.2 volts unlike the alkaline batteries at 1.5 volt. Now we have 20% less power and the NV device can no longer maintain its full functionality for the amount of working hours specified in the specifications for each device. Rechargeable batteries will do no harm to the NV device, but these batteries will have to be recharged more often than otherwise. If this does not present a problem for the user, then go for it.

It is strongly recommended that batteries are removed from the NV device if it won’t be used for long periods.

MAINTENANCE

Proper care and cleanliness will ensure that you can enjoy and effectively use your night vision device for many years. Optical lenses have a very important coating to allow maximum light transmittance and fend off unwanted reflections. When cleaning of the lenses is necessary, always use a soft cloth and wipe the lenses with circular motion. Never use any detergents or solvents.