Introduction

Chapter 1 of this guide will help explain the intricacies of researching and purchasing night observation devices (NODs) and night vision devices (NVGs) for a person who has no idea what these terms mean. What are ‘tubes’? Which generation device do you need? What is the difference between ‘night vision’ and ‘thermal vision’? These questions and more will be covered. 

Chapter 2 talks about accessories, their uses, and why you should consider them when making your purchase. Chapter 3 is a discussion about ITAR/EAR, and why you should consider these when exporting equipment to Ukraine. 

The final chapters contain assorted resources and charts for your use. Who to contact, where to look for pricing, and so on. 

We hope that this guide will inform your purchase of these devices now and in the future.

Слава Україні!  

Chapter 1: Types of Night Vision Devices

Night Vision vs. Thermal Vision

The primary difference between night vision and thermal vision is how the image is enhanced and what can be seen through each device. Although the term “night vision” can be used to refer to both types, in military usage it is typically only used to refer to light-amplification devices, while the word “thermal” refers to heat detecting devices.

Both types of vision enhancement serve their purposes on the battlefield, but each has pros and cons that must be considered prior to purchase. For this reason, light-amplifying night vision devices (commonly called “NVGs” or “Night Vision Goggles”, even if not really goggles) are used for typical nighttime soldier tasks such as patrolling or driving, and are often paired with IR laser illuminators, while thermal optics are often used for different purposes such as spotting ambushes or mines. Thermal scopes (as opposed to helmet-mounted monocles) are mounted to a weapon and are usually used to spot and shoot enemy soldiers at nighttime. Your soldier can potentially switch between NVGs and thermals (or use both) depending on the situation and use case. 

Night Vision Technical Details

Night Vision Devices (NVDs) are typically called “NVGs” or “NODS” (night optical/observation device) by the US military so we will use the term “NVGs” in this guide. They generally use chemical means similar to a glow-in-the-dark watchface. Incoming light excites a phosphorescent coating inside an ‘amplification tube’, giving energy to the coating and causing it to put off more light on its own. A modern NVG is very good at amplifying weak visible light sources, but this means that NVGs require at least some ambient light in order to operate. If there is no ambient light to amplify, such as in a sealed bunker underground, the NVG does not work very well or at all.

Additionally, because NVGs use a chemical process to amplify light sources, the internal amplification tubes physically wear out and must be replaced periodically. Over time, the phosphorescent coating will stop glowing as brightly, or as accurately, reducing image clarity gradually, causing eye strain. Being exposed to very bright light sources wears out the tubes faster. For that reason, “auto-gating” NVGs are recommended, and will be discussed further in this chapter. 

Generations

NVGs are generally organized by their generation number. A Gen 3 device is much newer technology than a Gen 1 device, for example, and will be more expensive as a result. Newer generations usually mean better image quality, longer serviceable lifespans, smaller size and/or lighter weight. Gen 2 and Gen 3 devices are the standard used on the battlefield right now. 

Gen 1 was first developed around the 1960s. Although it was a giant step forward at the time, these devices today are considered entry-level at best, useful only for civilian light duty at short ranges (100 yards or less). At worst, they are collector’s items. Several amplification tubes are used in series, each amplifying the last. This causes an effect called ‘blooming’, similar to the degradation seen when making a photocopy of a photocopy. Any artifacts or blemishes in the tubes are therefore greatly amplified. To be most useful, a Gen 1 device is often assisted by an external IR light source, a major drawback. Any IR light on a modern battlefield will be visible from miles away by any enemies with their own night vision, giving away one’s position and resulting in mission compromise/death. A Gen 1 device is bulky, short-range, and low-resolution. While fine for hunting or search and rescue and typically very affordable, Gen 0 (requiring IR light assistance) and Gen 1 devices are not appropriate for modern combat.

Gen 2 is more modern, and is used on battlefields today. Gen 2 devices add a ‘micro-channel plate’ (MCP) that further discriminates and amplifies incoming light for increased clarity, especially at the edges of the lens. The MCP also allows fewer amplification tubes to be used, reducing the physical size and weight considerably. Gen 2 devices are still highly capable and suitable for use on modern battlefields.

Gen 3 is the latest generation, used by modern militaries such as the United States. Gen 3 devices upgrade to a gallium arsenide photocathode in addition to the normal amplification tubes and MCP which produces significantly more accurate visible amplification than previous generations, including in the near-infrared spectrum. To further increase clarity and reduce blooming, a chemical film is applied to the MCP. This film helps to discriminate incoming light sources, allowing for more accurate reproduction of the source image without degradation. 

With Gen 3 devices, you can expect a longer useful range than Gen 2, depending on the device standard and manufacturer. Image clarity and brightness is greatly increased over Gen 2, and eye strain is significantly reduced. Gen 3 devices are a further refinement of Gen 2 and typically cost 50% more.

Passive vs. Active

When referring to NVGs, it’s important to know the difference between “active” and “passive”. Passive operation is being able to operate without the use of external light sources. Passive operation is preferred for many reasons. Most importantly because external light sources can be seen by anyone with a NVG, including enemies. When referring to NVGs, passive is much better than active. If a NVG specifies that it is active only, it is not suitable for combat operations. 

Auto-Gate

Gen 3 devices, and less commonly Gen 2, can come with an ‘auto-gating’ feature. This is essentially a shutter that opens and closes multiple times per second to ‘gate’ the amount of light reaching the photosensors. While normally not very noticeable to the user, the gate automatically controls how much light goes into the device, preventing damage to the internal photoelements from bright sources. Bright light sources will overwhelm the amplification tube(s) and reduce operating hours significantly. The auto-gate prevents damage to the internal parts of the NVG.

Auto-Gain

‘Gain’ is the amount of amplification supplied by the tube to the user’s eyes. Gain is a variable number, depending on the settings of the device. Some devices have no gain control, others are manual gain only, and still others can come with an auto-gain in addition to manual gain controls. Too much gain can result in distortion of the image or ‘night-blindness’ from the user seeing too much light. High-quality devices may come with an ‘auto-gain’ feature that automatically adjusts gain based on ambient light levels. Auto-gain, unlike auto-gating, is a feature to help the user by controlling the amplification of light to prevent night- and flash-blindness by turning the gain down. 

Image Intensification/Amplification Tubes

Also just called ‘tubes’. Both Gen 2 and Gen 3 devices come with either green phosphor (GP) or white phosphor (WP) tubes. GP is the standard, but WP provides better image clarity, lower eye strain, and longer lifespan at increased cost. Either will work, and both are in military service today, but WP is generally preferred by the end user.