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General Starlight Co. Advanced Photonics Buying Guide

Canada based General Starlight Company Inc. (GSCI) manufacture some of the worlds most advanced image intensified night vision and thermal imaging devices available to buy as an end user legally, without any complications. 

As all GSCI products are made in Canada, there are no ITAR restrictions meaning you can own one of these incredible image intensified night vision devices legally. 

Night Master is an approved UK importer of GSCI night vision products, for units that are being dispatched to the UK we handle all import documents, duty and VAT.

Each device is made to exacting standards, which is why they are chosen by many police and military divisions worldwide. The equipment is also widely used for fieldsports applications, giving the user excellent clarity, quality and continued confidence with a 7-year warranty.

Generations in Night Vision

Image intensifier tubes are classed by generation (GEN) numbers assigned by the US Army's Night Vision Laboratory. Each GEN denotes a new contract or manufacturing process.

  • Generation I: It started with electrostatically focused Generation I tubes featuring high image resolution, a wide dynamic range and low noise.
  • Generation II: Introduced the microchannel plate for much higher gain in the 1980’s. The original image resolution was less than that of the first generation intensifiers but the gain was much higher.
  • Generation II+: Later advancements in GEN II technology brought the tactical characteristics of "GEN II+" devices (equipped with better optics, SUPERGEN tubes, improved resolution and better signal-to-noise ratios) into the range of GEN III devices, which has complicated comparisons.
  • Generation III: In the late 1980’s an Image Intensifier with a GaAs photocathode was developed showing an enhanced sensitivity in the Near-Infrared. In the late 1990’s GEN-III tubes with greatly improved performance appeared on the market.
  • Generation IV: U.S. Army Night Vision and Electronic Sensors Directorate (NVESD) is part of the US governing body that dictates the name of the generation of night vision technologies. Although the recent increased performance associated with the GEN-III OMNI-VI (and above) components is impressive, the U.S. Army has not yet authorised the use of the name GEN-IVWeaver Mounting System for these components. This means the term GEN-IV is used more as a marketing tool than it is valid terminology, often used to describe high-end GEN-III tubes with an autogating power supply.

Image Intensifier Tubes

MA1 GEN2+ FOM 1250-1599 OPTIONAL
GA3 GEN3 FOM 1800-1999
GA4 GEN3 FOM 2000-2399
GA5 GEN3+ FOM 2400+
EC ECHO FOM 1600-2000 YES
4G 4G FOM 1800+ YES

      EC Elite and 4G Elite Plus Tubes are available for professional use only, please contact us for buying information.

      FOM is an abstract measure of image intensifier tube performance, derived from the number of line pairs per millimetre multiplied by the tube's signal-to-noise ratio (Resolution x SNR). Therefore the higher the FOM, the better the image.

      All GSCI image intensified tubed night vision devices are autogated, nitrogen purged and available in green or white phosphor.

      Depending on the device the tube is fitted into manual gain control may be included (or available as an optional extra).

      How far can you see with Night Vision?

      The chart below shows the detection range of various tubes, in different conditions without any additional infrared (IR) illumination.

      GSCI intensified tube range of detections

      Technical data and terms, what do they mean?

      Automatic Brightness Control (ABC)

      This electronic feature automatically reduces voltages to the microchannel plate to keep the image intensifier’s brightness within optimal limits and protects the tube.

      This is most apparent when rapidly changing from low-light to high-light conditions; the image gets brighter and then, after a momentary delay, suddenly dims to a constant level.

      Auto-gated Power Supply

      Auto-Gating reduces the duty cycle of the cathode voltage by rapidly switching the voltage on and off. It is a proprietary means to preserve the high MTF (Modulation Transfer Function) and resolution that is obtained at the full operating voltage while reducing the strain of high illumination levels on the image intensifier tube. This is done by reducing the average current coming from the photocathode.

      Auto-Gating constantly operates to improve the quality of the image, not only during day-night-day transition, but also under dynamic lighting conditions such as military/law enforcement operations in urban environment which define many of today's missions.

      Bright-Source Protection (BSP) - Highlight Cut-Off

      An electronic function that reduces the voltage to the photocathode when the night vision device is exposed to bright light sources, such as room lights or car lights. BSP protects the image tube from damage and enhances its longevity. However, BSP may have the effect of lowering resolution when it is functioning.

      Daylight Lens Cover / Daytime Filter

      Generally made of a soft plastic or rubber cap with a pinhole that allows a small amount of light to enter the objective lens of a night vision device. This should be used for training purposes only, and is not recommended for an extended period of time. Near field focus only usable in this fashion.

      Daytime Training Filter

      A glass filter assembly designed to fit over the objective lens of a night vision device. The filter reduces light input to a safe (night-time) level, allowing safe extended daytime use of the night vision device.

      Eye Relief

      The distance a person’s eyes must be from the last element of an eyepiece in order to achieve the optimal image area.

      Field-of-View (FOV)

      The width or spatial angle of the outside scene that can be viewed through the intensifier tubes measured laterally and vertically.

      Figure of Merit (FOM)

      FOM is an abstract measure of image intensifier tube performance, derived from the number of line pairs per millimetre multiplied by the tube's signal-to-noise ratio (Resolution x SNR).

      Therefore the higher the FOM, the better the image. It is difficult to have an objective measure of quality for a night vision device since it is intrinsically reliant on external factors such as available light and weather conditions. Therefore the FOM is universally recognised as a measurable value to adequately determine the performance of the image intensifier tube.

      Gain (in Night Vision)

      Also referred to as brightness gain or luminance gain; this is the number of times an image intensifier tube amplifies light input. It is usually measured as tube gain and system gain. In any night vision system, the tube gain is reduced by the system's lenses and is affected by the quality of the optics or any filters; therefore, system gain is a more important measurement to the user.

      IR (Infrared) Illuminator

      Many night vision devices incorporate a built-in (IR) diode that emits invisible light or the illuminator can be mounted on to it as a separate component. The unaided eye cannot see IR light; therefore, a night vision device is necessary to see this light. IR Illuminators provide supplemental infrared illumination of an appropriate wavelength, typically in a range of wavelengths (e.g. 730nm, 830nm, 920nm), and eliminate the variability of available ambient light, but also allow the observer to illuminate only specific areas of interest while eliminating shadows and enhancing image contrast.


      The magnifying power of the lens. Four power (4X) indicates that the image will appear four times larger than if viewed with a 1X lens.

      Phosphor Screen

      A very thin layer of phosphor is applied to the output fiber optic system, and emits light when struck by electrons. The purpose of the phosphor screen is to convert electrons into photons.

      Sacrificial Window

      A clear glass filter assembly designed to fit over the objective lens of a night vision device and designed to protect the optics against physical damage (chips, scratches, etc).

      Variable (Manual) Gain Control (in Night Vision)

      Allows the user to manually adjust the gain control (basically like a dim control) in varying light conditions. This feature sets the PVS-14 apart from other popular monoculars that do not offer this feature.

      Ordering process

      GSCI products are custom-made to order, current lead times are generally 2 to 3 weeks from receiving payment for your order until your device is ready to be dispatched by GSCI. Once your device is dispatched by GSCI, we expect for you to receive your order within 1 week (for UK or International).

      GSCI products are made in Canada, this means there are no ITAR restrictions (for UK or International).

      • Step 1 - Place and pay for your order (contact for lead time estimate)
      • Step 2 - Your order will begin the production process with GSCI in Canada
      • Step 3 - While your order is in production, we will complete any import documents required to get your device(s) into the UK (if this is being shipped internationally we will email you import documents to be completed and returned with proof of ID)
      • Step 4 - Once your order is completed, GSCI will dispatch your device(s) to us via courier (if this is being shipped internationally your order will be shipped to you directly from Canada) - this usually takes up to five working days.
      • Step 5 - Your order will arrive safely with us (UK), once we have done final checks we will dispatch your order to you via courier