Planetarium Technology

Night vision devices (NVD’s) have advanced considerably in recent years and this sophisticated technology is now easily available for anybody interested in outdoor pursuits such as camping, fishing, hunting, astronomy or sailing. Night vision devices work by capturing existing ambient light through the front lens. This light, which is made up of photons goes into a photocathode tube that transforms the photons into electrons. The electrons are then thrown against a phosphorus screen that changes the amplified electrons back into visible light which can be seen through the eyepiece. This image will appear as a clear, green-hued re-creation of the originally observed scene.

The main difference between various night vision devices is which type of image intensifier tube is used. A Night Vision Device can be either a 1st, 2nd or 3rd generation:

Generation I A GEN 1 unit will amplify the existing light several thousand times to provide an image that is magnified and easily viewed by the night scope’s eyepiece (ocular). These units are the most reasonably priced night vision devices and so provide the greatest value to people seeking night vision capabilities.

Generation II GEN 2 devices use a micro-channel plate to achieve lower image distortion as well as higher light amplification characteristics. This extra process allows GEN 2 units to amplify the light many more times than their GEN 1 counterparts, creating a significantly brighter and sharper image.

Generation III These devices have gallium arsenide added to the intensifier tube and a special protective film on the micro-channel plate, which increases the life of the tube, thus providing the user with good to excellent low light performance. GEN 3 devices are military standard.

For more information and to view a comprehensive range of NVD’s, visit www.sherwoods-photographic.com, a family owned company who specialise in telescopes and binoculars.