How Did The Sniperscopes Used In World War II Work They Seem To Have Used An In… [PORTABLE]
Early U.S. designations, such as the M3 Sniperscope, included both a rifle modified to hold the infrared viewing system. A sniperscope, required a source of infrared light. Often, such a device had two side-by-side tubes, resembling a flashlight and telescope clamped together. The early versions also needed a rifle modified to hold the equipment. Later technologies do not require an "invisible spotlight" such as were used on the early "sniperscopes" in the Second World War. [1]
How did the sniperscopes used in World War II work They seem to have used an in…
Night vision devices can be handheld but many are head-mounted and attach to helmets. When used with firearms, an IR laser sight is often mounted to the user's weapon. The laser sight produces an infrared beam that is only visible through an NVD and aids with aiming.[3] Some night vision devices are specially made to be mounted to firearms. These can used in conjunction with weapon sights like rifle scopes or can be used as standalone sights; some thermal weapon sights have been designed to provide similar capabilities.[4]
These devices were first used in World War II and came into wide use during the Vietnam War.[5] The technology has evolved greatly since its introduction, leading to several "generations"[6] of night-vision equipment with performance increases and price reductions. Consequently, though they are commonly used by the military and law enforcement agencies, night vision devices are available to civilian users for a wide range of applications including aviation, driving, demining, etc.[7]
Fusion night vision is a newer advance in night vision technology which combines I (image intensification) with thermal imaging, which functions in the medium (MWIR 3-5 µm) and/or long (LWIR 8-14 µm) wavelength range.[40] Initial models appeared in the 2000s and progressed in the 2010s.[31] Some devices are dedicated fusion devices while others are clip-on thermal imagers which can add a thermal overlay to standard I night vision devices.[41] Fusion technologies combines the strengths of traditional I, which is excellent for navigation and discernment of fine details, with the strengths of thermal imaging, which excels in spotting the heat signatures of targets. Fusion systems have offered a number of different imaging modes including "fused" night vision with thermal overlay, night vision only, thermal only, and various special fusion modes like outline (which outlines objects that have thermal signatures) or "decamouflage", which highlights all objects that are of near-human temperatures. Fusion devices do struggle with weight and power usage and are often heavier and have shorter run times than contemporary I-only devices.[42]
Night vision devices, whether monocular or binocular, typically have a limited field of view (FoV); the commonly used AN/PVS-14 has a FoV of 40[64] which is rather less than the 95 monocular horizontal FoV and 190 binocular horizontal FoV that humans possess.[65] Due to the limited FoV, users must visually scan about to fully check their surroundings, which is a time consuming process. This limitation is particularly evident when using night vision devices for flying, driving, or CQB where split second decisions must be made. Because of these limitations, many SOF troops preferred to use white light rather than night vision when conducting CQB.[66] As a result, much time and effort has gone into research to develop a wider FoV solution for night vision devices. As of 2021, there were three primary methods for increasing peripheral vision in night vision devices (each with their own advantages and disadvantages):
Panoramic night vision goggles (PNVG) increase field of view by increasing the number of sensors: if tubes are generally limited to 40, then one can add more tubes to increase peripheral vision. This solution works well and does not compromise device performance or visual clarity but comes at the cost of size, weight, power requirements, and complexity.[67] A well-known set of peripheral NVGs is the GPNVG-18 (Ground Peripheral Night Vision Goggle), which was used in the raid in Abottabad that killed Osama Bin Laden.[68] These goggles, and the aviation AN/AVS-10 PNVG from which they were derived, offer a 97 FoV.[66]
Diverging image tube (DIT) night vision increases FoV by positioning the night vision tubes so they are no longer parallel but are angled slightly outward. This increases peripheral FoV but causes distortion and reduced image quality. Unfortunately, optical clarity is best when looking through the center of an image intensifier tube. With DIT, users are no longer looking "straight through" the center of the tubes (which provides the clearest images) and light passing through the center of the tubes no longer falls on the fovea (the area of clearest vision). The AN/PVS-25 was one such example of DIT night vision from the late 2000s.[67] The WFoV BNVD is a variant of the AN/PVS-31A which incorporates both F-NVG and DIT-NVG concepts: the foveal WFoV optics increase the FoV of each tube from 40 to 55, while the slight angulation of the tubes positions them so there is a 40 overlap of binocular vision in the center and a total 70 bi-ocular FoV. With the performance of the modified AN/PVS-31A tubes used, the WFoV BNVD has a FoM of 2706 which is better than the FoM in both the GPNVG-18 and the standard AN/PVS-31A.[72][67]
The first documented telescopic rifle sight was invented between 1835 and 1840. In a book titled The Improved American Rifle, written in 1844, British-American civil engineer John R. Chapman documented the first telescopic sights made by gunsmith Morgan James of Utica, New York. Chapman gave James the concepts and some of the design, whereupon they produced the Chapman-James sight. In 1855, optician William Malcolm of Syracuse, New York began producing his own telescopic sight, used an original design incorporating achromatic lenses such as those used in telescopes, and improved the windage and elevation adjustments. These Malcolm sights were between 3 and 20 magnification (possibly more). Malcolm's sights and those made by Vermont jeweller L. M. Amidon were the standard sharpshooter equipments during the American Civil War.[4][5]
Reticle patterns can be as simple as a round dot, small cross, diamond, chevron and/or circle in the center (in some prism sights and reflex/holographic sights), or a pointed vertical bar in a "T"-like pattern (such as the famous "German #1" reticle used on the Wehrmacht ZF41 sights during the Second World War, or the SVD-pattern reticle used on the Soviet PSO-1 sights during the Cold War) that essentially imitates the front post on iron sights. However, most reticles have both horizontal and vertical lines to provide better visual references.
Crosshair reticles are typically not graduated, and thus are unsuitable for stadiametric rangefinding. However some crosshair designs have thickened outer sections that help with aiming in poor contrast situations when the crosshair center cannot be seen clearly. These "thin-thick" crosshair reticles, known as duplex reticles, can also be used for some rough estimations if the transition point between thinner and thicker lines are at a defined distance from the center, as seen in designs such as the common 30/30 reticles (both the fine horizontal and vertical crosshair lines are 30 MOAs in length at 4 magnification before transition to thicker lines). There can also be additional features such as enlarged center dot (frequently also illuminated), concentric circle (solid or broken/dashed), chevron, stadia bars, or a combination of the above, that are added to a crosshair to help with easier aiming.
Telescopic sights based on image erector lenses (used to present to the user with an upright image) have two planes of focus where a reticle can be placed: at the focal plane between the objective and the image erector lens system (the First Focal Plane (FFP)), or the focal plane between the image erector lens system and the eyepiece (the Second Focal Plane (SFP)).[22][23] On fixed power telescopic sights there is no significant difference, but on variable power telescopic sights a first focal plane reticle expands and shrinks along with the rest of the image as the magnification is adjusted, while a second focal plane reticle would appear the same size and shape to the user as the target image grows and shrinks. In general, the majority of modern variable-power sights are SFP unless stated otherwise.[24] Every European high-end telescopic sight manufacturer offers FFP reticles on variable power telescopic sights, since the optical needs of European hunters who live in jurisdictions that allow hunting at dusk, night and dawn differ from hunters who traditionally or by legislation do not hunt in low light conditions.[citation needed]
Variable-power telescopic sights with FFP reticles have no problems with point of impact shifts. Variable-power telescopic sights with SFP reticles can have slight point-of-impact shifts through their magnification range, caused by the positioning of the reticle in the mechanical zoom mechanism in the rear part of the telescopic sight. Normally these impact shifts are insignificant, but accuracy-oriented users, who wish to use their telescopic sight trouble-free at several magnification levels, often opt for FFP reticles. Around the year 2005 Zeiss[25] was the first high-end European telescopic sight manufacturer who brought out variable magnification military grade telescopic sight models with rear SFP mounted reticles. They get around impermissible impact shifts by laboriously hand-adjusting every military grade telescopic sight. The American high-end telescopic sight manufacturer U.S. Optics Inc.[26] also offers variable magnification military grade telescopic sight models with SFP mounted reticles.
Most telescopic sights lack parallax compensation due