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Abbe number. In optics and lens design, the Abbe number, also known as the V-number or constringence of a transparent material, is an approximate measure of the material's dispersion (change of refractive index versus wavelength), with high values of V indicating low dispersion. It is named after Ernst Abbe (1840–1905), the German physicist ...
The AN/PEQ-2 has two infrared laser emitters;one narrow beam used for aiming the rifle and one wide beam used for illuminating targets, like a flashlight. The beams can only be seen through night vision goggles. Each beam can be zeroed independently, and the illuminator's radius is adjustable. The two lasers are tied into one 6-mode switch ...
The Advanced Target Pointer / Illuminator / Aiming Light, ATPIAL AN/PEQ-15 known colloquially as the "PEQ-15" [/ p ɛ k / / f ɪ f t iː n /] produced by L3Harris (originally designed and manufactured by Insight Technology, until their acquisition by L3Harris in 2010); is a multifunction IR Target Pointer & Illuminator, a.k.a. a Laser Aiming Module (LAM) for use as a rifle attachment, using a ...
Laser sight (firearms) A laser sight is a device attached or integral to a firearm to aid target acquisition. Unlike optical and iron sights where the user looks through the device to aim at the target, laser sights project a beam onto the target, providing a visual reference point. Although lasers in the visible part of the spectrum are most ...
A 1951 USAF resolution test chart is a microscopic optical resolution test device originally defined by the U.S. Air Force MIL-STD-150A standard of 1951. The design provides numerous small target shapes exhibiting a stepped assortment of precise spatial frequency specimens. It is widely used in optical engineering laboratory work to analyze and ...
In optics, the Abbe sine condition is a condition that must be fulfilled by a lens or other optical system in order for it to produce sharp images of off-axis as well as on-axis objects. It was formulated by Ernst Abbe in the context of microscopes. [1] The Abbe sine condition says that. the sine of the object-space angle should be proportional ...
The longer the focal length of the eyepiece, the greater the eye relief. Typical telescopic sights may have eye relief ranging from 25 mm (0.98 in) to over 100 mm (3.9 in), but telescopic sights intended for scout rifles or handguns need much longer eye relief to present a non-vignetted image.
Abbe condensers are difficult to use for magnifications of above 400X, as the aplanatic cone is only representative of a numerical aperture (NA) of 0.6. This condenser is composed of two lenses, a plano-convex lens somewhat larger than a hemisphere and a large bi-convex lens serving as a collecting lens to the first.