Kaprelian, Edward K. Formerly, Keuffel and Esser Company, Morristown, New Jersey.
Kraft, Timothy W. Department of Vision Sciences, School of Optometry, University of Alabama, Birmingham, Alabama.
- Rifle sights
- Aircraft gunsights
- Artillery sights
- Additional Readings
Optical instruments that establish an optical line or axis for the purpose of aiming a weapon. The axis includes the observer's eye, a suitable mark in the instrument, and the target. For a pistol, the traditional iron sights employ a rear notch and a front post with midpoints that are aligned with each other and that of the target, while the flat top of each piece creates a horizon that is aligned with the vertical center of the target (Fig. 1). For dim light conditions, sighting is aided by high-contrast white dots or bars placed on the rear and front sights. Substituting tritium paint or vials of tritium gas creates a light source for superior visibility. “Night vision” aiming is possible with the use of image intensifiers and near-infrared [wavelengths of 820–950 nanometers (nm)] diodes or lasers, or true thermal imaging [using thermal radiation from warm objects at wavelengths greater than 4 micrometers (μm)], all of which require a mounted optical instrument (discussed below). The unaided rifle sight employs front and rear elements far enough apart that the two are not in simultaneous focus. Typically the rear sight is a ring or loop that appears as a fuzzy circle around the front post. Concentric rings are perceptually easy to center with respect to one another, and thus a front aperture sight is often used (Fig. 2). See also: Infrared imaging devices; Infrared radiation; Light amplifier; Tritium
The content above is only an excerpt.
for your institution. Subscribe
To learn more about subscribing to AccessScience, or to request a no-risk trial of this award-winning scientific reference for your institution, fill in your information and a member of our Sales Team will contact you as soon as possible.
to your librarian. Recommend
Let your librarian know about the award-winning gateway to the most trustworthy and accurate scientific information.
AccessScience provides the most accurate and trustworthy scientific information available.
Recognized as an award-winning gateway to scientific knowledge, AccessScience is an amazing online resource that contains high-quality reference material written specifically for students. Its dedicated editorial team is led by Sagan Award winner John Rennie. Contributors include more than 9000 highly qualified scientists and 42 Nobel Prize winners.
MORE THAN 8500 articles and Research Reviews covering all major scientific disciplines and encompassing the McGraw-Hill Encyclopedia of Science & Technology and McGraw-Hill Yearbook of Science & Technology
115,000-PLUS definitions from the McGraw-Hill Dictionary of Scientific and Technical Terms
3000 biographies of notable scientific figures
MORE THAN 17,000 downloadable images and animations illustrating key topics
ENGAGING VIDEOS highlighting the life and work of award-winning scientists
SUGGESTIONS FOR FURTHER STUDY and additional readings to guide students to deeper understanding and research
LINKS TO CITABLE LITERATURE help students expand their knowledge using primary sources of information