aperture illumination efficiency
11Reflector (antenna) — An antenna reflector is a device that reflects electromagnetic waves.It is often a part of an antenna assembly.The most common reflector types are * corner reflector which reflects the incoming signal back to the direction it came from *… …
12photography, technology of — Introduction equipment, techniques, and processes used in the production of photographs. The most widely used photographic process is the black and white negative–positive system (Figure 1 >). In the camera the lens projects an image of… …
13Passive solar building design — Elements of passive solar design, shown in a direct gain application …
14Optics — For the book by Sir Isaac Newton, see Opticks. Optical redirects here. For the musical artist, see Optical (artist). Optics includes study of dispersion of light. Optics is the branch of …
15Light meter — A light meter is a device used to measure the amount of light. In photography, a light meter is often used to determine the proper exposure for a photograph. Typically a light meter will include a computer, either digital or analogue, which… …
16cosmos — /koz meuhs, mohs/, n., pl. cosmos, cosmoses for 2, 4. 1. the world or universe regarded as an orderly, harmonious system. 2. a complete, orderly, harmonious system. 3. order; harmony. 4. any composite plant of the genus Cosmos, of tropical… …
17Holography — (from the Greek, ὅλος hólos whole + γραφή grafē writing, drawing) is a technique that allows the light scattered from an object to be recorded and later reconstructed so that it appears as if the object is in the same position relative to the… …
18Observational astronomy — Mayall telescope at Kitt Peak National Observatory Observational astronomy is a division of the astronomical science that is concerned with getting data, in contrast with theoretical astrophysics which is mainly concerned with finding out the… …
19BMP-1 variants — This is a complete list of variants and designations of the BMP 1 infantry fighting vehicle. It is sorted by country of origin. Variants Former USSRInfantry fighting vehicles* BMP (Ob yekt 764) Original main prototype of BMP 1 developed by the… …
20Exposure (photography) — Underexposure redirects here. For the 2005 film by Oday Rasheed, see Underexposure (2005 film). A long exposure showing stars rotating around the southern and northern celestial poles. Credit: European Southern Observatory …
