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ATS officers-in-training crew a 90 cm searchlight in Western Command, 1944. A searchlight (or spotlight) is an apparatus that combines an extremely bright source (traditionally a carbon arc lamp) with a mirrored parabolic reflector to project a powerful beam of light of approximately parallel rays in a particular direction.
The projector is normally set at 90°, although 71° 31' may be used, in relation to the terrain. The projector consists of a 430-watt incandescent bulb set in a weatherproof housing. Inside the housing are two mirrors; the first, above the bulb, reflects the light downwards to the second mirror, that then reflects the light upwards to the ...
The current versions has only one band of observation, that can produce misinterpretations if the light pollution changes from sodium-vapor lamp to LED. [8] The SQM-L, or "Sky Quality Meter - L," is a model with an additional integrated lens, offering a narrower measurement range of 20° compared to the 84° range of the standard SQM model. [9]
A barn door tracker, also known as a Haig or Scotch mount, is a device used to cancel out the diurnal motion of the Earth for the observation or photography of astronomical objects. It is a simple alternative to attaching a camera to a motorized equatorial mount .
An astronomical survey is a general map or image of a region of the sky (or of the whole sky) that lacks a specific observational target. Alternatively, an astronomical survey may comprise a set of images, spectra, or other observations of objects that share a common type or feature.
Sky-Map.org (or WikiSky.org) is a wiki and interactive sky map that covers over half a billion known celestial bodies. [1] WikiSky is designed, in part, as a wiki.Users can edit information about different stars by writing articles, adding Internet links, uploading images, or creating a special interest group for a specific task.
The Rayleigh sky model describes the observed polarization pattern of the daytime sky. Within the atmosphere, Rayleigh scattering of light by air molecules, water, dust, and aerosols causes the sky's light to have a defined polarization pattern. The same elastic scattering processes cause the sky to be blue.
A star tracker is an optical device that measures the positions of stars using photocells or a camera. [1] As the positions of many stars have been measured by astronomers to a high degree of accuracy, a star tracker on a satellite or spacecraft may be used to determine the orientation (or attitude ) of the spacecraft with respect to the stars.