steradian


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steradian
If A = r2 then solid angle Ω = 1 sr.

ste·ra·di·an

 (stĭ-rā′dē-ən)
n. Abbr. sr
A unit of measure equal to the solid angle subtended at the center of a sphere by an area on the surface of the sphere that is equal to the radius squared. The total solid angle of a sphere is 4π steradians.

steradian

(stəˈreɪdɪən)
n
(Units) an SI unit of solid angle; the angle that, having its vertex in the centre of a sphere, cuts off an area of the surface of the sphere equal to the square of the length of the radius. Symbol: sr
[C19: from stereo- + radian]
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.steradian - the unit of solid angle adopted under the Systeme International d'Unites
angular unit - a unit of measurement for angles
sphere - a three-dimensional closed surface such that every point on the surface is equidistant from the center
Translations
stéradian
References in periodicals archive ?
Spectral photon flux measurements, in the range from 350 to 1050nm at 1nm intervals were carried out by means of a portable spectro radiometer (Field SpecPro[R]VNIR, ASD, USA) which was equipped with a remote cosine receptor (2[pi] steradian field of view) located at 50cm above the ground.
Here, the luminosity is per steradian in a specified (rest frame) energy bandpass (50-300 keV), averaged over 256 ms.
Radiance was quantified in photons per second per centimeter squared per steradian [24].
BLI signals were evaluated by drawing uniformly sized ROIs throughout the whole experiment and indicated in units of photons per square centimeter per second per steradian [13].
So a candela is the luminous intensity from a source of 1/683 watt per steradian. If you don't know what a steradian is, don't feel bad.
Defense Meteorological Satellite Program's (DMSP's) Operational Linescan System (OLS) light at night data in nanowatts per centimeter squared per steradian (B).
The optical output of this highly efficient emitter is 720 milliwatts (mW) at a current of 1 amp, with a radiant intensity of 1,000 milliwatts per steradian (mW/sr).
energies W = 10.5,11.05, and 11.5 GeV, where "nb/sr" in the vertical axis represents nanobarn per steradian. Here "total" denotes the differential cross section including contributions from both the signal and the background.
Planck constant 6.626070040 x [10.sup.-34] kilogram kg [m.sup.2]/s Speed of light 299,792,458 m/s meter in a vacuum Elementary 1.6021766208 x [10.sup.-19] ampere charge ampere seconds Boltzmann 1.38064852 x [10.sup.-23] kelvin constant kg [m.sup.2] ([s.sup.2] kelvin) Avogadro 6.022140857 x [10.sup.23]/ mole; used with constant mole [R.sub.[infinity]] to measure h, then define kg Rydberg 10,973,731.568508/m used with [N.sub.A] to constant measure h, then define kg Hyperfine 9,192,631,770/s second splitting of cesium Luminous 683 candela steradian candela efficacy [s.sup.3]/(kg [m.sup.2]) Fine-structure 1/137.035999139 none, but its value is constant related to the other constants
If a light source emits one candela of luminous intensity uniformly across a solid angle of one steradian, the total luminous flux emitted into that angle is one lumen.
Intensity 0.14 W/Steradian 8 Effective Angle 3.33 Steradian 9 E(theta), Mag.