steradian

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].

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).

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.