[T.sub.sky] = equivalent blackbody temperature
of sky (K or R)
Conversely Wien's law tells us that the wavelength at which one works limits the range of blackbody temperatures
- and thus the types of objects - one will be able to detect.
Without acknowledging the strict requirements involved in setting a blackbody temperature
[2-4], they made recourse to the laws of thermal radiation, obtaining a temperature of 3.5 [+ or-] 1.0K .
An optical pyrometer measures the blackbody temperature
by sensing radiation from one end of the furnace.
Its photopigments and color processing could be designed for perception of blackbody temperature
rather than of surface reflectance.
Because the former angle is larger than the latter one, geometrical optics suggests that the total power detected depends only on the blackbody temperature
and a geometrical factor related to the pinhole aperture, detector optics, and relative separation, because the detector pupil is overfilled.
After the blackbody temperature
was stabilized at the set value, the radiometer and the heat flux sensor were placed in front of the blackbody exit at stations A, B and C.
NIST uses a variable temperature blackbody as a standard of spectral radiance to provide its spectral radiance and irradiance calibration services (148, 149); the blackbody temperature
is also determined using a gold-point blackbody and spectral radiance ratios.
In the affected channels of GOES--8 and GOES--10 sounders, NIST measurements done at the on-orbit operational temperature conditions disagreed with SRFs in use by NOAA and also were found to be more consistent with on-orbit radiance observations at known blackbody temperatures
, thus explaining the possible discrepancy (6).