Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Webpage for Optical Technology Division: SIRCUS Facility



Sally Bruce, Steven W. Brown, Keith R. Lykke


Spectral irradiance and Radiance Calibrations with Uniform Sources (SIRCUS) is a reference calibration facility that transfers detector based spectral irradiance scales derived from the High Accuracy Cryogenic Radiometer, to broadband filtered detector packages, to transfer-standard spectral irradiance detectors, and to instruments that measure spectral radiance. This facility will be used to realize NIST's illuminance, luminous intensity, radiance temperature, color temperature, and sprectal radiance scales, improving their uncertainties and self-consistency.
Electronic Publication


radiance calibrations, spectral irradiance, uniform sources


Bruce, S. , Brown, S. and Lykke, K. (2002), Webpage for Optical Technology Division: SIRCUS Facility, Electronic Publication, [online], None (Accessed July 13, 2024)


If you have any questions about this publication or are having problems accessing it, please contact

Created April 30, 2002, Updated October 12, 2021