- Author
- Treado, S. J. | Remmert, W. E. | Bean, J. W.
- Title
- Sky Luminance and Direct Beam Illuminance.
- Coporate
- National Bureau of Standards, Gaithersburg, MD
- Report
- NBSIR 85-3251, March 1986, 51 p.
- Distribution
- Available from National Technical Information Service
- Keywords
- sky; luminance; daylighting; irradiance; illuminance; measurement; beams (radiation)
- Abstract
- Measurement of sky illuminance, sky luminance, direct beam illuminance and direct beam irradiance are analyzed and discussed. The database consisted of an annual set of integrated hourly measurements made at the National Bureau of Standards, Gaithersburg, Maryland. The relationship between diffuse sky illuminance and luminance of selected portions of the sky dome is examined. Measured sky luminances are compared to luminance calculated using equations for three standard sky types-clear, partly cloudy and overcast. The results indicate that the luminance distribution of actual skies varies considerably from the standard skies.