Please note that this is a scanned copy of a paper originally published in 1993, so the text is not as clear as in documents created as pdf files.

People like daylight in buildings, and daylight can make a building more energy-efficient. This paper draws on measurements made at BRE to illustrate the changing nature of light from the sky. It gives advice on how to measure daylight under the real sky or an artificial sky. 4 pages.