apostilb
Top
(′ap·ə′stilb)
(optics) A luminance unit equal to one ten-thousandth of a lambert. Also known as blandel.
Top
[Etymology: Gk: ‘away’ + ‘glitter’] (blondel) luminance, irradiance. Symbol asb. Metric-m.k.s. The name for a point on a diffuser, identically candela·steradian per square metre, = cd·sr·m-2. (There is no corresponding specially named unit in the SI, but the lux for illuminence is basically the same as the apostilb.) For a perfect diffuser, 1 asb corresponds to the emission of 1/π cd·m-2 = 0.3183~ cd·m-2. The corresponding c.g.s. unit was the lambert, = 104 asb.
A unit of luminance equal to (1/π) candela per square meter.
Post a question - any question - to the WikiAnswers community:
Copyrights:
McGraw-Hill Science & Technology Dictionary
McGraw-Hill Dictionary of Scientific and Technical Terms. Copyright © 2003, 1994, 1989, 1984, 1978, 1976, 1974 by McGraw-Hill Companies, Inc. All rights reserved.
Read more
Oxford Dictionary of Units & Measures
A Dictionary of Weights, Measures, and Units. Copyright © Donald Fenna 2002, 2004. All rights reserved.
Read more