brightness

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brightness

(1) The luminous intensity of a light source, defined as candles/cm2.
(2) The intensity of reflection of light, measured in lamberts (one lambert equals 1 lumen/cm2).

brightness

(brīt′nĕs)
1. The perceived brilliance of an image, e.g., its clarity, how light it is (rather than how dark it looks), and the intensity of the light that it emits.
2. In imaging technology, e.g., radiology, the luminous intensity, measured in candelas, of a display monitor's visible emissions. Such brightness is solely a function of the monitor and is not related to the magnitude of exposure of the image receptor.

brightness 

Attribute of visual sensation according to which an area appears to emit more or less light. Syn. luminosity. Note 1: In British recommended practice, the term brightness is now reserved to describe brightness of colour (i.e. the opposite of dullness) as used in the dyeing industry. Note 2: This attribute is the psychosensorial correlate, or nearly so, of the photometric quantity luminance (CIE).
Brightness Acuity Tester (BAT) See glare tester.
brightness constancy See brightness constancy.
brightness enhancement See Brücke-Bartley effect.
References in periodicals archive ?
The apparent brightness temperature of the terrain [T.sub.g] consists of the radiated energy and the sky temperature.
All this information enabled astronomers to link the stars' distances with their apparent brightnesses to calculate their intrinsic brightnesses, and also measure their surface temperatures (or, at least, their spectral types).
After a summer interlude when ISON was lost in the Sun's glare, its apparent brightness at recovery in August 2013 further suggested that it might be too small and faint to survive its coming encounter with the Sun.
If that is so, they can be used to determine cosmic distances by the simple optical law that the apparent brightness of such a standard candle is its intrinsic brightness divided by the square of the distance.
This would be a boon to anyone using one of SBIG's self-guiding cameras and shooting through filters that reduce the apparent brightness of a guide star.
Changes in the apparent brightness of a comet's nucleus need not be due only to the formation of the coma, whose growth gives the nucleus a larger reflective surface.
Clusters (both open and globular) give us a way to circumvent the distance problem because the stars all lie at roughly the same distance from Earth, allowing us to use apparent brightness as a surrogate for luminosity.
By measuring the period and apparent brightness of a Cepheid, astronomers could easily calculate its distance.
The apparent brightness of Uranus depends on its distances from the Sun and Earth, so any study of a possible variation in Uranus's intrinsic brightness needs to take into account these changing parameters.
Combining this known intrinsic brightness with the newly established distance, and accounting for interstellar absorption, astronomers estimate that the supernova peaked with an apparent brightness between magnitude -7.9 and -7.1.
During the planet's July 2001 apparition, for instance, Curtis Roelle of New Windsor, Maryland, observed that as Mars drew closer to Earth and the planet's apparent brightness increased, Mars's color "changed from ruddy to orange and finally turned an almost golden color."
My 10-inch scope at 115x still displays both galaxies together, and while this scope adds only to the apparent brightness of NGC 5908, the view of NGC 5905 is much improved.