UBV system(redirected from UBV photometric system)
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UBV system[¦yü‚bē¦vē ‚sis·təm]
A system of stellar magnitudes in which an object's apparent magnitude is measured at three wavelengths, labeled U, at 360 nanometers; B, at 420 nanometers; and V, at 540 nanometers; and is characterized by the color indices B-V and U-B, which are both defined to be 0 for a star of spectral type A0. Also known as Johnson-Morgan system.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.