Astronomical Scintillation
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Astronomical Scintillation
Any
scintillation phenomena, such as irregular
oscillatory motion, variation of intensity, and color fluctuation observed
in the light emanating from am extraterrestrial source; to be
distinguished from
terrestrial scintillation primarily
in that the light source for the latter lies somewhere within
the earth's atmosphere. Also called stellar scintillation .
See
seeing.
Astronomical scintillation is typically strongest for celestial
objects lying at large zenith distances and is not easily observed
by eye for objects whose zenith distances are under 30°.
Nonperiodic vibratory motions of stellar images with frequencies
of the order of 1 to 10 cycles per second create a troublesome
problem of seeing in astronomical work. The size of the schlieren
producing vibratory scintillations has been estimated to be of
the order of centimeters, and chromatic scintillations of celestial
objects appear to be produced by parcels whose dimensions are
of the order of decimeters or, perhaps, meters. Hence, astronomical
scintillation is primarily a consequence of the high-frequency,
short-wavelength type of atmospheric turbulence.
References
This article is based on NASA's Dictionary of Technical Terms for Aerospace Use
