Fr.: scintillement, vacillement
Short term random variations either in amplitude or phase of a radio signal.
Jitter, may be variant of chitter "tremble, shiver," from M.E. chiteren "to twitter, chatter."
Jastojah, from jast and jah past and present stems of jahidan "to jump, leap, spring forward; to shake or tremble," from Mid.Pers. jastan, jahidan "to jump," figuratively "to happen, occur;" Av. yaēš-, yas- "to boil;" cf. Skt. yas-, yásyati "to boil, to heat; to make effort" + -o- euphonic infix, on the model of kandokâv, oftoxiz, and so on.
A mode of observation in which a series of short exposures are used to enhance the final image quality through appropriate data processing. The first exposure is assumed to be centered on the point of interest; the following ones are slightly offset from the first position with separations not larger than a reasonably small fraction of the detector size. The offsets should be optimally distributed on the sky in order to maximize the chances of being able to filter out the sky background.