The quality of an imaging system which is characterized by → isoplanatism.
Izobirâh, from izo-, → iso-, + birâh "a devious path; a wanderer, who deviates, errs."
Fr.: angle isoplanatique
The angle in which the → point spread function of the atmosphere/telescope system is space invariant. Because of the presence of → turbulence in high layers of the atmosphere, this angle is extremely small, often only a few seconds of arc at visible wavelengths. See also → aplanatism.
pac-e izobirâh, teke-ye ~
Fr.: tache isoplanatique
The spatial region where the variation of the → point spread function of an imaging system is considered negligible.