Abstract
Interstellar Scintillation (ISS) has been established as the cause of the random variations in compact radio radio sources on times of a day or less. This interpretation provides quantitative information on the structure of the inner regions of the Radio-Emitting Jets on scales down to 10 μarcsec, once the distance to the scattering region is known. In turn these imply Doppler factors 5-75, which are on the same order as derived from VLB interferometry.
