The analysis and comparative tests of tracing systems on a transmitting TV lube-dissector have been made. Their application for measuring "stellar image tremor" in a local plane of astronomical telescopes lias been considered. To perform astro-climatic researches, the digital tracing systems have been used. The center of gravity of a stellar image was separated out by effective suppression of "scintillation" background which is characteristic lor light propagation in a turbulent atmosphere. It was shown, based on the results of experimental measurements of "stellar image tremor" over a plane underlying surface and model calculation of telescope limiting resolution that the spatial resolution and errors of a digital tracing system weakly depend on the light-source intensity.