Precession and nutation in SS 433.

The data base on the kinematical characteristics of SS 433 is examined. The object simultaneously displays high red- and blue-shifts, which have been attributed to two collimated, antiparallel jets undergoing a precessional motion aproximately every 163 days. Nightly variations in the jets' emission lines are supposedly caused by intensity and profile changes, different ejection events, and the presence of multiple lines. The precessional period, judging from X-ray and radio data, regularly oscillated about a mean value. The jets may issue from a collapsed object surrounded by a thick accretion disk orbited by a normal star. Further modeling and data are required to delineate the scales and energetics of the SS 433 components.