UBVRI and H-beta observations of 3C 390.3

A historical B-band light curve dating back to 1966 shows a large increase in brightness during 1970-1971, followed by a gradual decrease down to a minimum in 1982. During the 1995-2000 lapse the broad H{beta} emission and the continuum flux varied by a factor of ~3.

Two large amplitude outbursts, of different duration, in continuum and light were observed i.e.: in October 1994 a brighter flare that lasted ~1000 days and in July 1997 another one that lasted ~700 days were detected. The response time lag of the emission lines relative to flux changes of the continuum has been found to vary with time i.e. during 1995-1997 a lag of about 100 days is evident, while during 1998-1999 a double valued lag of ~100 days and ~35 days is present in our data.