PHOTOMETRY AND SPECTROPHOTOMETRY OF THE SEYFERT-GALAXY MRK-509 OVER 23 YEARS

In the time period from 1972-1993, the Seyfert 1 galaxy Mrk 509 showed large variations of its optical continuum and broad emission line flu xes. The broad H-beta and H-gamma emission lines have approximately th e same profiles, which retain their shape during flux variations. The relationship between the continuum and emission line fluxes varies wit h time. The spectral energy distribution of the variable continuum bas ed on UBVRI data has the form IgF(nu) approximate to -alpha lg nu, wit h the dereddened alpha = -0.60.