A large number of the Seyfert galaxies presently known were identified in the low-dispersion spectroscopic survey of Markarian and his colleagues at the Byurakan Observatory in Armenia (see Lipovetsky, Markarian, and Stepanian 1987). The Byurakan survey was done with an objective prism on a 1-m telescope, at a dispersion of ~ 1800 Å mm-1. These spectra were used to identify UV-excess objects. Huchra (1977) estimates that about 11% of the objects in the Markarian catalogs are Seyfert galaxies, ~ 2% are Galactic stars (mostly very hot white dwarfs), another ~ 2% are QSOs and BL Lac objects, and the rest are galaxies which are rather blue for their morphological type (blue compact dwarf galaxies and starburst galaxies).
Adapted from B.M. Peterson An Introduction to Active Galactic Nuclei, Cambridge University Press, (1997)