This Seyfert and ultraluminous infrared galaxy is commonly known as Mrk 273. It contains a double nucleus (1" separation)) with a single, spectacular tidal tail 130,000 light-years long and a 'ring' of star formation. Much of the activity in the system is associated with the northern nucleus where there is a considerable amount of young star formation.

400/500mm - 17.5" (6/18/93): faint, very small, very compact (core viewed) but hint of extension (tail?) to S. A mag 13 star lies 1' N. Located 4.5' W of mag 6.5 SAO 28878 which detracts from viewing. Forms a pair with MCG +09-23-002 3' WSW.

600/800mm - 24" (6/21/20): at 375x; fairly faint, small, oval 3:2 N-S, ~18"x12". Occasionally I seemed to glimpse an extension (tidal tail) to the south, though it was too faint to estimate a length and difficult to confirm. MCG +09-23-002 lies 3.4' SW and MCG +09-23-003 is 6' N. Located 4.3' W of mag 6.5 HD 11999.

900/1200mm - 82" (5/5/19, McDonald Observatory): at 613x; the main body of Mrk 273 appeared bright, moderately large, elongated 5:3 ~N-S. It was strongly concentrated with a very bright elongated core that increased to a nearly stellar nucleus. A subtle bulge was noticed on the SW edge. This is probably a merged interacting companion [on the SDSS the "bulge" has a blue color]. A very easy, large narrow tidal tail extended south as a very long "spike", perhaps 40"x6"! A mag 16.4 star is 0.6' NE. MCG +09-23-002, a thin edge-on, lies 3.4' SW.

Notes by Steve Gottlieb