Cygnus X-1

[Mike]

Cygnus X-1 Songfacts

Cygnus X-1 (often abbreviated to Cyg X-1) is an X-ray source in the constellation Cygnus, and considered to be a black hole. It is a high-mass X-ray binary, with the optical counterpart (HDE 226868) being a variable 8.9 magnitude star (visible with good binoculars in good observing conditions) at right ascension 19 h 56.5 min and declination of 35 deg 4 min (for 1950 epoch).

Tom Bolton identified Cygnus X-1 as a black hole in 1971 using the facilities of the David Dunlap Observatory at the University of Toronto.