Charles Thomas Bolton (April 15, 1943 – c. February 4, 2021)[1] was an American-Canadian astronomer who was one of the first in his field to present strong evidence of the existence of a stellar-mass black hole.
[2] In 1971, as a post-doctoral fellow and part-time faculty member studying binary systems at the Dunlap Observatory,[5][6] Bolton observed star HDE 226868 wobble as if it were orbiting around an invisible but massive companion emitting powerful X-rays,[2][7] independently of the work by Louise Webster and Paul Murdin, at the Royal Greenwich Observatory.
[8] Further analysis gave an estimate about the amount of mass needed for the gravitational pull, which proved to be too much for a neutron star.
After more observations confirmed the results, by 1973, the astronomical community generally recognized black hole Cygnus X-1, lying in the plane of the Milky Way galaxy at a galactic latitude of about 3 degrees.
[12][2] Bolton was instrumental in passing the first light-pollution regulation Canada, a 1995 bylaw to limit light pollution in the town Richmond Hill, home of the David Dunlap Observatory.