C/2009 R1

C/2009 R1 ( McNaught ) is the 51st comet named McNaught.

He was discovered on September 9, 2009 by British- Australian astronomer Robert H. McNaught at the Uppsala Southern Schmidt Telescope at Siding Spring Observatory in Australia. Its perihelion C/2009 R1 went through on July 3, 2010. In June 2010, the comet reached a brightness of about 5 mag and was in low light areas with the naked eye visible. The green coma at its core can be explained by the presence of cyanogen and carbon ( C2), the blue gleam in his tail by carbon monoxide and carbon dioxide ions.