June 3, 2011: As an update to AAVSO Special Notice #241 (http://www.aavso.org/aavso-special-notice-241), the supernova in M51 has been designated SN 2011dh. Discovery, classification, and observation information have been published in IAU CBET 2736 (Daniel W. E. Green, ed.).
Coordinates: 13:30:05.08 +47:10:11.2 (J2000.0)
Coordinates source is Silverman et al., ATEL 3398
Observations should be submitted to the AAVSO International Database using the name SN 2011dh.