SN 2005ap was an extremely energetic type Ic supernova in the galaxy SDSS J130115.12+274327.5.

[2] It was discovered on 3 March 2005, on unfiltered optical images taken with the 0.45 m ROTSE-IIIb (Robotic Optical Transient Search Experiment) telescope, which is located at the McDonald Observatory in West Texas, by Robert Quimby, as part of the Texas Supernova Search that also discovered SN 2006gy.

[4] As it occurred 4.7 billion light years from Earth, it was not visible to the naked eye.

SN 2005ap was about 300 times brighter than normal for a type II supernova.

Quimby has suggested that the hypernova is of a new type distinct from the standard type II supernova, and his research group have identified five other supernovae similar to SN 2005ap and SCP 06F6, all of which were extremely bright and lacking in hydrogen.