[citation needed] This Type II-P supernova was discovered by Japanese astronomer Kōichi Itagaki on 31 July 2004.

At the time of its discovery, its apparent brightness was 11.2 visual magnitude; the discovery occurred after the supernova had reached its peak magnitude.

[1][2] The supernova's progenitor is a star in a young, compact star cluster in the galaxy NGC 2403, in Camelopardalis.

The cluster had been cataloged as the 96th object in a list of luminous stars and clusters by Allan Sandage in 1984; the progenitor is therefore commonly referred to as Sandage 96.

This cluster is easily visible in a Kitt Peak National Observatory image and appears starlike.