This SN was discovered by LOSS (IAUC 8395) on August 25, 2004, and was absent on August 21, 2004, so discovered shortly after explosion.
The host galaxy IC 5090 is at z=0.031155 (NED).
(IAUC 8404) says this is a type II, but based on our data, Doug says maybe more like Ib/c. In either case, a core-collapse event. Further observations by Hamuy and collaborators indicate type II with lots of Helium (IAUC 8409). A nice Keck spectrum shows this is indeed a peculiar type II SN.