TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3377 SUBJECT: GRB 050505: Keck I-band Magnitude DATE: 05/05/07 23:02:43 GMT FROM: S. Bradley Cenko at Caltech S. Bradley Cenko, Chuck Steidel, Naveen Reddy, and Derek B. Fox report on behalf of the Caltech-NRAO-Carnegie GRB Collaboration: We have further analyzed the I band images of the afterglow of GRB 050505 reported in GCN 3366. Using the USNO-B1 star located at RA: 09:27:06.5667, Dec: +30:17:18.750 (I = 18.85) as a reference, we find the following magnitude for the afterglow: UT Time UT Date Time Since Burst (hr) Magnitude ------------------------------------------------------------------------ 5:45:47 May 6 6.4 20.66 +/- 0.1