TITLE: GCN CIRCULAR NUMBER: 6277 SUBJECT: GRB 070411: Magellan/IMACS photometry DATE: 07/04/12 03:16:51 GMT FROM: Edo Berger at Carnegie Obs E. Berger (Carnegie) and H. Yee (Toronto) report: "We obtained a 180 sec image in I-band with the IMACS instrument on the Magellan/Baade telescope on 2007 Apr 11.99 UT (3.55 hr after the burst). We detect the afterglow with I=20.3 mag relative to the USNO-B star located at RA=07:09:17.9453, DEC=+01:04:09.210 with I=17.8 mag."