TITLE: GCN GRB OBSERVATION REPORT NUMBER: 1577 SUBJECT: GRB 021004, SPM optical observations DATE: 02/10/05 11:03:32 GMT FROM: Sergej Zharikov at OAN IA UNAM S. Zharikov, R. Vazquez, G. Benitez (OAN IA UNAM, Mexico), S. del Rio (INAOE, Mexico) report: We have observed the optical afterglow of GRB021004 (HETE Trigger 2380) as reported by Fox et al. (GCN 1564) with the 84-cm and 1.5m telescopes of SPM observatory in Mexico between 05:20:00 UT and 09:50 UT on Oct. 5 2002. Using the R-band photometric zero-point USNO star at RA=00:26:58.713, DEC=+18:56:56.61 (GCN #1564) R=15.64 from Weidinger et. al. (GCN 1573), we find preliminary object magnitudes: UT R 05:28:19 19.23 06:47:00 19.29 07:02:00 19.33 09:42:24 19.35 This message may be cited.