TITLE: GCN GRB OBSERVATION REPORT NUMBER: 1425 SUBJECT: GRB020604, optical observations DATE: 02/06/11 21:55:25 GMT FROM: Arne A. Henden at USNO/USRA A. Henden (USRA/USNO) reports on behalf of the USNO GRB team: We imaged an 11x11 arcmin field centered at the coordinates for the IPN burst GRB020604 (Hurley et al., GCN 1417) with the USNOFS 1.0-m telescope on 020608.295 (3.7d after the burst), and again on 020611.276. Coadded images give a plate limit of V=21.5. No new object was seen within the CCD field of view, which does not contain the entire 160 square arcmin error box. This field is at galactic coordinates 349.07, +13.12 and so is cluttered with stars, with few extragalactic objects seen. One object, present on the digitized plates available from the USNO Pixel Server (http://www.nofs.navy.mil), exhibits large variability. Located at 16:27:38.28 -29:47:38.0 J2000 with astrometric error under 100mas, the object was V=18.9 on 020608 and V=21.4 on 020611.