TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2225 SUBJECT: GRB 030329: Optical limit (contemporaneous imaging) DATE: 03/05/12 03:55:03 GMT FROM: Ken ichi Torii at RIKEN Y. Okamoto (NIFTY-Serve Space Forum), K. Ohnishi (Nagano National College of Technology), and K. Torii (RIKEN) report: The sky area of the GRB 030329 (Vanderspek, et al., GCN 1997) was contemporaneously imaged with the Yatsugatake Camera between 2003 March 29 10:00 UT (97 minutes before burst) and 14:00 UT. The Yatsugatake Camera is an ultra wide field (85 x 70 deg) video camera (focal length 3.5mm, f/1.4 lens equipped with Sony XC-75) placed at an altitude of 1000m in Yatsugatake, Japan. Images are output in NTSC format after 8-s (on-chip) integrations, stored to frame memory (MSJ SS-10), and recorded to timelapse video tape. The camera has built-in infrared-cut filter while no additional filter is used. By now, we have digitized and inspected the data between 10 minutes before and after the burst and created running mean images of four consecutive frames. In these images, a neighboring V=5.1 star (41 LMi) is clearly detected while no transient stellar object brighter than 41 LMi is seen at the position of the optical afterglow (Peterson and Price, GCN 1985; Torii, GCN 1986). We therefore derive preliminary upper limit of 5.1 mag for an optical transient associated with this GRB on continuous 32-s time bins between 2003 March 29 11:27 UT and 11:47 UT. Further analysis is in progress.