TITLE: GCN GRB OBSERVATION REPORT NUMBER: 1925 SUBJECT: GRB030226, BVRc observations DATE: 03/03/05 15:19:08 GMT FROM: Vladimir Sokolov at SAO RAS T. Fatkhullin, V. Komarova, V. Sokolov, A. Cherepashchuk, k. Postnov report for the larger GOSH collaboration: The field of the GRB 030226 optical transient (Fox et al., GCN #1879) was observed with CCD-photometer at the 1-m (Zeiss-1000) and SCORPIO at the 6-m telescopes of SAO RAS during three nights. Data from the 6-m telescope were obtained during time of the scheduled program "Search for optical emission of nearby pulsars" (P.I. V.G. Kurt). The weather conditions were slightly variable with cirruses and seeing of 2.5-3.0 arcsec in the first night, 2.5 arcsec seeing in the second one and 1.4 arcsec seeing in the third one. The B, V, Rc filters were used. Photometric calibration was performed using secondary standard stars of Henden et al., GCN #1916. The results of our photometry are presented below: Telescope | Mean Date, UT | Tot. exp. | Filter | Mag. -------------------------------------------------------------- Zeiss-1000 | 27.96 Feb. | 2400s | V | 22.07 +/- 0.19 Zeiss-1000 | 27.92 Feb. | 2000s | Rc | 21.75 +/- 0.18 6-m | 28.99 Feb. | 1200s | B | 24.64 +/- 0.21 6-m | 01.00 Mar. | 1350s | V | 23.66 +/- 0.16 6-m | 28.99 Feb. | 720s | Rc | 22.96 +/- 0.12 6-m | 01.94 Mar. | 1200s | V | 23.89 +/- 0.12 6-m | 01.92 Mar. | 1200s | Rc | 23.39 +/- 0.09 In the images obtained at the last night we clearly detect an extended object (R=22.9) 2.5 arsec South-East from optical transient (OT) position. Thus, the results of our aperture photometry of the OT may be affected by this object. We are planning to recalibrate the data provided additional realiable secondary standards are available. We thank V.G. Kurt for sharing observational time and O. Spiridonova for kind assistance in the Zeiss-1000 observations. This message is citeable.