GCN Circular 9276
M. Im, Y. Jeon, W. Park, I. Lee (CEOU/Seoul National Univ), Y.-B. Jeon (KASI) and Y. Urata (NCU) on behalf of EAFON team. We observed GRB090426 (Cummings et al. GCN 9254) in R using the 1.0m telescope at Mt. Lemmon (Arizona, US) operated by the Korea Astronomy Space Science Institute. The R-band imaging started at 2009 April 27, 04:43:19 UT. The mid-point of the R-band obseravation is April 27, 05:06:47 UT (16.3 hrs after the burst). From a stacked image of 6 frames (3 min exp. each), the afterglow is barely visible in the image where the R-band magnitude limit is R = 21.7 at 5-sigma. Therefore, we set an upper limit of the R-band magnitude to be R ~ 21.7, which should be close to the afterglow brightness. The photometry was calibrated against USNO-B1 stars in the vicinity of GRB. We thank the LOAO operator, I. Baek for her assistance for this observation.