TITLE: GCN GRB OBSERVATION REPORT NUMBER: 1765 SUBJECT: GRB021211: APO optical observations DATE: 02/12/17 23:23:11 GMT FROM: Don Lamb at U.Chicago D. Q. Lamb, M. C. Nysewander, D. E. Reichart, J. C. Barentine, C. Laws, D. G. York, and R. J. McMillan report, We have calibrated our i* image of the optical transient and host galaxy of GRB021211 (Crewe et al., GCN 1734), taken with the ARC 3.5-meter telescope at APO beginning at 09:19 UT on December 12 (Lamb et al., GCN 1744). Using the photometric calibration reported by A. Henden (GCN 1753) and a 1" aperture, we measure i* = 23.0 +/- 0.20 mag for the optical afterglow. This value may be subject to some systematic error because of the presence of the host galaxy, which is visible as an extension to the northeast of the afterglow (Lamb et al., GCN 1744; McLeod et al., GCN 1750; Levan et al. GCN 1758; Caldwell et al., GCN 1759). Conservative upper limits on the brightness of the host galaxy are i* > 24.1 mag (1 sigma), > 23.4 mag (2 sigma), and > 23.0 mag (3 sigma). Second epoch observations of the GRB021211 field are planned that will enable us to refine these values. An i* image of the GRB021211 field, showing the optical afterglow and the host galaxy on the night of Dec 12th can be found at http://astro.uchicago.edu/home/web/lamb/grb021211/apo/ot_and_host.jpg This message may be cited.