TITLE: GCN GRB OBSERVATION REPORT NUMBER: 1758 SUBJECT: GRB 021211: CTIO observations DATE: 02/12/15 13:26:17 GMT FROM: Andrew Levan at U.of Leicester Andrew Levan (U. Leicester/STScI), Andrew Fruchter (STScI), Doug Welch (McMaster), Chris Palma (Penn State), Bryan Henderson (U. Washington), Michael Siegel and Ingunn Burud (STScI) report for a larger collaboration: The optical afterglow of GRB 021211 was imaged with the CTIO 4m telescope and Mosaic imager on the 12th Dec beginning 06:15UT and 13th Dec at 06:11UT. On 12th Dec, 1440s were obtained in both R and I. On 13th Dec 2880s were obtained in R only. Each observation consisted of several shorter, dithered observations. The afterglow is clearly visible in both epochs. Using a 1" aperture we measure magnitudes in the first epoch of R=22.8, I=22.5 and in the second epoch of R=23.1, where photometry has been calibrated using the calibration of Henden (GCN 1753). The host galaxy is a clearly visible extension to the north-east of the OT. Subtraction of a point source from the position of the optical transient on its host indicates that the brightest point source present was fainter than R=23.2 at the time of the first observations (t=19 hours), and R=23.6 at t=43 hours. Implying that the host galaxy is brighter than R=24. An image of the field, showing the OT and host galaxy on the night of Dec 12th can be found at http://www.stsci.edu/~fruchter/GRB/021211/ctio/host.jpg