TITLE: GCN CIRCULAR NUMBER: 8699 SUBJECT: GRB 081222: Faulkes Telescope South observations DATE: 08/12/22 13:51:17 GMT FROM: Cristiano Guidorzi at Ferrara U,Italy A. Melandri (Liverpool JMU), C. Guidorzi (U. Ferrara), D. Carter (Liverpool JMU) report on behalf of a larger collaboration: On 2008 December 22 (10:17:46 UT) we began observing the field of GRB 081222 (Grupe et al. GCN Circ. 8691) with the Faulkes Telescope South. Observations consisted of two sequences of 6x300s exposures acquired using the SDSS-i and SDSS-r filters, respectively. We clearly detect the optical afterglow reported by REM (Covino et al. GCN Circ. 8692) and GROND (Updike et al. GCN Circ. 8693), with the following magnitudes: Telescope Filter T_mid[hr] Exposure[s] Mag -------------------------------------------------------------- FTS SDSS-i 5.47 2x300 20.45 +/- 0.25 FTS SDSS-r 6.01 2x300 21.34 +/- 0.30 -------------------------------------------------------------- The calibration was performed using the R2 and I magnitudes of several USNOB-1 catalogue field objects. Uncertainties include the different zero points of the USNOB-1 stars. Compared with the value reported by GROND (Updike et al. GCN Circ. 8693), we estimate a power-law index between the two epochs of about 1.1 .