TITLE: GCN CIRCULAR NUMBER: 5927 SUBJECT: GRB 061217: ROTSE-III Optical Limits DATE: 06/12/17 04:34:39 GMT FROM: Brad Schaefer at LSU B. E. Schaefer (Louisiana State) reports on behalf of the ROTSE collaboration: ROTSE-IIId, located at the Turkish National Observatory at Bakirlitepe, Turkey, responded to GRB 061217 (Swift trigger 251634), producing images beginning 6.3 s after the GCN notice time. An automated response took the first image at 03:40:26.3 UT, 18.1 s after the burst, under excellent conditions. We took 10 5-sec, 10 20-sec and 20 60-sec eposures. These unfiltered images are calibrated relative to USNO A2.0 (R). The last few images have substantial background from twilight, and so our imaging has now stopped in Turkey. Comparison to the DSS (second epoch) reveals no new sources within the 3-sigma error circle, for both single images and coadding into sets of 10; the field is not crowded. Individual images have limiting magnitudes ranging from 15.3-16.9; we set the following specific limits. start UT end UT t_exp(s) mlim t_start-tGRB(s) Coadd? -------------------------------------------------------------------- 03:40:26.3 03:40:31.3 5 15.3 18.1 N 03:40:26.3 03:42:34.5 128 17.2 18.1 Y 03:58:53.0 04:10:09.5 676 17.3 1124.8 Y