TITLE:   GCN CIRCULAR
NUMBER:  34996
SUBJECT: GRB 231110A: Terskol Zeiss-2000 optical upper limit
DATE:    23/11/12 10:50:05 GMT
FROM:    Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>

N. Pankov (IKI, HSE), I. Sokolov (INASAN, KIAM), A. Buslaeva (INASAN), A. Pozanenko (IKI),  S. Belkin (IKI, HSE)  report on behalf of GRB IKI FuN:

We observed the  Swift GRB 231110A (D'Elia et al., GCN #34977) with Zeiss-2000  telescope of Terskol observatory starting on 2023-11-10 (UTC) 23:25:16. We do not detect any object within Source #2 of XRT probable afterglow (Beardmore et al., GCN 34986). This is cosnistent with non-detection in other observations (Lipunov et al., GCN 34978; Sun et al., GCN 34979; Sun et al., GCN 34985; Moskvitin et al., GCN 34987; Gompertz et al., GCN 34988).  Preliminary photometry of the field is following.

Date       UT start  t-T0     Filter Exp.  OT   Err. UL.  Telescope
                     (mid, days)      (s)
2023-11-10 23:25:16  0.08729  R    28*120  R n/d n/d 22.4 Zeiss-2000

The photometry is based on the nearby USNO-B1.0 stars.