TITLE: GCN CIRCULAR NUMBER: 35014 SUBJECT: GRB231111A: MDM 2.4m Hiltner Telescope Observation DATE: 23/11/13 16:57:13 GMT FROM: Tianrui Sun at Purple Mountain Obs,CAS Tian-Rui Sun, Tian-Ci Zheng, Hui-Yang Mao, Jiang-Tao Li report: Following the detection of GRB 231111A by SWIFT (Melandri et al., GCN 34981; Osborne et al., GCN 34991;GCN 34995), MASTER (Lipunov et al., GCN 34980; GCN 34983), Nanshan/HMT (Jiang et al., GCN 34982), GIT (Kumar et al., GCN 34984), YAHPT (Sun et al., GCN 34985), GECAM (Zhang et al., GCN 34990; GCN 34993), Mondy (Pankov et al., GCN 34994), Terskol Zeiss-2000 (Pankov et al., GCN 34996), Nastro Verde (Dainotti et al., GCN 34997), GMG (Mao et al., GCN 34999; GCN 35001), Mephisto (Sun et al., GCN 35002), Leavitt (Moretti et al., GCN 35003), NUTTelA-TAO (Komesh et al., GCN 35004) and Xinglong-2.16m (Jiang et al., GCN 35012), we conducted observations using the MDM 2.4m Hiltner telescope with the clear filter. This observation began from 2023-11-12T01:44:16.415, about 11.4 hours after the burst. The PSF photometry results are shown as : ---------------------------------------------------- UT exposure filter mag magerr ------------------------------------------------------ 2023-11-12T01:44:16.415 600 Clear 20.7669 +/- 0.0622 2023-11-13T01:35:18.404 600 Clear 22.1815 +/- 0.0697 ------------------------------------------------------ We used the GAIA-DR3 catalogue (G mag) as the magnitude reference for calibration.