TITLE: GCN CIRCULAR NUMBER: 27605 SUBJECT: GRB 200412B: continued Terskol optical observations DATE: 20/04/19 13:50:32 GMT FROM: Alexei Pozanenko at IKI, Moscow S. Belkin (IKI), A. Pozanenko (IKI), A.V. Shein (INASAN), I.A. Izvekova (ICAMER NASU), E. Mazaeva (IKI), A. Volnova (IKI) report on behalf of GRB IKI FuN: We observed the field of GRB 200412B (Fermi GBM team, GCN 27547; Mailyan et al., GCN 27558; see also Burgess et al., GCN 27548; Longo et al., GCN 27557; Page et al., GCN 27561; Gupta et al., GCN 27563; Zheng et al., GCN 27565) with Zeiss-2000 of Mt.Terskol observatory. We marginally detected the afterglow of GRB 200412B (Lipunov et al., GCNs 27555, 27556; see also e.g. Kumar et al., GCN 27564; Belkin et al., GCN 27566, Stecklum et al., GCN 27567, Moskvitin GCN 27570; Xin et al., GCN 27571). Preliminary photometry of the afterglow is following. Date UT start t-T0 Filter OT Err. UL Observatory (mid, days) 2020-04-18 19:52:22 6.47687 43*120 R 23.6 0.3 23.6 Terskol Z-2000 The photometry is based on nearby USNO-B1.0 stars. The update light curve can be found at http://grb.rssi.ru/GRB200412B/GRB200412B_LC.png