TITLE:   GCN CIRCULAR
NUMBER:  34487
SUBJECT: GRB 230818A: KGO RC-25 optical observations
DATE:    23/08/19 10:06:00 GMT
FROM:    Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>

N. Pankov (HSE, IKI)  A. V. Samokhvalov (citizen scientist, Surgut), 
A. Pozanenko (IKI), S. Belkin (IKI, HSE)   report on behalf of GRB IKI FuN:

We observed the field of GRB 230818A (Swift: Tohuvavohu et al., GCN 34479; Fermi:  GBM team, GCN 34478) with 25cm telescope of KGO observatory. Observation started on 2023-08-18 23:42:15, i.e. 14.5 minutes after GRB trigger. The series consist of images with an exposure of 600 s in R-filter. WE clearly detect the afterglow (Lipunov et al., GCN 34476; Gompertz et al., GCN  34480; Moskvitin et al., GCN 34483; Malesani  et al., GCN 34485; Siegel et al., GCN 34486). Preliminary photometry of  images is following

Date UT-start       Exptime Filter t-T0      OT     Err    UL
                    sec            days
2023-08-18 23:42:15 1*600   R      0.013667  18.7   0.2    19.3
2023-08-18 23:52:24 6*600   R      0.038080  19.8   0.3    19.9

Ref.stars
PanSTARRS-DR1
RA Dec r i R(Lupton transformation)
19:03:22.0694 +40:55:31.814 14.1600 14.0074 13.97
19:04:17.2714 +40:50:28.744 14.8986 14.7352 14.71