GCN Circular 34483
Subject
GRB 230818A: SAO RAS Zeiss-1000 observations
Date
2023-08-19T03:12:38Z (a year ago)
From
Moskvitin Alexander at SAO RAS <mosk@sao.ru>
Via
legacy email
A. S. Moskvitin, D. V. Oparin, V. S. Shergin and
V. V. Komarov (SAO RAS), report on behalf of the GRB follow-up team.
We observed the field of GRB 230818A (Fermi GBM team, 34478;
Tohuvavohu et al., GCN 34479) with the 1-m telescope of SAO RAS
Zeiss-1000 equipped with the CCD photometer. We started observations
on August 18, 23:32:18 UT (~5 minutes after the trigger) and obtained
multiple images in BVRcIc bands (principally in Rc).
We clearly detected the OT (Lipunov et al., GCNs 34476, 34477,
34481, 34482; Gompertz et al., GCN 34480) in our individual
frames with the coordinates
R. A. (J2000) = 19:03:33.11
Decl. (J2000) = +40:53:49.2 (+/- 0".5)
and the following brightness:
UT_start exp, s t_mid-T0, h Rmag +/- err
23:32:18 60 0.0872 17.79 +/- 0.06
23:34:00 60 0.1156 18.07 +/- 0.06
23:45:06 120 0.3089 19.18 +/- 0.08
23:57:27 120 0.5147 19.68 +/- 0.10
00:29:01 300 1.0658 20.52 +/- 0.13
00:45:26 2 x 300 1.39333 20.48 +/- 0.09
This preliminary photometry is based on nearby USNO-B1 stars (R2 mag),
the magnitude is not corrected for MW extinction.