TITLE:   GCN CIRCULAR
NUMBER:  36121
SUBJECT: GRB 240415A: Mondy optical transient detection (photometry correction in GCN 36118 )
DATE:    24/04/15 20:42:11 GMT
FROM:    Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>

N. Pankov (HSE, IKI), A. Pozanenko (IKI), E. Klunko (ISTP), A. Moskvitin (SAO RAS), S. Belkin (IKI) report on behalf of GRB-IKI-FuN:

We report correction to the GCN 36118 (Pankov et al.) and additional photometry in subsequent epochs.  
Preliminary photometry of the optical transient is following:

Date       UT_start  MJD           Filter Exp.  OT    err  UL(3sigma)
                    (mid, days)           (s)
2024-04-15 14:33:22  60415.627345  R     30*120 19.9 0.1 21.8
2024-04-15 16:13:49  60415.697104  R     30*120 20.5 0.1 21.9
2024-04-15 17:20:02  60415.732668  R     15*120 20.9 0.1 21.9

The magnitudes were calibrated using nearby USNO-B1.0 stars.