TITLE:   GCN CIRCULAR
NUMBER:  27240
SUBJECT: GRB 200224A: Mondy optical upper limit
DATE:    20/02/27 16:28:46 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

S. Belkin (IKI), A. Pozanenko (IKI), E. Klunko (ISTP), E. Mazaeva (IKI), 
A. Volnova (IKI) report on behalf of IKI-GRB-FuN:

We observed the field of GRB 200224A (Ukwatta  et al., GCN 27173; Fermi 
GBM team GCN 27174) with AZT-33IK telescope of Sayan observatory (Mondy) 
starting on Feb. 26 (UT) 17:24:49. We did not detect the optical 
afterglow (Sota et al., GCN 27176; Stecklum et al., GCN 27177; Marshall 
et al., GCN 27182; Becerra et al., GCN 27182; Fernandez et al., GCN 
27222). Preliminary photometry of the field is following.

Date UT start,      t-T0    Filter Exp.   OT UL(3sigma)
                     (mid, days)    (s)
2020-02-26 17:24:49 2.60348 R      29*120 n/d 22.6

Photometry is based on the USNO-B1.0 nearby stars.