TITLE:   GCN CIRCULAR
NUMBER:  26914
SUBJECT: GRB 200127A: Mondy optical upper limit
DATE:    20/01/28 10:35:13 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 200127A (Moss et al., GCN 26895) with 
AZT-33IK telescope of Sayan observatory (Mondy) starting on Jan. 27
(UT) 21:48:01. We do not detect any optical object within Enhanced 
Swift-XRT position (Evans et al., GCN 26902) in agreement with 
non-detection of an afterglow (Liu et al., GCN 26904; Fynbo et al., GCN 
26913). Preliminary photometry of the field is following.

Date UT start       t-T0,   Filter Exp.,  OT  Err  UL(3sigma)
                     (days)         (s)
2020-01-27 21:48:01 0.30868 R      21*120 n/d n/d  22.8

Photometry is based on the USNO-B1.0 nearby stars.
USNO-B1.0    R2
1349-0340555 18.02
1349-0340544 17.39