TITLE:   GCN CIRCULAR
NUMBER:  30064
SUBJECT: ZTF21aayokph (AT2021lfa): continued Assy optical observations
DATE:    21/05/21 06:58:41 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

N. Pankov (HSE, IKI),  S. Belkin (IKI), V. Kim (FAI, Pulkovo 
Observatory), M. Krugov (FAI), A. Pozanenko (IKI), report on behalf of 
GRB IKI FuN:

We observed the field of  ZTF21aayokph (AT2021lfa) (Yao et al., GCN 
29938) with AZT-20 telescope of Assy-Turgen observatory on 2021-05-17 
and  2021-05-18.

We still detect the optical transient (Yao et al., GCN 29938; Watson et 
al., GCN 29940; Butler et al., GCN 29941; Yao et  al., GCN 29945; Fu et 
al., GCN 29948; Kim  et al., GCN 29950; O'Connor  et al., GCN 29952; Ho 
et al., GCN 29953; Pankov et al., GCN 29954; Lipunov et al., GCN 29959; 
Pankov et al., GCN 29964).

Preliminary photometry of the optical transient  is following

Date       UT start  t-T0       Exp.    Filter  OT    Err.  UL(3sigma)
                    (mid, days)  (s)

2021-05-17 16:19:12  n/a       200*60   r'      23.60  0.28   23.9
2021-05-18 15:52:05  n/a       230*60   r'      23.67  0.29   24.0

The photometry is based on the nearby SDSS-DR12 stars.