TITLE:   GCN CIRCULAR
NUMBER:  29954
SUBJECT: ZTF21aayokph (AT2021lfa): Mondy and Koshka observatory optical observations
DATE:    21/05/06 20:42:41 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

N. Pankov (HSE, IKI), S. Belkin (IKI), E. Klunko (ISTP), A. Novichonok 
(Petrozavodsk State University, KIAM),  A. Pozanenko (IKI),  A. 
Zhornichenko (KIAM) report  on behalf of GRB IKI FuN:

We observed the field of ZTF21aayokph (AT2021lfa) (Yao et al., GCN 
29938) with AZT-33IK telescope of Sayan observatory (Mondy) and  and 
Zeiss-1000 telescope of Koshka observatory (INASAN).

We clearly 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) 
in Mondy observatory and marginally detect it in Koshka observatory.

Preliminary photometry of the optical transient is following

Date       UT start     Filter Exp.   OT   Err.  UL(3sigma) Telescope
                              (s)

2021-05-05 14:57:10     R      25*120  20.70 0.07  22.7  AZT-33IK
2021-05-05 17:56:56     R      38*120  21.5  0.4   21.3  Zeiss-1000


The photometry is based on the nearby USNO-B1.0 star
USNO-B1.0_id R2
0884-0227886 14.13