TITLE:   GCN CIRCULAR
NUMBER:  28703
SUBJECT: GRB 201020A: Assy optical observations
DATE:    20/10/20 17:50:28 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

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

We observed the filed of GRB 201020A  (Ambrosi   et al., GCN 28696) with 
AZT-20 telescope of Assy-Turgen observatory starting on (UT) Oct. 20 
(Ut) 14:00:44 (UT)   in  r'-filter.  We clearly detect optical afterglow 
(Ambrosi   et al., GCN 28696;   Adachi et al., GCN 28697; Fu  et al., 
GCN 28701).

Preliminary photometry of the afterglow is following

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

2020-10-20 14:00:44  0.36688  r'(AB) 70*60    19.70 0.03   23.8

The photometry is based on the nearby stars of PanSTARRS-PS1 catalog.
SDSS-DR12_id        r
J172452.73+312623.9 18.459
J172455.96+312344.8 18.057
J172452.57+312302.1 17.618
J172456.76+312315.5 16.876