TITLE:   GCN CIRCULAR
NUMBER:  29240
SUBJECT: GRB 210102B: Assy optical observations
DATE:    21/01/04 18:06:38 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

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

We observed MAXI GRB 210102B (Guo et al., GCN 29223) with AZT-20 
telescope of Assy-Turgen observatory starting on  Jan. 03 (UT) 13:00:53. 
i.e.  ~1.6 days after trigger.  At the place of the only one of XRT 
candidates (Burrows  et al., GCN 29230) in the localization area of MAXI 
(Guo et al., GCN 29223) we clearly detect the optical object in 
coordinates (J2000) 23:35:15.88 -21:04:55.5 with uncertainness of 0.6 
arcsec in both coordinates.
Preliminary photometry of the object  is following

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

2021-01-03 13:00:53  1.19068  r'(AB)  75*60  22.2 0.2   23.0

The photometry is based on the stars of PanSTARRS-PS1
RA DEC r'
23:35:20.67802 -21:04:16.4688 19.656
23:35:47.99017 -21:11:53.6544 17.807

At this tome we cannot confirm variability of the source. We can suggest 
the object might  be related to GRB 210102B.