GCN Circular 29651
M. Jelinek, J. Strobl, S. Trcka, R. Hudec, C. Polasek (ASU CAS Ondrejov) report: We observed the position of the Integral trigger 9073 (GRB 210312.87 or B) with the D50 robotic telescope of the Astronomical Institute Ondrejov, near Prague, Czech Republic. We performed a series of 10s and 20s unfiltered exposures starting 23.8 s after the trigger. In the first images we detect a rapidly fading object not present in the DSS catalogue at 10:23:15.312 +76:52:06.96 J2000. The preliminary magnitude of the object in the earliest images was R~18m.