Skip to main content
Testing. You are viewing the public testing version of GCN. For the production version, go to
New Announcement Feature, Code of Conduct, Circular Revisions. See news and announcements

GCN Circular 30492

GRB 210722A: D50 optical detection
2021-07-24T08:40:09Z (3 years ago)
Martin Jelinek at Astro.Inst-AVCR,Ondrejov <>
M. Jelinek, J. Strobl, R. Hudec, C. Polasek (ASU CAS Ondrejov) report:

We observed the position of the bright GRB 210722A (D'Avanzo et al., GCN
30475; Page et a., GCN 30483; Barthelmy et al. GCN 30489; and Wood, GCN
30490) with the D50 telescope of the Astronomical Institute Ondrejov, near
Prague, Czech Republic. We performed a set of 35x 60s exposures in SDSS-i'
filter on July 24 from 1:20 to 2:01 UT.

The optical afterglow (Zhu et al., GCN 30476; Pankov et al., GCN 30478 &
30488; Kumar et al., GCN 30481; Butler et al., GCN 30484; and Thoene et
al., GCN 30487) is weakly detected in the overall combined image with the
exposure mean time 28.9h after trigger. The Atlas-calibrated magnitude of
the object is i' = 19.8 +/- 0.4.
Looking for U.S. government information and services? Visit