TITLE:   GCN CIRCULAR
NUMBER:  30701
SUBJECT: GRB 210822A: Abbey Ridge Observatory optical afterglow observation
DATE:    21/08/24 06:49:06 GMT
FROM:    Filipp Dmitrievich Romanov at Amateur astronomer  <filipp.romanov.27.04.1997@gmail.com>

Filipp D. Romanov (Russia) and David J. Lane (Saint Mary's University,
Canada) report:

Filipp Romanov observed optical afterglow of GRB 210822A (Page et al.,
GCN Circ. 30677) remotely using 0.355-m f/6.2 Schmidt-Cassegrain
telescope of Abbey Ridge Observatory (it is owned by Dave Lane) in
Canada, on 2021-08-23.

Four images (with exposures: 720, 720, 600 and 720 seconds) were
obtained with Cousins R filter from 00:54:39 to 02:17:30 UTC. Faint
(SNR = 5) optical afterglow (with UVOT position) is visible in the
stacked image (mid time =  01:36:04 UTC, that is 16.296 hours after
the trigger). Romanov measured its magnitude comparing to transformed
(using formula Rc=r’-0.22 from Dymock & Miles, 2009) r' magnitudes of
nearby stars from Pan-STARRS DR1 catalogue (Chambers et al., 2016).
The measured magnitude = 20.1 +/- 0.3. Magnitude was not corrected for
Galactic extinction.

Stacked image available here:
http://abbeyridgeobservatory.ca/images/grb210822a.jpg