GCN Circular 30228

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

Filipp Romanov observed optical afterglow of GRB 210610B (Page et al.,
GCN Circ. 30170
Not found
 
 
) remotely using telescopes: 0.61-m f/6.5 Corrected
Dall-Kirkham of Burke-Gaffney Observatory (BGO, Dave Lane is
Observatory Director) and 0.355-m f/6.2 Schmidt-Cassegrain of Abbey
Ridge Observatory (ARO, it is owned by D. Lane) on 2021-06-11.

Two images (with exposures 240 and 300 seconds) were obtained on BGO
with Sloan i' filter; on ARO were obtained two clear (unfiltered)
images (with exposures 840 and 900 seconds) and two images (with
exposures 900 and 840 seconds) with Cousins R filter.

F. Romanov measured following magnitudes of afterglow from comparison
to i' magnitudes of nearby stars from the SDSS Photometric Catalogue
DR12 (Alam et al., 2015) for BGO images and from r' magnitudes for ARO
unfiltered images; from comparison to R magnitudes of nearby stars
from USNO-A2.0 catalogue (Monet et al., 1998) for ARO Rc images:


UTC midtime
of exposure    T_mid-T0, h     Magnitude    Mag. error
-------------------------------------------------------
02:07:55       6.27            17.45  i'    0.12
02:09:15       6.30            17.64  r'    0.03
02:14:20       6.38            17.61  i'    0.08
02:27:12       6.60            17.36  Rc    0.05
02:44:54       6.89            17.78  r'    0.08
03:03:24       7.20            17.50  Rc    0.08
-------------------------------------------------------


Magnitudes were not corrected for Galactic extinction.


Images available here:

http://www.ap.smu.ca/~bgo/sm/id.php?app=0&id=15162

http://aro.abbeyridgeobservatory.ca/sm/id.php?app=0&id=3325

http://www.ap.smu.ca/~bgo/sm/id.php?app=0&id=15163

http://aro.abbeyridgeobservatory.ca/sm/id.php?app=0&id=3326

http://aro.abbeyridgeobservatory.ca/sm/id.php?app=0&id=3327

http://aro.abbeyridgeobservatory.ca/sm/id.php?app=0&id=3328