I observed the optical afterglow of the extremely bright GRB 221009A = Swift J1913.1+1946 remotely using telescope T24 (0.61-m f/6.5 reflector + CCD) of iTelescope.Net in Sierra Remote Observatory (Auberry, California, USA) on 2022-10-11.

Two images (exposures 300 seconds, BINx1) were obtained with Ic filter, midtime of the stacked image is 06:12:42 UT (1d16h02m after the trigger).

I clearly detected the afterglow and measured (aperture photometry, without deblending) following magnitude: 17.1 Ic +/- 0.2 from comparison to transformed (from Lupton 2005) magnitudes of nearby stars from the Pan-STARRS DR1 catalogue (Chambers et al., 2016).

GRB221009A 20221010.2588 17.1I RFD 0.2

Magnitude was not corrected for the Galactic extinction.

Stacked image available here: https://www.flickr.com/photos/filipp-romanov/52419866941