TITLE:   GCN CIRCULAR
NUMBER:  37055
SUBJECT: GRB 240805B: BTA optical afterglow candidate
DATE:    24/08/06 00:45:23 GMT
FROM:    Moskvitin Alexander at SAO RAS <mosk@sao.ru>

A. Moskvitin, D. Oparin, A Vinokurov (SAO RAS), N. Pankov (HSE, IKI)
and A. Pozanenko (IKI) report:

We observed the field of the GRB 240805B (Williams et al., GCN 37043)
with the BTA 6-meter telescope of SAO RAS equipped with the focal
reducer Scorpio-I. We obtained 7 x 120 + 30 sec images on August 5,
2024-08-05T19:31:44 -- 2024-08-05T20:10:44 (t_mid - T0 = 8.372 hours).

Within the enhanced XRT error circle (Goad et al., GCN 37053) close
to its edge we detected a single source with the coordinates (J2000):
R. A. = 16:56:51.20
Dec. = +18:19:11.7 +/- 0".5
and brightness of R = 21.62 +/- 0.04 (calibrated against nearby SDSS
stars, magnitudes converted with Lupton 2005 equations)
and not corrected for Galactic extinction.

This source is located near SDSS object J165651.21+181914.0
but significantly brighter, thus it may be GRB OT.