TITLE:   GCN CIRCULAR
NUMBER:  35226
SUBJECT: GRB 231129C: iTelescope likely optical afterglow AT 2023yph discovery
DATE:    23/11/30 04:57:40 GMT
FROM:    Filipp Dmitrievich Romanov at Amateur astronomer <filipp.romanov.27.04.1997@gmail.com>

I observed the field of GRB 231129C (Fermi GBM Team, GCN Circ. 35217)
near the MAXI (GCN Circ. 35223) sky region using remote telescope T72
(0.51-m f/6.8 Corrected Dall-Kirkham + CCD) of iTelescope.Net in Deep
Sky Chile at Rio Hurtado Valley, Chile. 9 images (with exposures 300
seconds, BINx1) were obtained with Ic filter with midtime 02:27 UT. I
detected an uncataloged source with position 00 49 17.780 -81 29 45.83
and measured its brightness near +18 mag. Magnitude was not corrected
for Galactic extinction. I am guessing this is an optical afterglow of
GRB 231129C. Now it is AT 2023yph
https://www.wis-tns.org/object/2023yph
F. D. Romanov (AAVSO).