TITLE:   GCN CIRCULAR
NUMBER:  35672
SUBJECT: GRB 240204A: Montarrenti Observatory optical observations
DATE:    24/02/04 23:54:13 GMT
FROM:    Simone Leonini at Montarrenti Observatory (Siena, Italy) <s.leonini@iol.it>

S. Leonini, M. Conti, P. Rosi, L.M. Tinjaca Ramirez, L. Bellizzi (Montarrenti Observatory, Siena, Italy, part of UAI/SSV-GRB section), M.G. Dainotti (National Astronomical Observatory of Japan), Y. Niino (Tokyo University, Institute of Astronomy), K. Kalinowski (Aarhus University, Department of Physics and Astronomy) and B. De Simone (Universita' degli Studi Di Salerno) report:

We observed the field of GRB 240204A (Swift triggered on the Fermi/GBM, GCN 35664; Cenko et al., GCN 35666; Pozanenko et al., GCN 35670) with the automated and remoted 0.53m Ritchey-Chretien telescope at Montarrenti Observatory (Siena, Italy, IAU code C88).

The observations were started under good weather conditions at 2024-02-04 18:58:44 UT (approximately 4 hours after burst) stacking 30x40s Rc-band CCD images.

The OT was detected at the following position:

RA      (J2000.0)  06h 56m 43.39s +/-0.11 
Decl. (J2000.0) +01° 01'   38.5"    +/-0.14

Preliminary photometry was obtained using nearby PanSTARRS stars as follows: 

         MJD         Filter   Mag.       Err.
60345.30597    Rc     21.02  +/-0.21

Magnitudes were converted using Lupton (2005) equations and were not corrected for galactic dust extinction.