TITLE: GCN CIRCULAR NUMBER: 38372 SUBJECT: GRB 241128A: LCO optical detection DATE: 24/11/28 21:48:43 GMT FROM: luca.izzo@inaf.it L. Izzo (INAF-OACn and DARK/NBI), and D. B. Malesani (DAWN/NBI and Radboud Univ.) report: We observed the field of GRB 241128A (Brivio et al., GCN #38367) with the Sinistro instrument mounted on the 1-m telescope of the LCO network, located at the Teide Observatory, Spain. Observations started on 2024 November 28 at 19:04 UT (2.83 hr after the GRB trigger). We obtained a series of 3x300 s images in the SDSS-r filter. The afterglow reported by Hu et al. (GCN #38371; see also Page et al., GCN #38368) is well detected in our images. We measure a preliminary magnitude of r = 19.24 +/- 0.07 mag (AB), calibrated against nearby stars from the Pan-STARRS catalog. This project has received funding from the European Union's Horizon 2020 research and innovation program under grant agreement No 101004719.