TITLE: GCN CIRCULAR NUMBER: 37666 SUBJECT: GRB 241002A: 1.5m OSN optical upper limit DATE: 24/10/02 05:43:41 GMT FROM: Alberto Castro-Tirado at Inst.de Astro. de Andalucia A. Sota, S. Guziy, I. Perez-Garcia, S.-Y. Wu, M. D. Caballero-Garcia, R. Sanchez-Ramirez, A. J. Castro-Tirado (IAA-CSIC) and Y.-D. Hu (INAF-OAB), on behalf of a larger collaboration, report: Following the detection of GRB 241002A by Swift (Caputo et al. GCNC 37662), we triggered the 1.5m telescope of the Observatiorio Sierra Nevada (OSN) near Granada, Spain. Observations began on Oct 2 at 03:47 UT (~ 2.95 h post burst). No optical afterglow is detected at the coadded I-band image (4 x 600 s) within the enhanced Swift/XRT position (Osborne et al. GCNC 37665) down to 22.0 mag. We thank the staff at OSN for their excellent support.