TITLE: GCN CIRCULAR NUMBER: 35433 SUBJECT: GRB 231210B: BOOTES-7 optical upper limit DATE: 23/12/29 07:22:12 GMT FROM: Alberto Castro-Tirado at Inst.de Astro. de Andalucia <ajct@iaa.es> A. J. Castro-Tirado, Y.-D. Hu, E. Fernandez-Garcia, M.D. Caballero-Garcia, R. Sanchez-Ramirez, I. Perez-Garcia, S.-Y. Wu, S. Guziy  (IAA-CSIC Granada), C. Perez del Pulgar, A. Castellon, A. Reina (Univ. de Malaga), B.-B. Zhang (Nanjing Univ.) and A. Maury (Space, San Pedro de Atacama), report: Following the detection of GRB 231210B by Swift (Page et al., GCNC 35314) and Konus-Wind (Frederiks et al. GCNC 35359), the 0.6m BOOTES-7 robotic telescope at San Pedro de Atacama (Chile) pointed to the burst position on Dec. 21 at 01:32 UT (i.e. ~10.2 days after trigger). Images were gathered in different optical bands. In the co-added r-band image (8 x 300 s, SDSS-r filter), the optical afterglow reported by MASTER (Lipunov et al. GCNC 35313), UVOT (Page et al., GCNC 35314), LCOGT (Pérez-Fournon et al. GCNC 35316), VLT (Saccardi et al. GCNC 35317) and MeerLICHT (de Wet et al. GCNC 35323) is not detected within the enhanced Swift/XRT position (Beardmore et al. GCNC 35318) down to 21.0 mag, which is consistent with the REM results (Ferro et al. GCNC 35333). Regarding the source reported at the Greenhill Observatory (Siellez et al. GCNC 35406), we cannot clearly identify it since it is blended with a nearby and brighter star 0.4" away. In any case, we notice that this object is present on the DESI catalog and it is far from the enhanced Swift/XRT position and therefore unrelated to GRB 231210B. BOOTES-7 is the last observatory completing the BOOTES Global Network of robotic telescopes in all the continents (Castro-Tirado 2023, Nat. Astron. 7, 1136), 25 years after the first astronomical station was deployed in south Spain. We thank the staff at San Pedro de Atacama Celestial Explorations observatory for their excellent support. View this GCN Circular online at https://gcn.nasa.gov/circulars/35433. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...