TITLE: GCN CIRCULAR NUMBER: 39370 SUBJECT: GRB 250217C: DDOTI Upper Limits on the Optical Afterglow DATE: 25/02/19 05:38:12 GMT FROM: Rosa L. Becerra at Tor Vergata, Roma <rosa.becerra@roma2.infn.it> Rosa L. Becerra (U Roma), Alan M. Watson (UNAM), Simone Dichiara (Penn State University), Eleonora Troja (U Roma), Camila Angulo Valdez (UNAM), Nat Butler (ASU), Tsvetelina Dimitrova (ASU), Alexander Kutyrev (GSFC/UMD), William H. Lee (UNAM), Océlotl López (UNAM), and Margarita Pereyra (UNAM) report: We observed the field of GRB 250217C detected by Fermi/GBM (Fermi GBM Team et al., GCN 39357), AstroSat CZTI (Tembhurnikar et al., GCN 39359), and IPN (Kozyrev et al., GCN 39365), with the DDOTI/OAN wide-field imager at the Observatorio Astronomico Nacional on Sierra San Pedro Martir (http://ddoti.astroscu.unam.mx) on the night of 2025-02-19 UTC. DDOTI observed the whole IPN error box reported by Kozyrev et al. (GCN 39365) from 03:31 UTC to 04:37 UTC (from T+27.6 to T+28.7 hours after the event) with a total exposure of 48 minutes, down to a 5-sigma limiting magnitude of w = 21.1. Comparing our observations to the USNO-B1 and PanSTARRS PS1 DR2 catalogues, we detect no uncatalogued sources within the observed field to our 5-sigma limit. We thank the staff of the Observatorio Astronómico Nacional in San Pedro Mártir. View this GCN Circular online at https://gcn.nasa.gov/circulars/39370. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...