TITLE: GCN CIRCULAR NUMBER: 42275 SUBJECT: GRB 251013C: Calapai Observatory, Massa S. Giorgio (Messina), optical observation DATE: 25/10/14 23:48:43 GMT FROM: Giovanni Calapai at Calapai Astronomical Observatory, Massa S. Giorgio, Messina, Italy <giovannicalapai@tiscali.it> Giovanni Calapai at Calapai Astronomical Observatory, Massa S. Giorgio, (Messina) Italy Member of: GRB/UAI Gamma Ray Burst Section of Unione Astrofili Italiani. Report: We observed the field of GRB 251013C detected by SVOM (Rakotondrainibe et al., GCN 42222) with the 11 inches Schmidt-Cassegrain (Celestron 11) telescope F/D=6,3. The observations were started at 2025-10-13 19:01:08 UT (approximately 1.36 hours after burst) stacking 40 sets of unfiltered CCD image. The observations were carried out with clear skies and good visibility conditions. The OT was detected at the following position: RA (J2000.0) 23h 03m 20.56s Decl. (J2000.0) -00° 12' 37.00" We report our photometry analysis: HJD Exposure CR Mag Err ------------------------------------------- 2460962.295312 8x60s 15.56 0.01 2460962.301088 8x60s 15.75 0.01 2460962.306863 8x60s 15.97 0.01 2460962.312627 8x60s 16.09 0.01 2460962.318414 8x60s 16.16 0.01 2460962.324190 8x60s 16.20 0.01 2460962.329954 8x60s 16.27 0.01 2460962.335718 8x60s 16.41 0.01 2460962.341481 8x60s 16.53 0.01 2460962.347245 8x60s 16.61 0.01 2460962.353009 8x60s 16.68 0.01 2460962.358773 8x60s 16.69 0.01 2460962.364537 8x60s 16.72 0.01 2460962.370301 8x60s 16.80 0.01 2460962.376065 8x60s 16.80 0.01 2460962.381840 8x60s 16.90 0.01 2460962.387627 8x60s 16.91 0.01 2460962.393403 8x60s 17.02 0.01 2460962.399178 8x60s 17.02 0.01 2460962.404954 8x60s 17.17 0.01 2460962.410729 8x60s 17.17 0.02 2460962.416505 8x60s 17.22 0.02 2460962.422280 8x60s 17.23 0.02 2460962.428067 8x60s 17.31 0.02 2460962.433843 8x60s 17.35 0.02 2460962.439618 8x60s 17.38 0.02 2460962.445382 8x60s 17.44 0.02 2460962.451157 8x60s 17.43 0.02 2460962.456933 8x60s 17.58 0.03 2460962.462697 8x60s 17.56 0.03 2460962.468461 8x60s 17.70 0.03 2460962.474224 8x60s 17.62 0.03 2460962.479618 8x60s 17.72 0.03 2460962.485903 8x60s 17.75 0.03 2460962.491678 8x60s 17.86 0.04 2460962.497454 8x60s 18.02 0.05 2460962.503241 8x60s 18.03 0.05 2460962.509016 8x60s 17.97 0.05 2460962.514792 8x60s 17.99 0.05 2460962.521667 11x60s 18.06 0.05 Magnitude was calibrated with the nearby PanSTARRS stars converted using Lupton (2005) equations. No correction for galactic dust extinction was applied. Our observations are consistent with other already reported Perez-Garcia et al. (GCN circ. 42225), Konno et al. (GCN circ. 42226), Martin-Carrillo et al. (GCN circ. 42227), Masi (GCN circ. 42228), Palmerio et al. (GCN circ. 42229), Moskvitin et al. (GCN circ. 42230), Gompertz et al. (GCN circ. 42231), Watson et al. (GCN circ. 42241), López-Cámara et al. (GCN circ. 42242), Zhang et al. (GCN circ. 42248), Brosio et al. (GCN circ. 42251), Quintana-Ansaldo et al. (GCN circ. 42254), Maksut et al. (GCN circ. 42256), Quadri et al.(GCN 42262), Adami et al.(GCN 42266), Peretto et al.(GCN 42267), Ruocco et al. (GCN 42269). The message may be cited. View this GCN Circular online at https://gcn.nasa.gov/circulars/42275. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...