TITLE: GCN CIRCULAR NUMBER: 34573 SUBJECT: Swift J1727.8-1613 (GRB 230824A): Montarrenti Observatory photometric observations DATE: 23/08/27 14:57:12 GMT FROM: Simone Leonini at Montarrenti Observatory (Siena, Italy) S. Leonini, M. Conti, P. Rosi, L.M. Tinjaca Ramirez (Montarrenti Observatory, Siena, Italy) report: We observed the field of Swift J1727.8-1613 (GRB 230824A) (Page et al., GCN 34537; Odeh et al., GCN 34543; Dutton et al., GCN 34556; Odeh et al., GCN 34561; Quadri et al., GCN 34562; Lopresti, GCN 34566; Pavoni & Moretti, GCN 34570) with the remote controlled 0.53m Ritchey-Chretien telescope + U47 detector at Montarrenti Observatory (Siena, Italy, IAU code C88) in 2 epochs, starting on Aug 24.78994 (5 hours after trigger) and Aug. 26.79422 2023 (53 hours after trigger) with multiple exposures in V, Rc and Ic band. The OT was detected at the following position: RA (J2000.0) 17h 27m 43.32s +/-0.2 Dec. (J2000.0) -16° 12' 18.60" +/-0.2 Photometry was obtained using nearby PanSTARRS stars as follows: ============================== Obs. midtime UT Filter Mag. Err. ============================== 2460181.2962325 V 13.45 0.002 2460181.3049015 V 13.48 0.002 2460181.3127082 V 13.50 0.002 2460181.3205208 V 13.50 0.002 2460181.3305952 V 13.47 0.002 2460183.3018576 V 12.54 0.003 2460183.3062470 V 12.52 0.003 2460183.3143382 V 12.48 0.004 2460183.3208796 V 12.50 0.004 ----------------------------------------------- 2460181.2973320 R 13.39 0.001 2460181.3053240 R 13.42 0.001 2460181.3131307 R 13.42 0.001 2460181.3213754 R 13.44 0.001 2460181.3315657 R 13.39 0.001 2460183.2976407 R 12.43 0.002 2460183.3047650 R 12.43 0.002 2460183.3089728 R 12.41 0.002 2460183.3200694 R 12.44 0.002 ----------------------------------------------- 2460181.2940451 I 13.29 0.002 2460181.3031443 I 13.28 0.002 2460181.3109548 I 13.26 0.002 2460181.3187615 I 13.22 0.002 2460181.3265489 I 13.26 0.001 2460181.3336487 I 13.26 0.001 2460183.2980439 I 12.28 0.003 2460183.3052912 I 12.26 0.003 2460183.3164382 I 12.27 0.003 2460183.3204745 I 12.26 0.003 ----------------------------------------------- Magnitudes were converted using Lupton 2005 equations and are not corrected for galactic dust extinction. Further observations are planned.