TITLE: GCN CIRCULAR NUMBER: 34577 SUBJECT: Swift J1727.8-1613 (GRB 230824A): Osservatorio Astronomico "Nastro Verde" optical observations DATE: 23/08/27 19:24:18 GMT FROM: Nello Ruocco at Osservatorio Nastro Verde - Sorrento (Naples) - Italy - MPC Code C82 Nello Ruocco at Osservatorio Nastro Verde - Sorrento (Naples) - Italy in a large collaboration with: M.G. Dainotti (National Astronomical Observatory of Japan), Y. Niino (Tokyo University, Institute of Astronomy), K. Kalinowski (Aarhus University, Department of Physics and Astronomy), B. De Simone (Universita' degli Studi Di Salerno) report: Following the Swift trigger no. 1186959 (GCN 34537), we pointed at the coordinates RA(J2000)=17h 27m 46s: Dec(J2000)=-16d 12' 53" and started our observations with telescope of Nastro Verde Observatory - Sorrento (Naples), Italy. Member of: AAVSO - American Association of Variable Star Observers. UAI/SSV - Unione Astrofili Italiani/sezione stelle variabili. AstroCampania Associazione. The observations started at 19:23 UT of 2023/08/24, after about 5,25 hours after the GRB trigger, at the end of twilight with clear skies, with principal telescope SC 0.35 f/10 with focal reduced + CCD Sbig ST10 XME I took 9 image of 120 sec each in fotometric V and 13 in Rc . All images, calibrated with masterdark and masterflat have been measured with Maxim DL software We have detected a clear visible source at the enhanced position reported by Swift Burst Alert Telescope (BAT) (Page et al., GCN 34537 ) and by other telescopes ( Jamie A. Kennea (PSU) et al GCN 34540., S. Dichiara (PSU) et al GCN 34542, 34547, 34554,34555., Mohammad Odeh et al GCN 34543, 34561., H. Negoro (Nihon U). et al GCN 34544., Brendan O'Connor et al GCN 34549.,Dylan Dutton et al GCN 34556., T. M. Parsotan et al GCN 34557., U.Quadri et al GCN 34562., Claudio Lopresti et al GCN 34566., S. Leonini et al GCN 34573) at following position RA (J2000.0) 17:27:43.32 Dec (J2000.0) -16:12:19 with the following photometry: JD Mag Filter 2460181.317 13.69 V 2460181.32 13.74 V 2460181.323 13.66 V 2460181.326 13.59 V 2460181.329 13.63 V 2460181.332 13.55 V 2460181.335 13.54 V 2460181.338 13.62 V 2460181.341 13.55 V JD Mag Filter 2460181.309 13.49 Rc 2460181.31 13.51 Rc 2460181.312 13.54 Rc 2460181.313 13.45 Rc 2460181.315 13.47 Rc 2460181.318 13.48 Rc 2460181.321 13.50 Rc 2460181.324 13.52 Rc 2460181.33 13.45 Rc 2460181.333 13.46 Rc 2460181.336 13.50 Rc 2460181.339 13.50 Rc 2460181.342 13.50 Rc The magnitudes are calibrated with stars of the PanSTARRS catalog, espressed in AB system and are not corrected for the expected Galactic extinction. The peculiar transient ( detected by other observatories ) is confirmed in our observations. Further observations are encouraged.