TITLE: GCN CIRCULAR NUMBER: 35394 SUBJECT: GRB 231216A: Osservatorio Astronomico Nastro Verde upper limit DATE: 23/12/17 20:06:20 GMT FROM: Nello Ruocco at Osservatorio Nastro Verde - Sorrento (Naples) - Italy - MPC Code C82 <osservatorionastroverde@gmail.com> 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: We image the field of GRB 231216A detected by Swift Burst Alert Telescope (BAT)(trigger 1202749) 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 20:15 UT of 2023/12/16, after 1,40 hours after the GRB trigger, with principal telescope SC 0.35 f/10 with focal reduced + CCD Sbig ST10 XME I took 20 image of 60 sec each. All images are unfiltered, calibrated with masterdark and masterflat,stacked with Tycho Tracker software We have not detected any clearly visible sources, up to 19.5th magnitude in a sky with light clouds and gusts of wind. Start T0+ End T0+ Rlim 20:15:25 UT 20:36:38 UT 19.5 We did not found any optical counterpart in the error box of the XRTcandidate. T. Sbarrato et al. GCN 35378 Magnitudes were estimated with the Gaia DR2 cat. and are not corrected for galactic dust extinction. The message may be cited. View this GCN Circular online at https://gcn.nasa.gov/circulars/35394. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...