{
  "createdOn": 1743626893359,
  "format": "text/plain",
  "circularId": 40013,
  "subject": "GRB 250331C: Calapai Observatory, Massa S. Giorgio (Messina), upper limit",
  "submitter": "Giovanni Calapai at Calapai Astronomical Observatory, Massa S. Giorgio, Messina, Italy <giovannicalapai@tiscali.it>",
  "body": "\nGiovanni Calapai at Calapai Astronomical Observatory, Massa S. Giorgio, (Messina) Italy \nMember of: GRB/UAI Gamma Ray Burst Section of Unione Astrofili Italiani. \n\nReport:\n\nWe imaged the field of GRB 250331C detected by Swift Burst Alert Telescope (BAT) (Cenko et al. GCN 39959),\nwith the 11 inches Schmidt-Cassegrain (Celestron 11) telescope F/D=6,3. \n\nThe observations were started at 2025-03-31 20:59 UT (approximately 16.37 hours after burst) stacking a set of unfiltered CCD image. The observations were made with modest sky conditions and the target low on the horizon. \n\nWe co-added 30 exposures of 60 sec each.\n\nStart T0+      End T0+     CR lim\n16.37 hour    16.92 hour    18.7\n\nWe did not found any optical counterpart in the error box of the XRTcandidate.\nEvans GCN 39960\n\nMagnitudes were estimated with the PanSTARRS cat. and \nare not corrected for galactic dust extinction.\n\nOur observations are consistent with other already reported Dornic et al. (GCN 39963), Lipunov et al. (GCN 39981), Siegel et al. (GCN 40003).\n\nThe message may be cited.",
  "eventId": "GRB 250331C",
  "bibcode": "2025GCN.40013....1C",
  "submittedHow": "web"
}