{
  "body": "Claudio Lopresti (Gruppo Astronomia Digitale - GAD Observatory, La Spezia, Italy),\nin a large collaboration with:\nM.G. Dainotti (National Astronomical Observatory of Japan),\nY. Niino (Tokyo University, Institute of Astronomy),\nK. Kalinowski (Aarhus University, Department of Physics and Astronomy),\nB. De Simone (Universita' degli Studi Di Salerno)\nreport:\n\nI imaged the field of GRB 230812B (Lesage et al., GCN 34387;\nScotton et al., GCN 34392; Page, GCN 34394; Zheng & Filippenko, GCN 34395;\nLipunov et al., GCN 34396; Salgundi et al., GCN 34397; Ackley et al., GCN 34398;\nXiong et al., GCN 34401; Casentini et al., GCN 34002; Frederiks et al., GCN 34403;\nMao et al., GCN 34404; Odeh et al., GCN 34405; Moskvitin et al., GCN 34406)\ndetected by FERMI(trigger 713559497.049606 / 230812790)\nwith the GAD Observatory, La Spezia, Italy Italy.\n\nMember of:\nUAI/SSV - Unione Astrofili Italiani/sezione stelle variabili, GRB section\nGAD - Gruppo Astronomia Digitale\n\nThe observations started 48.02 hour after the FERMI trigger, At the end of twilight\nwith a Maksutov-Newton telescope D=180 mm F/D=4\n\nWeather conditions were good.\n\nWe co-added  series of 8 exposures of 60 sec each.\n\nStart T0+        End T0+          R lim\n3168 min       3178 min         19.6\n\nI did not detect any optical afterglow in the Swift/XRT (Page, GCN\nCirc. 34387) position. The magnitude limit is about 19.5 mag, compared\nto the magnitudes of nearby stars from the Gaia EDR3 Catalog\n\nMagnitudes were estimated with the Gaia EDR3 cat. and\nare not corrected for galactic dust extinction.\n\nReference:\nhttps://www.parcodellestelle.com/\n\nThe message may be cited. ",
  "eventId": "GRB 230812B",
  "submitter": "Claudio Lopresti <cl3lop@gmail.com>",
  "createdOn": 1692182295764,
  "subject": "GRB 230812B: GAD Observatory optical observations (upper limit)",
  "bibcode": "2023GCN.34445....1L",
  "circularId": 34445,
  "submittedHow": "email-legacy"
}