{
  "bibcode": "2022GCN.31431....1M",
  "body": "A. Moskvitin (SAO), on behalf of larger GRB follow-up team report:\n\nWe observed the field of GRB 220107A (The Fermi GBM team, GCN 31399;\nKunzweiler et al. GCN 31400; DeLaunay et al. GCN 31402; Suresh et al.,\nGCN 31408; Ridnaia et al., GCN 31429) with the SAO RAS 1-m telescope\nZeiss-1000 + CCD-photometer. Two series of images in Rc band\nwere obtained: the 1st under moderate weather conditions\nand the 2nd with relatively clear sky.\n\nThe OT (Hosokawa et al. GCN 31413; Siegel GCN 31415; Zhu et al.\nGCN 31416; Pankov et al., GCN 31419; Moskvitin et al., GCN 31422;\nCastro-Tirado et al., GCN 31423, Moskvitin & Medvedev, GCN 31426)\nis clearly visible in the stacked frames.  Preliminary photometry\nof the afterglow is as follows (based on nearby SDSS-DR12 stars\nmentioned in GCNs 31422, 31426).\n\nUT start -- UT end    T_mid-T0, d  Exp., s   R_mag +/- err   series\n\nJan. 10     Jan. 11\n23:22:13 -- 02:06:39  3.41592      23 x 300  21.69 +/- 0.10  1st\n\nJan. 11     Jan. 11\n02:49:39 -- 03:30:10  3.51694       8 x 300  22.03 +/- 0.09  2nd",
  "circularId": 31431,
  "createdOn": 1641877728000,
  "email": "mosk@sao.ru",
  "subject": "GRB 220107A: SAO RAS optical observations",
  "submitter": "Moskvitin Alexander at SAO RAS  <mosk@sao.ru>",
  "eventId": "GRB 220107A"
}