{
  "circularId": 37049,
  "createdOn": 1722878539222,
  "submittedHow": "email-legacy",
  "bibcode": "2024GCN.37049....1M",
  "eventId": "EP240801a",
  "subject": "EP240801a: BTA BVRI photometry",
  "submitter": "Moskvitin Alexander at SAO RAS <mosk@sao.ru>",
  "body": "A. Moskvitin, D. Oparin (SAO RAS), N. Pankov (HSE, IKI), A. Pozanenko (IKI)\nreport:\n\nWe observed the field of the fast X-ray transient EP240801a\n(Zhou et al., GCN 36997) with the BTA 6-meter telescope\nof SAO RAS equipped with the focal reducer Scoprio-I on August, 3\n(t_mid - T0 = 2.629 days) and August, 4 (t_mid - T0 = 3.485 days).\n\nThe OT (Fu et al., GCN 36998; Li et al., GCN 36999; Zheng et al.,\nGCN 37000; Aryan et al., GCN 37002; An et al., GCN 37004;\nPerez-Fournon et al., GCN 37007; Malesani et al., GCN 37008;\nZhu et al., GCN 37010; Moskvitin et al., GCNs 37012, 37017;\nQuirola-Vasquez et al., GCN 37013; Moretti et al., GCN 37014;\nTurpin et al., GCN 37015; Pankov et al., GCNs 37016, 37040) is clearly\ndetected in stacked frames. Preliminary photometry of OT in the both epochs\nas is follows.\n\nFilter, exp, t_start                t_end (UTC)         OT, mag\n        s,  (UT)                    (UT)\nB    620    2024-08-03T23:44:36 -- 2024-08-04T00:37:41 23.88 +/- 0.13\nV    600    2024-08-03T23:50:17 -- 2024-08-04T00:33:45 23.13 +/- 0.09\nRc   510    2024-08-03T23:47:46 -- 2024-08-04T00:35:28 22.82 +/- 0.07\nIc   510    2024-08-03T23:52:56 -- 2024-08-04T00:30:14 22.05 +/- 0.10\n\nV    900    2024-08-04T20:28:02 -- 2024-08-04T21:01:52 23.55 +/- 0.08\nRc   930    2024-08-04T20:23:36 -- 2024-08-04T21:03:41 22.91 +/- 0.06\n\nThe magnitudes were calibrated against nearby Pan-STARRS stars\nand not corrected for Galactic extinction.\n\nWe note significant reddening (V-Rc) between the two epochs.\n"
}