{
  "submittedHow": "email",
  "submitter": "Alberto Castro-Tirado at Inst.de Astro. de Andalucia <ajct@iaa.es>",
  "body": "S. Guziy, F. J. Aceituno, A. J. Castro-Tirado, M.D. Caballero-García, M. Gritsevich, I. Pérez-García, R. Sánchez-Ramírez, S.-Y. Wu (IAA-CSIC) and A. Fernández-Martin and M. M. Sánchez-Andújar (CAHA), on behalf of a larger collaboration,report:\n\nWe observed EP260416a (Hu et al., GCN 44307) with both the 1.5m telescope at Observatorio de Sierra Nevada (OSN) and the 2.2m telescope at Calar Alto Observatory (CAHA), in Southern Spain.  A series of 300 s BVRI exposures were obtained at the 1.5m OSN starting on Apr 17, 21:04 UT, complemented by one 100s i-band image at the 2.2m CAHA, on Apr 18, 01:04 UT., i.e. 39.6 h and 43.6 h respectively, after the initial trigger.\n\nThe optical counterpart (Ducoin et al., GCN 44310; Li et al., GCN 44315; Hua et al., GCN 44318; Lee et al., GCN 44319; Zheng et al., GCN 44321; Martin-Carrillo et al., GCN 44328; Li et al., GCN 44334, He et al. GCN 44336, An et al. GCN 44339, Jelinek et al. GCN 44341) is well detected in our images. We measure B = 21.08 +/- 0.14  and R = 20.99 +/- 0.07 on Apr 17, 21:15 UT and I = 19.82 +/-0.18 on Apr 18, 01:04 UT (none corrected for Galactic extinction).\n\nThe night after, a second epoch BVRI observation was conducted at the 1.5m OSN, for which measure R = 21.59 +/- 0.10 on Apr 18, 20:14 UT.  Our measurement is consistent with the continued fading of the afterglow.\n\nFurther optical monitoring is being carried out.\n\n",
  "subject": "EP260416a: 1.5m OSN and 2.2m CAHA optical monitoring",
  "eventId": "EP260416a",
  "createdOn": 1776657839219,
  "circularId": 44351
}