TITLE: GCN CIRCULAR NUMBER: 10657 SUBJECT: Swift Trigger 420256: IAC80 R-band observations DATE: 10/04/23 07:22:05 GMT FROM: Javier Gorosabel at IAA-CSIC J. Gorosabel (IAA-CSIC), C. Zurita (IAC), A. de Ugarte Postigo (INAF- OAB), on behalf of a larger collaboration report: "We have observed the field of Swift trigger 420256 (Hoversten et al., GCNC 10654) with the 80-cm IAC80 telescope on the observatory of Teide, Tenerife, Spain. The observations were conducted in the R-band on April 23.1453-23.1906 UT (0.75-1.84 hours post burst) with a total exposure time of 3000s. Visual comparison to the DSS reveals no new sources in the co-added image within the Swift/BAT error circle brighter than R=19 (USNO-B1.0 calibration)."