TITLE: GCN CIRCULAR NUMBER: 24687 SUBJECT: GRB 190530A: OAJ optical detection DATE: 19/05/30 23:12:12 GMT FROM: Luca Izzo at IAA-CSIC L. Izzo (HETH/IAA-CSIC), A. de Ugarte Postigo (HETH/IAA-CSIC, DARK/NBI), D. A. Kann, M. Blazek, C. C. Thoene, K. Bensch (all HETH/IAA-CSIC), J.L. Lamadrid, F. López-Martínez, M. C. Díaz-Martín andH. Vazquez Ramio (all CEFCA) report: We observed the field of GRB 190530A (Fermi-GBM team, GCN 24676; Biltzinger et al., GCN 24677; Longo et al., GCN 24679; Lucarelli et al., GCN 24678; Verecchia et al., GCN 24683) with the 0.8m telescope of the Observatorio Astrofisico de Javalambre (Teruel, Spain). Observations consisted of a series of 300 s g'r'i' exposures, starting at 20:53:37 UT (0.44 days after the GRB trigger). We do not detect any source within the LAT error circle (Longo et al., GCN 24679) itself down to the DSS2 limit. The afterglow reported by Lipunov et al. (GCN 24680) is clearly detected at the following position (J2000.0, +/-0.5"): RA = 08:02:07.84 Dec. = +35:28:47.1 consistent with the position reported by Lipunov et al. We note this position lies outside the Fermi LAT error circle. We measure the following magnitudes, as compared to a nearby SDSS star: filter | mag (AB) | time (days) ———————————————————————————————- g | 17.91 +- 0.07 | 0.444 r | 17.56 +- 0.08 | 0.448 i | 17.38 +- 0.08 | 0.440