TITLE: GCN CIRCULAR NUMBER: 9452 SUBJECT: GRB 090530: NOT optical observations DATE: 09/05/30 23:26:56 GMT FROM: Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst D. Malesani, D. Xu, G. Leloudas, J.P.U. Fynbo (DARK/NBI), P. Jakobsson (Univ. Iceland), M.E. Brown (Caltech), E.L. Schaller (Univ. Hawaii), and T. Liimets (NOT & Tartu Obs.) report on behalf of a larger collaboration: We observed the field of GRB 090530 (Cannizzo et al., GCN 9438) with the NOT equipped with the MOSCA camera. Observations were carried out in the R band, starting on 2009 May 30.879 UT (17.8 hr after the GRB). The optical afterglow (Cannizzo et al., GCN 9438; Flewelling et al., GCN 9439; Morgan et al., GCN 9440) is clearly detected in a single 300s exposure, with a magnitude R = 21.6 assuming R = 18.17 for the USNO star at RA = 11:57:41.68, Dec = +26:35:43.3.