TITLE: GCN CIRCULAR NUMBER: 14538 SUBJECT: GRB 130427A: Pan-STARRS 1 optical observations DATE: 13/05/03 04:00:34 GMT FROM: Heather Flewelling at IfA/Hawaii H. Flewelling, A. Schultz, N. Primak, K. C. Chambers, E. A. Magnier, W. Sweeney, C. Z. Waters, S. Chastel, M. E. Huber, I. Smith, report on behalf of Pan-STARRS 1: Pan-STARRS 1, a 1.8 m survey telescope located at Haleakala, Hawaii, observed GRB 130427A (Masell et al., GCNC 14448) a total of 4 times in the z and y filters using the 1.4 Gigapixel camera, in the course of normal survey operations. PS1 detected the afterglow (Elenin et al., GCNC 14450), and the observations were calibrated with the "ubercal" technique (Schafly et al 2011) and the PS1 reference catalog (Magnier et al 2012). The results are: t_mid(hr) exp(s) filter mag 108.18 80.0 y 19.52 +/- 0.10 108.21 80.0 y 19.66 +/- 0.09 111.35 60.0 z 19.84 +/- 0.07 111.37 60.0 z 19.81 +/- 0.06 Note the host galaxy pre-outburst has been observed in the PS1 3pi survey and thus photometry of the host galaxy is available. This discovery was made possible by the PS1 system operated by the PS1 Science Consortium and its member institutions ( http://www.ps1sc.org/PS1_System_GCN.shtml ). We thank the telescope operators of the PS1 telescope for their support.