TITLE: GCN CIRCULAR NUMBER: 19964 SUBJECT: GRB 160927A: Magellan imaging DATE: 16/09/28 18:36:06 GMT FROM: Wen-fai Fong at U of Arizona W. Fong (Univ. of Arizona), S. Sheppard (Carnegie DTM) and E. Berger (Harvard) report: We imaged the location of the short-duration GRB 160927A (Gibson et al., GCN 19952) with the Inamori-Magellan Areal Camera and Spectrograph (IMACS) mounted on the Magellan/Baade 6.5-m telescope at a mid-time of 2016 Sep 28.00 UT (5.94 hr post-burst). We obtained 4x200-sec of r-band exposures in 0.75" seeing at an airmass of 1.9. We clearly detect the optical afterglow (Tkachenko et al., GCN 19954; D'Avanzo et al., GCN 19956; Wiseman et al., GCN 19959; Xu et al., GCN 19960). Tied to 10 SDSS stars in the field, we calculate a magnitude of r_AB=23.84 +/- 0.21, not corrected for Galactic extinction in the direction of the burst.