TITLE: GCN CIRCULAR NUMBER: 15755 SUBJECT: Correction: MAXI J1421-613: Skynet PROMPT/R-COP observations DATE: 14/01/20 15:56:15 GMT FROM: Adam S. Trotter at UNC-Chapel Hill/PROMPT/Skynet A. Trotter, D. Reichart, A. Verveer, T. Spuck, A. LaCluyze, J. Haislip, A. Foster, N. Frank, K. Ivarsen, J. Moore, M. Nysewander, R. Beauchemin, T. Berger, M. Carroll, H. T. Cromartie, R. Egger, M. Hinckle, A. Ireland, M. Maples, L. Scott, and J. A. Crain report: In GCN 15753 (Trotter et al.), we mistakenly conflated the transient source MAXI J1421-613 (Baumgartner et al., GCN 15749, Swift trigger 584155) with GRB 140118 (Krim et al., GCN 15748, Lien et al., GCN 15750, Swift trigger 584136). We regret the error, and thank our colleagues who pointed it out. A corrected version of our observing report follows: Skynet observed the Swift-XRT localization of transient source MAXI J1421-613 (Baumgartner et al., GCN 15749, Swift trigger 584155) with one 24" and four 14" telescopes of the PROMPT array at Cerro Tololo, Chile, with two 14" telescopes of the PROMPT array at Siding Spring, Australia, and with the 14" R-COP telescope at Perth Observatory, Australia. Observations began 86s after the trigger, simultaneously in the BVRI bands. We detect no uncatalogued optical source in the Swift-XRT error circle. In stacks of exposures, we obtain the following upper limits: Mean Time Band Limit 10.8m I >19.6 14.9m R >19.1 11.7m V >19.8 14.9m B >19.1 6.94h I >17.3 7.10h R >16.9 6.02h V >20.4 6.04h B >20.4 Photometry is calibrated to five APASS-DR7 stars in the field, and has not been corrected for the extremely significant Galactic foreground extinction corresponding to E(B-V)=10.5 (Schlegel et al. 1998). No further Skynet observations are scheduled.