TITLE: GCN CIRCULAR NUMBER: 21567 SUBJECT: LIGO/Virgo G298048: Correction to Swope photometry announced in LVC GCN 21529 DATE: 17/08/18 17:19:22 GMT FROM: Ryan Foley at UCSC D. A. Coulter, C. D. Kilpatrick, M. R. Siebert, R. J. Foley (UCSC), B. J. Shappee, M. R. Drout, J. S. Simon, and A. L. Piro (Carnegie) on behalf of the One-Meter Two-Hemisphere (1M2H) collaboration: We report a correction to the photometric magnitude of SSS17a announced in LVC GCN 21529. After re-examination of the imaging and using 97 APASS i' standards for relative photometry, we conclude that the source had a brightness of i = 17.3 +/- 0.1 mag at the time of observation on UT 2017-08-17.98. We apologize for the error.