Electronic Telegram No. 5265 Central Bureau for Astronomical Telegrams Mailing address: Hoffman Lab 209; Harvard University; 20 Oxford St.; Cambridge, MA 02138; U.S.A. e-mail: cbatiau@eps.harvard.edu (alternate cbat@iau.org) URL http://www.cbat.eps.harvard.edu/index.html Prepared using the Tamkin Foundation Computer Network PSN J14033858+5418421 = SUPERNOVA 2023ixf IN M101 Koichi Itagaki, Yamagata, Japan, reports his discovery of an apparent supernova (unfiltered mag 14.9) located 228" east and 134" south of the center of the galaxy M101 on frames taken on May 19.727 UT; his precise position for the variable of R.A. = 14h03m38s.58, Decl. = +54d18'42".1 (equinox J2000.0) yielded the provisional designation PSN J14033858+5418421 when Itagaki posted it to the Central Bureau's TOCP webpage. On May 20.486, Itagaki measured mag 13.0 and posted an image at URL http://k-itagaki.jp/images/2023ixf-20.jpg. PSN J14033858+5418421 has been designated SN 2023ixf by the IAU, and it has been found to be a type-II supernova. Additional reports to the Central Bureau are given below. S. Limeburner writes that exposures taken with a 20-cm Meade LX-200 reflector on May 19.159 UT show PSN J14033858+5418421 at mag 15.0, with it being offset 229" east and 141" south of the nucleus of M101; nothing is visible on a 5-min exposure taken by Limeburner on May 18.149 with the same telescope. S. Korotkiy, N. Potapov, and K. Sokolovsky reported unfiltered tri-color mag 14.3 on an image taken on May 19.753 with a Canon EOS 600Da CMOS camera (+ wide-field 80-mm refractor); they add that nothing was visible to limiting magnitude 17.0 some nineteen hours earlier, on May 18.9500. S. LaRiccia, Somerville, MA, USA, reports imaging SN 2023ixf with a Celestron Nexstar 6se telescope (+ QHY5III485C camera) on May 19.728 at unfiltered mag 14.9. E. Broens, Mol, Belgium, reports the following CCD Johnson/Cousins photometry of PSN J14033858+5418421 taken with a 0.28-m Schmidt-Cassegrain reflector: May 21.006, B = 11.92 +/- 0.01, V = 12.13 +/- 0.01, R_c = 12.11 +/- 0.01, I_c = 12.16 +/- 0.01; May 22.898, B = 10.98 +/- 0.01, V = 11.15 +/- 0.01, R_c = 11.15 +/- 0.01, I_c = 11.16 +/- 0.01. NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2023 CBAT 2023 May 24 (CBET 5265) Daniel W. E. Green