Electronic Telegram No. 3628 Central Bureau for Astronomical Telegrams INTERNATIONAL ASTRONOMICAL UNION CBAT Director: Daniel W. E. Green; 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 NOVA DELPHINI 2013 = PNV J20233073+2046041 S. Nakano, Sumoto, Japan, reports the discovery by Koichi Itagaki (Teppo-cho, Yamagata, Japan) of an apparent nova (mag 6.8) on an unfiltered CCD frame taken on Aug. 14.584 UT using a 0.18-m reflector, with confirming unfiltered images taken with a 0.60-m f/5.7 reflector on Aug. 14.750 that show the variable at mag 6.3. The new object is located at R.A. = 20h23m30s.73, Decl. = +20d46'04".1 (equinox 2000.0). Itagaki posted his discovery image at website URL http://www.k-itagaki.jp/images/pnv-del.jpg. The variable was designated PNV J20233073+2046041 when it was posted at the Central Bureau's TOCP webpage. Additional CCD magnitudes (unfiltered unless noted otherwise) for PNV J20233073+2046041: May 13.998, 17.1 (D. Denisenko, V. Lipunov, E. Gorbovskoy, A. Parkhomenko, A. Tlatov, D. Dormidontov, and V. Senik; double 0.40-m f/2.5 robotic MASTER-Kislovodsk reflector; limiting mag 18.9); Aug. 13.565, [13.0 (Itagaki); 14.8, 6.8 (Ernesto Guido, Nello Ruocco, and Nick Howes; remotely using a 0.43-m f/6.8 astrograph near Nerpio, Spain; position end figures 30s.72, 03".4; UCAC-3 catalogue reference stars); 14.8, R = 6.1 (Guido et al.; 0.25-m f/6.3 telescope at Sorrento, Italy; unfiltered mag 6.9; position end figures 30s.68, 03".7; CMC-14 catalogue reference stars; confirmation image posted at website URL http://bit.ly/15FLJaK, with an animation comparing their image and a 1990 red Digitized Sky Survey plate is posted at URL http://bit.ly/13AVFTy); 14.802, R = 6.4 (Sergey Shurpakov, Baran, Belarus; 0.20-m f/4 reflector + Artemis 285AL camera; position end figures 30s.95, 05".6; CMC-14 reference stars; image posted at website URL http://www.taurusskystars.narod.ru/confirm.html); 14.817, V = 6.2 (Wolfgang Vollmann, Vienna, Austria; digital SLR camera with 50-mm-f.l. f/2.8 lens); 14.826, 7.7 (Denisenko et al.; MASTER-Kislovodsk reflector; limiting mag 18.7; image posted at URL http://master.sai.msu.ru/static/OT/NovaDel2013-MASTER.jpg); 14.894, 6.8 (Gianluca Masi, Patrick Schmeer, and Francesca Nocentini; remotely using the 43-cm robotic telescope at Ceccano, Italy; position end figures 30s.68, 03".7); 14.897, 6.5 (Uwe Reichert, Schwetzingen, Germany; Canon 6D camera + 180-mm-f.l. f/5.6 lens at ISO 6400); 14.923, B = 6.77, V = 6.10, R = 5.62 (L. Izzo and L. D'Avino; remotely with a 0.15-m f/7.3 telescope near Nerpio, Spain; iTelescope T16); 14.952, B = 6.72, V = 6.66, R = 6.32, B-V = +0.06 (T. Yusa, Osaki, Japan; remotely using a 0.43-m f/6.8 astrograph at the RAS observatory near Nerpio, Spain); 14.96, 6.6 (P. Bacci, San Marcello Pistoiese, Italy; 0.60-m f/4 telescope; animated image posted at website URL http://tiny.cc/t5xt1w); 15.14, 6.0 (Quanzhi Ye, London, ON, Canada; Canon G11 camera). Visual magnitude estimates for PNV J20233073+2046041: Aug. 14.821 UT, 6.2 (M. Reszelski, Szamotuly-Galowo, Poland, 15x70 binoculars); 14.829, 6.0 (Patrick Schmeer, Bischmisheim, Germany); 14.884, 6.4 (K. Hornoch, Pancir, Czech Republic, 10x50 binoculars); 14.915, 6.3 (E. Broens, Mol, Belgium); 15.015, 6.3 (R. Fidrich, Budapest, Hungary, 20x60 binoculars); 15.035, 6.0 (Gustav Holmberg, Lund, Sweden). Schmeer adds that there is a star of blue magnitude 17 (and V = 16.86, from The Guide Star Catalogue, Version 2.3.2) that is located about 0".3 from the position of the possible nova at position end figures 30s.714, 04".22. Denisenko et al. suggest that the variable is identical to the blue star USNO-B1.0 1107-0509795 (position end figures 30s.713, 03".97; blue mag 17.2- 17.4, red mag 17.4-17.7) and to the ultraviolet source GALEX J202330.7+204603 (NUV magnitude 17.9); their color-combined (BRIR) Digitized Sky Survey finder chart posted at http://master.sai.msu.ru/static/OT/J202330+204604-BRIR5x5.jpg (field-of-view 5' x 5') has the proposed precursor marked. Strong H-alpha emission has been noted by Masi et al. (low-resolution spectra taken with a 36-cm robotic telescope at Ceccano; scale about 3.4 nm/pixel; Aug. 14.92 UT) and by Olivier Garde (Observatoire de la Tourbiere, France; C14 telescope; resolution 10000; echelle spectrograph). Further spectroscopy by Masi et al. on Aug. 15.03 (noting the use of a 100 lines/mm diffraction grating under better skies) confirms the emission at H-alpha but with emission at H-beta also noted. NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2013 CBAT 2013 August 15 (CBET 3628) Daniel W. E. Green