Electronic Telegram No. 1053 Central Bureau for Astronomical Telegrams INTERNATIONAL ASTRONOMICAL UNION M.S. 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A. IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions) CBAT@CFA.HARVARD.EDU (science) URL http://www.cfa.harvard.edu/iau/cbat.html HS 2331+3905 M. Templeton and E. O. Waagen, AAVSO, have informed us of apparently the first known outburst of the cataclysmic variable HS 2331+3905 (R.A. = 23h34m01s.55, Decl. = +39o21'42".9, equinox 2000.0; position from AAVSO Alert Notice 357, apparently originally from the USNO B1.0 catalogue). The variable was discovered in the course of the Hamburg Quasar Survey [see Araujo-Betancor et al. 2004, Proc. IAU Colloq. 194, in Revista Mex. Astron. Astrofis. (Serie de Conferencia) 20, 190; Araujo-Betancor et al. 2005, A.Ap. 430, 629]. Templeton notes that the variable is near V mag 16.4 at quiescence. Selected AAVSO CCD magnitudes (unfiltered unless otherwise noted): Sept. 3.192 UT, 16.2 (G. Poyner, Birmingham, England); 3.194, V = 16.3 (F. Gobet, Cestas, France); 4.924, V = 12.26 (D. Rodriguez, Madrid, Spain); 4.924, V = 12.21 (Rodriguez); 4.924, V = 12.21 (Rodriguez); 4.927, V = 12.19 (Rodriguez); 4.928, V = 12.16 (Rodriguez); 4.929, V = 12.19 (Rodriguez); 4.930, V = 12.14 (Rodriguez); 4.973, V = 11.53 (C. Gualdoni, Como, Italy); 5.096, V = 10.87 (R. Koff, Bennett, CO, U.S.A.); 5.150, V = 10.53 (G. Waddill, Richmond, VA, U.S.A.); 5.164, V = 10.41 (M. Nicholson, Daventry, England); 5.165, B = 10.49 (Nicholson); 5.243, V = 10.06 (Nicholson); 5.269, V = 10.02 (R. Huziak, Saskatoon, SK, Canada); 5.350, V = 9.70 (Huziak); 5.352, V = 9.60 (Nicholson); 5.400, V = 9.34 (Nicholson); 5.417, B = 9.30 (Nicholson); 5.430, V = 9.10 (Nicholson); 5.460, V = 9.05 (Nicholson); 5.472, V = 9.15 (Nicholson); 5.473, B = 9.10 (Nicholson); 5.483, V = 8.97 (Huziak). Visual magnitude estimates, in part from Waagen: Sept. 3.87, [14.2 (P. Schmeer, Bischmisheim, Germany); 3.893, [14.6 (E. Muyllaert, Oostende, Belgium); 4.843, 13.9 (Muyllaert); 4.868, 12.8 (Schmeer); 4.894, 12.6 (Schmeer); 4.961, 12.0 (Schmeer); 5.082, 10.8 (M. Komorous, London, Ontario, Canada); 5.099, 10.4 (J. Bortle, Stormville, NY, U.S.A.); 5.121, 10.6 (Schmeer); 5.148, 10.5 (Schmeer); 5.194, 10.2 (Komorous); 5.274, 9.6 (Komorous); 5.310, 9.6 (Komorous); 5.333, 9.8 (Komorous); 5.360, 9.5 (Komorous). NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2007 CBAT 2007 September 5 (CBET 1053) Daniel W. E. Green