Electronic Telegram No. 2132 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 NOVAE IN M81 Kamil Hornoch, Astronomical Institute, Ondrejov; Jose Prieto, Carnegie Observatories; and Rubab Khan and Ondrej Pejcha, Department of Astronomy, Ohio State University, report their discovery of a nova in M81 on a co-added 600-s Sloan r' CCD frame taken by Prieto and Khan with RETROCAM on the 2.4-m Hiltner telescope at MDM observatory on Jan. 10.364 UT. The new object is visible on single 60-s images used for the co-added image, and on the co-added 1200-s image taken by Prieto and Khan with the same instrumentation on Jan. 11.368. Available Sloan r' magnitudes for the object, designated M81N 2010-01a, as measured by Hornoch: Jan. 8.333, [23.4; 10.364, 21.2 +/- 0.15; 11.368, 20.2 +/- 0.1; 14.394, 20.2 +/- 0.1; 15.471, 20.6 +/- 0.1. M81N 2010-01a is located at R.A. = 9h55m26s.22, Decl. = +69o06'18".9 (equinox 2000.0), which is 37".2 west and 143".8 north of the center of M81. Nothing is present at this position on numerous archive images from the 2.54-m Isaac Newton Telescope, the 4.2-m William Herschel Telescope, the 4-m Mayall telescope, and the 8.2-m Subaru telescope, down to limiting magnitudes as faint as Sloan r' = 23.3, R = 23.4, and V = 23.8. Low-resolution optical spectroscopy (range 400-750 nm, resolution 1.4 nm) was obtained using the Boller & Chivens CCD Spectrograph on the 2.4-m Hiltner telescope at MDM Observatory; a low-S/N spectrogram of M81N 2010-01a, taken by Prieto and Khan under poor seeing conditions on Jan. 15.37, exhibits a blue continuum with strong H-alpha in emission and very faint H-beta. The FWHM of H-alpha is about 1700 km/s. This confirms, that the object is classical nova in M81. Hornoch also measured additional Sloan r' magnitudes for recent novae in the same galaxy (cf. CBETs 2051, 2063): M81N 2009-11a, 2010 Jan. 11.368 UT, [22.7. M81N 2009-11b, Jan. 8.333, 23.0 +/- 0.3; 11.368, 23.4 +/- 0.2. M81N 2009-11c, Jan. 8.333, [23.0; 11.368, [23.1. NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2010 CBAT 2010 January 19 (CBET 2132) Daniel W. E. Green