Electronic Telegram No. 824 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://cfa-www.harvard.edu/iau/cbat.html (2478) TOKAI D. Higgins, Canberra, Australia; P. Pravec and P. Kusnirak, Ondrejov Observatory; B. Warner, Palmer Divide Observatory, Colorado Springs, CO; A. Galad, Modra Observatory; J. Oey, Leura, N.S.W., Australia; R. Goncalves, Linhaceira, Tomar, Portugal; and W. Cooney, J. Gross, and D. Terrell, Sonoita Research Observatory, Sonoita, AZ, report that photometric observations obtained during Jan. 20-28 reveal that minor planet (2478) is a synchronous binary system with a period of 25.885 +/- 0.007 hours. A combined rotation lightcurve has an amplitude of 0.41 mag, and superimposed mutual events indicate a lower limit on a secondary-to-primary mean-diameter ratio of 0.72. NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2007 CBAT 2007 January 30 (CBET 824) Daniel W. E. Green