Electronic Telegram No. 463 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 COMET 174P/ECHECLUS S. Tegler, Northern Arizona University; G. Consolmagno, Vatican Observatory; and W. Romanishin, University of Oklahoma, obtained R-band CCD images on Apr. 2.3 UT with the Vatican Advanced Technology 1.8-m telescope at Mt. Graham, which show that the coma previously reported around this object (IAUCs 8656, 8660, 8677) has developed a complex structure. A low-surface-brightness coma of diameter 2' is centered 1' east of the nuclear condensation. A higher-surface-brightness condensation about 12" in diameter is centered about 7" west of the nuclear condensation, which itself is of mag R about 20.1 and is clearly offset from the center of the higher-surface-brightness structure, suggesting a detached coma produced by a transient event. A rough measurement of the entire 2'-diameter object gives a total R magnitude of = 16, while the higher-surface-brightness region has R = 17.9 (as measured in a 12"-diameter circle centered 7" west of the nuclear condensation). Images can be found at http://observatory.ou.edu. NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2006 CBAT 2006 April 5 (CBET 463) Daniel W. E. Green