Circular No. 8935 Central Bureau for Astronomical Telegrams INTERNATIONAL ASTRONOMICAL UNION Mailstop 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 ISSN 0081-0304 Phone 617-495-7440/7244/7444 (for emergency use only) V2491 CYGNI D. K. Lynch, R. W. Russell, and R. J. Rudy, The Aerospace Corporation; C. E. Woodward, University of Minnesota; and G. J. Schwarz, West Chester University, report on SpeX observations (wavelength range 0.8-2.5 microns) of V2491 Cyg (cf. IAUC 8934) obtained at the Infrared Telescope Facility on Apr. 12.56 UT: "The object is definitely a nova, but its spectrum is highly unusual. It has extremely broad lines (FWHM of 5500 km/s) with complex profiles. Fe II may be present in the infrared spectrum, but it is difficult to confirm this object as an 'Fe II' nova due to masking of the infrared Fe II emission lines by stronger features. The neutral helium line at 1.083 microns has already appeared, which is early for an 'Fe II' nova. This, together with the breadth of the lines, plus strong emission features of N I and N II, suggests that this may be a rarer helium-nitrogen nova. The O I lines indicate a reddening of only E(B-V) = 0.3, a result supported by the blue nature of the overall spectrum. The probable identification of V2491 Cyg with a known x-ray source (Ibarra and Kuulkers, http://www.astronomerstelegram.org/?read=1473) makes this a potentially important source. Observations at all wavelengths are encouraged." Visual magnitude estimates, supplied in part by E. Waagen, AAVSO: Apr. 12.153 UT, 8.4 (P. Schmeer, Bischmisheim, Germany); 12.979, 8.3 (W. Vollmann, Vienna, Austria); 13.372, 9.0 (R. Tyson, Freeport, NY, U.S.A.); 14.436, 9.0 (T. Bretl, Plymouth, MN, U.S.A.). NR TRIANGULI AUSTRALIS This nova (cf. IAUC 8931) has brightened, as indicated by the following CCD V magnitudes from G. Bianciardi, University of Siena (remotely using a 0.30-m reflector near Sydney, N.S.W.): Apr. 7.678 UT, 9.22; 8.500, 9.39; 9.699, 9.09; 10.648, 9.20; 11.670, 8.84; 13.712, 8.39. COMET C/2006 B7 (ODAS) Further to IAUC 8929, E. J. Christensen had sent a potential single-night recovery of this comet from Mt. Lemmon 1.5-m telescope images on 2005 Oct. 7, noting the comet then to be extremely diffuse with a roughly round 10" coma and of magnitude 20.1 in targeted 120-s survey images. These observations were used in the improved orbital elements by G. V. Williams on MPEC 2008-G10, which utilize the A_3 nongravitational-force parameter normal to the orbit plane, following a demonstration of the value of A_3 in this particular case by S. Nakano, Sumoto, Japan. (C) Copyright 2008 CBAT 2008 April 14 (8935) Daniel W. E. Green Central Bureau for Astronomical Telegrams INTERNATIONAL ASTRONOMICAL UNION Mailstop 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 ISSN 0081-0304 Phone 617-495-7440/7244/7444 (for emergency use only) V2491 CYGNI S. Nakano, Sumoto, Japan, reports the discovery by Koichi Nishiyama (Kurume, Fukuoka-ken, Japan) and Fujio Kabashima (Miyaki- cho, Saga-ken, Japan) of a possible nova (mag 7.7) on two 20-s unfiltered CCD frames (limiting mag about 12.5) taken on Apr. 10.728 UT using a 105-mm-f.l. f/5.6 camera lens; their unfiltered CCD images taken on Apr. 10.787 and 11.668 with a 0.40-m reflector yields R.A. = 19h43m01s.96, Decl. = +32o19'13".8 (equinox 2000.0), and mag 7.7 and 7.1 for the variable; nothing is visible at this position on their past survey frames taken on Apr. 3.717 (limiting mag 12.5) and 7.727 (limiting mag 12.7). Following posting on the Central Bureau's unconfirmed-objects webpage, J. Beize (Beijing, China) reports the apparent independent discovery of this possible nova at mag approximately 8.0 by Z.-w. Jin and X. Gao on several 60-s survey images (limiting mag about 15.0) taken by Gao on Apr. 10.831 with a Canon EOS-350D camera (+ 7-cm-aperture, 200-mm-f.l. f/2.8 lens) at Xingming Observatory, Mt. Nanshan, with Beize measuring position end figures 02s.00, 10".1 for the variable; nothing was visible at this position on Xingming images taken on Apr. 8.831 (limiting mag about 14). H. Yamaoka, Kyushu University, writes that K. Haseda (Toyohashi, Aichi, Japan) finds nothing brighter than mag 12.3 at the reported position for the variable on his patrol images taken on Apr. 4.774 with a Canon EOS-5D digital camera + 120-mm-f.l. lens. E. Guido and G. Sostero, Remanzacco, Italy, report that their confirming CCD images taken remotely with a 0.25-m reflector near Mayhill, NM, U.S.A., on Apr. 11 show the apparent nova at position end figures 01s.98, 13".5 (UCAC-2 catalogue reference stars). Sostero and Guido add that comparison with a Palomar Oschin Schmidt telescope plate obtained on 1995 Aug. 3, shows the presence at this position of an apparent star with red mag about 18; they also provide the following magnitudes (uncertainty +/- 0.05 mag in each color): Apr. 11.36, B = 8.06, V = 7.54, R = 7.04; 11.46, 8.20, 7.77, 7.15. G. Klingenberg, Mo i Rana, Norway, reports the following magnitudes for the variable from CCD images taken with a 25-cm reflector near Mayhill: Apr. 11.333, V = 7.63; 11.335, B = 8.06; 11.440, V = 7.74; 11.443, B = 8.15. Nakano adds that an unfiltered CCD taken by K. Kadota (Ageo, Saitama-ken, Japan, 0.25-m reflector) on Apr. 11.741 yields mag 7.4 and position end figures 01s.98, 14".1; Kadota notes that a USNO- B1.0-catalogue star has position end figures 02s.039, 13".84 and red magnitudes 15.5 and 16.3 (different epochs evidently from Palomar Sky Survey plates). N. N. Samus, Institute of Astronomy, Moscow, informs us that this object is being assigned the variable-star designation V2491 Cyg. (C) Copyright 2008 CBAT 2008 April 11 (8934) Daniel W. E. Green Central Bureau for Astronomical Telegrams INTERNATIONAL ASTRONOMICAL UNION Mailstop 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 ISSN 0081-0304 Phone 617-495-7440/7244/7444 (for emergency use only) NR TRIANGULI AUSTRALIS = NOVA TRIANGULI AUSTRALIS 2008 Nicholas J. Brown, Quinns Rocks, Western Australia, reports his discovery of a possible nova (mag 9.2) on two T-Max 400 films taken on Apr. 1.73 UT with a 135-mm f/2 camera lens, giving the variable's position approximately as R.A. = 16h18m47s, Decl. = -60o27'57" (equinox 2000.0; uncertainty estimated as about 10"); Brown adds that no star is visible at this position on his film from Mar. 16.76 (limiting mag 11.5), and nothing is visible to mag about 14 in this position on the Digitized Sky Survey. A catalogued star of mag 13.5-14.0 is visible to the northwest of the variable. Brown's visual observation of the variable on Apr. 2.74 yields mag approximately 9.0; he also estimated visual mag 10.1 on Apr. 4.695. Following posting on the Central Bureau's unconfirmed- objects webpage, A. Amorim, Florianopolis, Brazil, reports the following visual magnitude estimates for the variable: Apr. 3.158, 9.3; 4.097, 9.9. W. Liller, Vina del Mar, Chile, reports that a Technical Pan photo (limiting mag about 11.0) taken with an 85-mm camera lens on Mar. 31.33 through an orange filter shows a faint but definite image of the apparent nova at magnitude approximately 10.5; nothing brighter than mag about 11 appears on a photo taken by Liller on Mar. 15. E. Guido and G. Sostero write that their remote imaging with a 0.31-m f/9 reflector of the Remote Astronomical Society (RAS) located near Moorook, Australia, on Apr. 4.86 yields the following precise position for the presumed nova: R.A. = 16h18m48s.21, Decl. = -60o27'48".9 (equinox 2000.0; UCAC-2 catalogue reference stars). C. Jacques, Belo Horizonte, Brazil, also remotely obtained a 10-s unfiltered CCD image on Apr. 4.875 with an RAS 25-cm f/6 reflector at the Moorook Observatory, yielding mag 10.2 and position end figures 48s.20, 49".1. Jacques adds that comparison with a European Southern Observatory red image taken on 1984 Apr. 6 shows nothing at this position (estimated limiting magnitude 19.2), the nearest visible star having position end figures 47s.99, 45".8. N. N. Samus, Institute of Astronomy, Russian Academy of Sciences, informs us that this nova is being assigned the variable-star designation NR TrA. COMET C/2007 W1 (BOATTINI) Visual total-magnitude and coma-diameter estimates: Mar. 6.08 UT, 12.7, 2'.2 (J. J. Gonzalez, Leon, Spain, 0.20-m reflector); 29.07, 10.3, 8' (M. Goiato, Aracatuba, Brazil, 0.22-m refl.); 31.53, 10.2, 3'.2 (K. Yoshimoto, Yamaguchi, Japan, 0.25-m reflector); Apr. 2.09, 9.5, 6' (Gonzalez, 25x100 binoculars); 3.98, 8.9, 10' (Gonzalez, Asturias, Spain, 10x50 binoculars). (C) Copyright 2008 CBAT 2008 April 4 (8931) Daniel W. E. Green