Electronic Telegram No. 934 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 V5558 SAGITTARII T. Iijima, Astronomical Observatory of Padova, Asiago, reports that medium-dispersion spectra (range 360-760 nm, resolution 1000) of V5558 Sgr (cf. IAUC 8832) were taken on Apr. 20.12 and 20.14 UT at Asiago Astrophysical Observatory with a Boller-and-Chivens spectrograph mounted on the 1.22-m reflector. The spectra show prominent narrow emission lines of H I and He I (e.g., equivalent width -3.4 nm and FWHM = 480 km/s for H_beta, and -0.50 nm and 360 km/s for He I 587.6-nm). Weak emissions of some Fe II lines of multiplets 37, 42, and 49 were seen, and Mg II, Si II, and probably N II were also noticed in emission. Most of the prominent emission lines were accompanied by a weak absorption component blueshifted by 400-500 km/s with respect to the line center of the emission body. This object could be a rather peculiar classical nova in the pre-maximum stage. H. Naito and K. Matsuda, Nishi-Harima Astronomical Observatory; and H. Yamaoka, Kyushu University, report that a low-resolution spectrum (range 410-670 nm; resolution 1500 at H_alpha) of V5558 Sgr was obtained on Apr. 20.80 UT with the 2.0-m NAYUTA telescope (+ MALLS), showing a smooth continuum with emission lines of the Balmer series and P-Cyg profiles of He I 492.2-nm (+ Fe II 492.4-nm), 501.50nm (+ Fe II 492.4-nm), 504.8-nm, 587.6-nm, 667.8-nm, and Fe II 516.9-nm. The expansion velocity, derived from the FWHM of the Balmer series (H_alpha, H_beta, H_gamma), is 500, 520, and 540 km/s, respectively. Notable Na I D absorption lines suggest that our view of the nova suffers some reddening. The overall feature of the spectrum does not resemble that of a classical nova, but with the amplitude (> 10 mag) of outburst and the absence of a pre-outburst counterpart in the infrared or x-ray regions, it could be very remarkable object. Visual magnitude estimate of V5558 Sgr by A. Amorim, Florianopolis, Brazil: Apr. 21.196 UT, 10.0. NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2007 CBAT 2007 April 22 (CBET 934) Daniel W. E. Green