Electronic Telegram No. 5499 Central Bureau for Astronomical Telegrams Mailing address: Hoffman Lab 209; Harvard University; 20 Oxford St.; Cambridge, MA 02138; U.S.A. e-mail: cbatiau@eps.harvard.edu (alternate cbat@iau.org) URL http://www.cbat.eps.harvard.edu/index.html Prepared using the Tamkin Foundation Computer Network V7992 SAGITTARII = NOVA SAGITTARII 2025 No. 2 = TCP J17590439-3601111 Koichi Itagaki, Yamagata, Japan, reports his discovery of an apparent nova (mag 10.5) on unfiltered CCD frames taken on Jan. 29.882 UT with a 180-mm-f.l. f/2.8 camera lens. The variable star's position was given as R.A. = 17h59m04s.39, Decl. = -36d01'11".1 (equinox J2000.0), and it was automatically assigned the preliminary designation TCP J17590439-3601111 when Itagaki posted it to the Central Bureau's TOCP webpage. Itagaki has posted his image at website URL http://k-itagaki.jp/images/sgr-25-01-29.jpg. Andrew Pearce, Nedlands, Western Australia, reports his independent discovery of TCP J17590439-3601111 at mag 10.6 on three unfiltered images obtained on Jan. 29.846 UT (shortly before Itagaki's images were taken, but reported about an hour and a half later to the TOCP) with a Canon 800D camera (+ 85-mm-f.l. f/1.2 lens), providing position end figures 04s.45, 07".9. Pearce adds that closer inspection of recent patrol images confirm that the variable star was present on earlier images, albeit fainter, with the following magnitude estimates: 2024 Oct. 31.493, [12.5; 2025 Jan. 26.842, 11.1; 27.847, 11.0; 28.842, 11.1. Pearce provides the following additional V magnitudes for TCP J17590439-3601111, presumably obtained with a 0.05-m f/5 refractor: Jan. 30.849, 10.4; 31.849, 10.3; Feb. 1.844, 10.3; 2.844, 10.2. He also provides the following "TB" magnitudes (cf. CBET 5498): Jan. 30.849, 10.7; 31.849, 10.5; Feb. 1.844, 11.0; 2.844, 10.9. Pearce also reports that an unfiltered CCD image obtained by T. Lovejoy with a 0.25-m f/4 reflector at Rio Hurtado Valley, Chile, on Jan. 30.370 shows TCP J17590439-3601111 at mag 10.1 with position end figures 04s.25, 07".1 (Gaia DR3 catalogue stars used for reference), adding that this is within 0".4 of the Gaia star 4037465658505672832 (G magnitude 17.4). Spectroscopy obtained by E. Aydi et al. on Jan. 31 (no time provided) of TCP J17590439-3601111 with the 4.1-m Southern Astrophysical Research (SOAR) Telescope at Cerro Pachon in Chile show P-Cyg profiles for H I, Fe II, and O I, with the Balmer lines having a blue-shifted absorption around -1500 km/s, adding that this appears to be a classical nova near peak optical brightness (cf. website URL https://www.astronomerstelegram.org/?read=17012). E. Kazarovets writes that the permanent GCVS designation V7992 Sgr has been assigned to this nova. NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2025 CBAT 2025 February 3 (CBET 5499) Daniel W. E. Green