Electronic Telegram No. 5612
Central Bureau for Astronomical Telegrams
Mailing address:  Hoffman Lab 209; Harvard University;
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Prepared using the Tamkin Foundation Computer Network


V7994 SAGITTARII = NOVA SAGITTARII 2025 No. 4 = TCP J18035290-3127298
     John Seach, Grafton, NSW, Australia, reports his discovery of another
apparent nova (mag 10.2) on three unfiltered exposures obtained on Sept.
21.381 UT with a DSLR camera (+ 40-mm-f.l. f/1.4 lens).  Seach gave the
object's position as R.A. = 18h03m52s.90, Decl. = -31d27'29".8 (equinox
J2000.0), and the designation TCP J18035290-3127298 was automatically
assigned to this variable when he posted it to the Central Bureau's TOCP
webpage.  Seach adds that there is no variable star listed as being brighter
than mag 12.7 within 1'.3 of this position, and nothing is visible on three
images obtained by Seach with the same instrumentation on Sept. 20.380
(limiting mag 11.0).  He further notes that nothiing is visible at this
position on a red plate from the Palomar Digital Sky survey, but cautions
that this is a crowded star field.  Additional imaging by Seach on Sept.
22.376 indicates that the variable had brightened to (unfiltered) mag 8.5.
     Within half an hour of Seach's posting his discovery to the TOCP, Tadashi
Kojima (Tsumagoi, Gunma-ken, Japan) posted his own independent discovery of
this variable (unfiltered mag 10.5) from three 4-s exposures (limiting mag
13.7) taken on Sept. 21.420 UT with a Canon EOS 6D digital camera (+ 300-mm-
f.l. f/2.8 lens), with position end figures 52s.78, 24".0.  When he posted it
to the TOCP, it received a second designation:  TCP J18035278-3127240.  He
adds that nothing is visible at this position on imaging by Kojima with the
same instrumentation on Sept. 17.419 (limiting mag 13.5).
     H. Yamaoka, National Astronomical Observatory of Japan, forwarded
a third independent discovery of TCP J18035290-3127298 at mag about 10.6 by
Kazuyoshi Kanatsu (Shimane, Japan) on three images obtained on Sept. 21.484 UT
using a Pentax K30 digital camera (+ 135-mm-f.l. lens at ISO 1600), providing
position end figures 52s.75, 24".7.  Yamaoka adds that images from the
"All-Sky Automated Survey for SuperNovae" (ASAS-SN) show the variable at
mag about 11.2 on Sept. 21.096.
     A. Pearce, Nedlands, Western Australia, measured position end figures
52s.75, 26".5 (and magnitudes TB = 9.02, V = 8.78, TR = 8.43) for
TCP J18035290-3127298 from CMOS camera imaging on Sept. 22.480 UT with a
0.05-m refractor at Perth (Gaia DR2 star positions), noting that the variable
is within 0".7 of Gaia DR3 catalogue star 4043865232860503296 (G mag 19.8).
     K. Yoshimoto, Yamaguchi, Japan, reports position end figures 52s.76,
26".7 (and magnitudes V = 8.58, I = 7.74) for TCP J18035290-3127298 from CMOS
imaging on Sept. 22.521 UT with an iTelescope 0.43-m f/6.8 reflector located
at Siding Spring, NSW, Australia.  He has posted an image at website URL
http://orange.zero.jp/k-yoshimoto/TCP_J18035290-3127298_20250922.jpg.
     O. Chernyshenko, "New Milky Way (NMW) Survey"; S. Korotkiy, Astroverty
and Ka-Dar, Karachay-Cherkessia, Russia; and S. Sokolovsky, Department of
Astronomy, University of Illinois, report that TCP J18035290-3127298 appears
at mag 8.5 on unfiltered CCD images obtained on Sept. 22.694 UT with the
NMW wide-field survey camera (+ 135-mm-f.l. f/2 telephoto lens).
     A. Amorim (Florianopolis, Brazil) reports visual mag 8.2 for TCP
J18035290-3127298 on Sept. 22.949 UT (0.9-m f/10 refractor; Tycho-2
catalogue star magnitudes via AAVSO Chart X40777KR).
     Kojimi has forwarded a report by M. Fujii (Okayama, Japan), who obtained
spectroscopy of TCP J18035290-3127298 on Sept. 22.451 UT at the Fujii Kurosaki
Observatory using a 0.4-m telescope (+ NLS-II spectrograph; resolution about
1000).  Emission lines of H-alpha, H-beta, He I (587.6 nm) and O I (777.3 nm)
with P-Cyg profiles are present, with the H-alpha absorption component showing
a blueshift of 800 km/s, adding that these features are characteristic of a
nova.  The spectrum has been posted at the following website URL:
https://otobs.org/FBO/fko/n/tcp_j18035278-3127240/tcp_j18035278-3127240.htm.
     E. Kazarovets (Institute of Astronomy, Moscow) informs the Bureau that
the permanent GCVS designation V7994 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 September 23                (CBET 5612)              Daniel W. E. Green