Following the posting on the CBET 4811 & 4812 about the NOVA RETICULI 2020 we performed some follow-up of this object through a TEL 0.1-m f/3.6 astrograph + CCD located in the Heaven's Mirror Observatory, Australia (MPC code Q56) and operated by Telescope Live network.
On images taken on July 16.82, 2020 we can confirm the presence of an optical counterpart (with R-filtered magnitude about +4.5; B-filtered magn. +5.6; V-filtered magn. +5.6) at coordinates:
R.A. = 03 58 29.61, Decl.= -54 46 39.8
(equinox 2000.0; Gaia DR2 catalogue reference stars for the astrometry).
This transient was discovered by Robert H. McNaught (Coonabarabran, NSW, Australia) as an apparent 5th-magnitude nova on CCD images obtained on July 15.590 UT with a Canon 6D camera and an 8-mm-f.l. f/2.8 lens (at ISO 800). The position is very close to an object listed as "MGAB-V207" in the AAVSO's VSX online database (which gives position R.A. = 3h58m29s.55, Decl. = -54d46'41".2, equinox J2000.0, which calls it a novalike "VY Scl"-type variable with V magnitude range 15.8-18.0).
Spectroscopy by E. Aydi et al. (ATel #13867) using the High Resolution Spectrograph (HRS) mounted on the 11m Southern African Large Telescope as part of the SALT Large Science Program on Transients shows a spectrum that resembles that of a classical nova, likely after optical peak. Also, R. Kaufman (Bright, VIC, Australia) reports a low-resolution spectrum obtained by him on 2020 Jul. 16.62 UT (with a Canon 800D camera + 200-mm-f.l. f/3.5 lens) indicates the object to be a "Fe II-type" classical nova.
According to ATel #13868 "the positional coincidence of the optical/gamma-ray transient with the previously known VY Scl-type cataclysmic variable (d = 2.7 kpc from Gaia DR2; Bailer-Jones et al. 2018) suggests that the transient is a Galactic nova, which was confirmed with SALT spectroscopy (ATel #13867). It is only the third time that a classical nova eruption is observed in a previously known white dwarf hosting binary after V407 Cyg (ATel #2487) and V392 Per (ATel #11590), which were also detected by Fermi-LAT."
According to Cbet 4812 "the following pre-discovery V magnitudes from all-sky video images taken by M. A. Phillips at the Edward Pigot Seismic Observatory, Coonabarabran, using a ZWO ASI178MC-COOL color CMOS camera and a 1.4-mm-f.l. f/1.8 fish-eye lens: July 6.81, [6.0; 7.79, [5.5; 8.78, 5.4; 11.76, 3.7; 12.8, 3.8; 13.83, 4.0; 14.8, 4.4; 15.8, 4.7. No variability was seen on single nights. Further CCD magnitudes reported by McNaught from his images: June 30.727, [9.8; July 1.763, [9.9; 2.826, [8.8; 15.747, 5.1; 15.785, 5.1; 15.804, 5.1.
P. Schmeer, Bischmisheim, Germany, reports the following g magnitudes for the nova from the ASAS-SN Sky Patrol: July 2.183, 16.6; 2.186, 16.3; 4.189, 15.5; 8.173, 6.8. Schmeer adds that no previous outbursts or eruptions were recorded in ASAS-SN patrol images since 2014 June 18."
Below our confirmation image. Click on the image for a bigger version:
An animation showing a comparison between my image and the archive POSS2/UKSTU Red plate (1993-12-17).
by Ernesto Guido, Marco Rocchetto & Adriano Valvasori