V6595 SAGITTARII = NOVA SAGITTARII 2021 No. 2

Following the posting on the Central Bureau's Transient Object Confirmation Page about a possible Nova in Sgr (TOCP Designation: PNV J17581670-2914490) we performed some follow-up of this object through a TEL 0.6-m f/6.5 astrograph + CCD located in the El Sauce Observatory in Chile and operated by Telescope Live network (MPC Code X02).

This transient has been discovered by Andrew Pearce at 8.4 mag (unfiltered) on 2021-04-04.825 UT using a Canon 1100D DSLR camera with a 100mm f/2.8 lens.  Total exposure time was 20 seconds (2 x 10s images stacked). Rob McNaught reported non-detection on 2021-04-02.776 UT (unfiltered limiting mag 11.0).

On images taken on April 06.40, 2021 we can confirm the presence of an optical counterpart with B-filtered CCD magnitude +8.955 (R-filtered & V-filtered images were saturated in 5-second exposures) at coordinates:

R.A. = 17 58 16.08, Decl.= -29 14 56.4

(equinox 2000.0; Gaia DR2 catalogue reference stars for the astrometry).

Our confirmation image (click on it for a bigger version):

An animation showing a comparison between my image and the archive POSS1 plate (1996-09-12). Made with TYCHO software by D. Parrott. Click on it for a bigger version.

According to ATel #14513,  K. Taguchi et al. obtained a spectrum of this transient on 2021-04-05.828 UT using the fiber-fed integral field spectrograph mounted on the 3.8-m Seimei telescope at Okayama Observatory of Kyoto University. Their spectrum shows Balmer lines, Fe II lines, and the Na I D line. According to their spectrum and the brightness, they conclude that this object is a classical nova (with a spectrum similar to those of the slow nova V1280 Sco in the early stage).

Below is part of the discovery image by A. Pearce showing the nova. The bright stars to the top right are gamma 1 and 2 Sgr.  South is to the top and east to the right. (Click on it for a bigger version)

Credit: A. Pearce

This nova has been designated N Sgr 2021 No. 2 (with permanent GCVS designation V6595 Sgr).

by Ernesto Guido, Adriano Valvasori, Marco Rocchetto

NOVA SAGITTARII 2015 No. 3

Following the posting on the Central Bureau's Transient Object Confirmation Page about a possible Nova in Sgr (TOCP Designation: PNV J18033275-2816054) we performed some follow-up of this object remotely through a 0.43-m f/6.8 astrograph + CCD) of  iTelescope network (MPC Code  Q62 - Siding Spring).

On our images taken on September 28.4, 2015 we can confirm the presence of an optical counterpart with R-CCD magnitude 9.5 at coordinates:

R.A. = 18 03 32.77, Decl.= -28 16 05.3

(equinox 2000.0; UCAC4 catalogue reference stars).

Our annotated confirmation image. Click on it for a bigger version:

An animation showing a comparison between my confirmation image and the archive POSS1 Blue plate (1958-04-18). Click on the thumbnail below for a bigger version:

According to CBET nr. 4145, issued on 2015, September 30, , PNV J18033275-2816054 is now NOVA SAGITTARII 2015 No. 3. This nova has been discovered K. Itagaki (Teppo-cho,Yamagata, Japan) on an unfiltered CCD frame taken on Sept. 27.429 UT using a 180-mm-focal-length camera lens.

A spectrogram (resolution about 500 at H-beta) taken of PNV J18033275-2816054 by M. Fujii (Kurashiki, Okayama, Japan) with a 0.4-m telescope on Sept. 27.487 UT shows Balmer emission lines, with the H-beta line having a P-Cyg profile that indicates an expansion velocity of about 1100 km/s.  Emission lines of Fe II (37), (42), and (49) also have P-Cyg profiles.  The Na D absorption is remarkable. (see image below).

Credit: M. Fujii

by Ernesto Guido

Bright Nova in Sgr - (PNV J18365700-2855420)

Following the posting on the Central Bureau's Transient Object Confirmation Page about a possible bright Nova in Sgr (TOCP Designation: PNV J18365700-2855420) we performed some follow-up of this object remotely through a 0.61-m f/6.5 astrograph + CCD) of  iTelescope network (MPC Code  U69 - Auberry, California - USA).

On our images taken on March 16.5, 2015 we can confirm the presence of an optical counterpart with R-CCD magnitude 5.9 at coordinates:

R.A. = 18 36 56.85, Decl.= -28 55 40.0 (equinox 2000.0; UCAC-4 catalogue reference stars).

This nova has been discovered by John Seach, Chatsworth Island, NSW, Australia,  in three images (limiting magnitude 11.0) taken on Mar. 15.634 UT with a digital SLR camera (+ 50-mm-f.l. f/1.0 lens).

Our wide-Field colour image of Nova Sagittarii 2015 No. 2. Details on the caption. Click on the image for a bigger version.

Click on the thumbnail below to see the full wide-field frame with the nova at the center.

Our annotated confirmation image. Click on it for a bigger version.

An animation showing a comparison between our confirmation image and the archive POSS2/UKSTU plate (R Filter - 1996). Our image was obtained when the object was only about +15 degree on the horizon. Click on the thumbnail below for a bigger version:

According to the Atel #7230 "an optical spectrum of PNV J18365700-2855420 (see CBAT TOCP) was obtained using the FRODOspec spectrograph on the Liverpool Telescope at 2015 March 16.27 UT. The spectrum shows strong Balmer series emission exhibiting P Cygni profiles with velocities of ~2800 km/s. Numerous Fe II emission lines (also with P Cygni profiles) are also seen, along with O I, Si II and Mg II features. This confirms that PNV J18365700-2855420 is a bright classical nova of the Fe II spectral type"

by Ernesto Guido & Nick Howes