New Comet: C/2015 F4 (JACQUES)

CBET nr. 4085, issued on 2015, March 31, announces the discovery of a comet (magnitude ~16) by C. Jacques on CCD images taken on 2015, March 27.2  by C. Jacques, E. Pimentel and J. Barros with a 0.28-m f/2.2 astrograph at the SONEAR Observatory (Oliveira, Brazil).  The new comet has been designated C/2015 F4 (JACQUES).

We performed follow-up measurements of this object, while it was still on the neocp. Stacking of 14 unfiltered exposures, 60-sec each, obtained remotely on 2015, March 27.7 from Q62 (iTelescope network - Siding Spring) through a 0.43-m f/6.8 astrograph + CCD, shows that this object is a comet with a sharp central condensation surrounded by a coma about 8" in diameter and a tail about 15" long in PA 237.

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

M.P.E.C. 2015-F159 assigns the following preliminary parabolic orbital elements to comet C/2015 F4: T 2015 Aug. 8.20; e= 1.0; Peri. = 31.64; q = 1.73;  Incl.= 47.82

Below you can see the discovery images  (click on it for a bigger version)

Credit: SONEAR Observatory

by Ernesto Guido & Nick Howes

New Comet: C/2015 F2 (POLONIA)

CBET nr. 4083, issued on 2015, March 26, announces the discovery of a comet (magnitude ~17) by R. Reszelewski, M. Kusiak, M. Gedek and M. Zolnowski on CCD images taken on 2015, March 23 with a remote-controlled 0.1-m f/5 astrograph of the Polonia Observatory at San Pedro de Atacama, Chile, in the course of their comet-search program. The new comet has been designated C/2015 F2 (POLONIA).
 

We performed follow-up measurements of this object, while it was still on the neocp. Stacking of 14 unfiltered exposures, 30 seconds each, obtained remotely on 2015, March 23.8 from Q62 (iTelescope network - Siding Spring) through a 0.43-m f/6.8 astrograph + CCD, shows that this object is a comet with ill-defined central condensation surrounded by diffuse irregular coma 15" in diameter.

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

M.P.E.C. 2015-F120 assigns the following preliminary parabolic orbital elements to comet C/2015 F2: T 2015 Apr. 28.77; e= 1.0; Peri. = 351.97; q = 1.21;  Incl.= 28.87

by Ernesto Guido & Nick Howes

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