Cbet nr. 3238, issued on 2012, September 24, announces the discovery of a new comet (discovery magnitude 18.8) by Vitali Nevski (Vitebsk, Belarus) and Artyom Novichonok (Kondopoga, Russia) on CCD images obtained on Sept. 21.06 UT with a 0.4-m f/3 Santel reflector of the International Scientific Optical Network (ISON) near Kislovodsk, Russia. The new comet has been designated C/2012 S1 (ISON).

Comet C/2012 S1 (ISON) will get to within 0.012AU of the Sun (extremely close) at the end of November 2013 and then to ~0.4AU from Earth at the beginning of January 2014! According to its orbit, this comet might become a naked-eye object in the period November 2013 - January 2014. And it might reach a negative magnitude at the end of November 2013.

We performed some follow-up measurements of this object, while it was still on the neocp. Stacking of 24 unfiltered exposures, 120-sec each, obtained remotely on 2012, September 22.4 from H06 (ITelescope network near Mayhill, NM) through a 0.25-m, f/3.4 reflector + CCD, shows that this object is slightly diffused, with a 5" coma. The FWHM of this object was measured about 15% wider than that of nearby field stars of similar brightness.

Our confirmation image
C/2012 S1
© Remanzacco Observatory
Here you can see an animation showing the movement of the comet in about 30 minutes

M.P.E.C. 2012-S63 assigns the following nearly parabolic (e = 0.999999964) orbital elements to comet C/2012 S1 (ISON): T 2013 Nov. 28.87; e= 0.99; Peri. = 345.56; q = 0.012 AU; Incl.= 62.36.

Below you can see a graph generated using the software Orbitas and showing the predicted magnitude (in red) versus the elongation (click on the image for a bigger version):
C/2012 S1 Magnitude
© Remanzacco Observatory
Ephemeris for this comet can be seen here.