Comet ISON had a second outburst bringing the magnitude near 4:
According to http://www. spaceweather.com
COMET ISON–ANOTHER OUTBURST? Astronomers working with the TRAPPIST telescope at ESO’s La Silla Observatory report that Comet ISON’s production of gas and dust surged another six-fold during the early hours of Nov. 19th. This marks the second outburst since Nov. 13th. Experienced observers put the comet’s rising magnitude near +4.0, well above the threshold of naked-eye visibility. The problem is, ISON is approaching the sun and becoming increasingly difficult to observe. Shahrin Ahmad of Kuala Lumpur, Malaysia, photographed the comet’s green core framed by twilight blue on the morning of Nov. 19th:
Amateur photography of the comet will be possible for a few more days. Soon, however, only NASA’s fleet of solar observatories will be able to track the sundiver.
At closest approach (perihelion) on Nov. 28th, ISON will be little more than a million kilometers from the sun’s fiery surface. Despite the recent outbursts, which could have been caused by a break up of ISON’s nucleus, astronomers with NASA’s Comet ISON Observing Campaign believe that the comet is still intact. It will need to be to survive next week’s hellish plunge through the sun’s atmosphere.
Observationally speaking, the next big event in the timeline of Comet ISON’s journey comes on Nov. 21st when the comet enters the field of view of STEREO-A. The spacecraft’s Heliospheric Imager will pick up the comet just as Earth-bound telescopes begin to lose it. In the days that follow, STEREO-B, SOHO and the Solar Dynamics Observatory will join the hunt, providing continuous views of Comet ISON all the way to perihelion. Stay tuned for some marvelous images.