Comet ISON is to reach its closest point to the Sun tomorrow morning at about 5 am AEDT. At that time it will be 1.9 million km from the centre of the Sun or only 1.2 million km from its visible surface. The comet, or whatever is left of it, will then start its long outward journey back to the Oort cloud at the edge of the solar system.
Comet ISON approaching the Sun. Chart Nick Lomb