Comet ISON has just entered the field of view of LASCO C2. At 1300 UTC Comet ISON was 7.5 R_sun from the center of the Sun, or 6.5 R_sun from the surface. It is nearing the point where the solar heating can evaporate the small particles, converting them to molecules and atoms, and causing the dust tail to disappear.
Still looking good. Moving toward perihelion this afternoon. It is 6.5 R_sun from the the center of the Sun (5.5 R_sun above the surface.) This is only 3.8 million km (2.4 million miles) above the surface of the Sun. For those keeping track, Comet ISON moved 700,000 km (430,000 miles) closer to the Sun in a little over an hour.