A visitor is making its way through the solar system for the first time and astronomers wonder if it's heading for a fiery rendez-vous with the sun.

Comet ISON watcher

Amateur astronomer Don Kelly of Oromocto will be hoping for another glimpse of Comet ISON on Thursday. (CBC)

Amateur astronomer Don Kelly was up before dawn Wednesday scanning the pre-dawn skies for the Comet ISON, which is throwing out a long glowing tail as it heads toward the sun.

"Comet ISON has gone through a radical change right now," said Kelly. "Something has happened. They're not sure if there's been kind of an explosion or fragmentation that has gone on in the head of the comet. It has radically brightened."

It's now bright enough to be visible through binoculars just before the sun rises over the horizon. On Tuesday, Kelly used binoculars to spot ISON as it moved between the planet Mercury and the star Spica, which is the brightest star in the constellation Virgo.

"I only found the fuzzy ball," said Kelly, who estimated he was able to follow ISON for less than five minutes.

"I didn't have a tripod, but there was certainly no problem telling this was a nebula, or coma, or head of the comet."

Comet Ison

Comet ISON (C/2012 S1) captured by the Mount Lemmon SkyCenter using the 0.8m Schulman Telescope and an STX-16803 CCD camera on Oct. 8, 2013. (Adam Block/Mount Lemmon SkyCenter/University of Arizona)

Time is elapsing for sky-watchers to get a glimpse of ISON on its journey toward the sun. The comet will become harder to see as it draws nearer to the sun and is scheduled to whip around the sun on Nov. 28.

"It'll get to the sun and soon we won't be able to see it anymore," said Kelly, who hopes to get another look at ISON before dawn on Thursday.

"It'll take its very close grazing around the sun and be thrown back out the other way, which it will come closer to earth."

There is also some suspense in ISON's journey. It could break up as it approaches the sun, or could have its ice and dust burned off. Kelly says if it survives, ISON could be spectacular.

"We're anticipating that this could possibly be the comet of the century," he said.