So here is the hype on ISON: On November 28, it is expected to dive into the sun's atmosphere. If it survives, it might glow as brightly as the moon and be briefly visible in daylight. Its tail might stretch far across the night sky.

Battams is optimistic, but he said we won't know until late summer what to expect from ISON.

"I'll be surprised if we don't have a bright comet this fall and/or winter, but it's still just too early to speculate," he said.

So, like Pan-STARRS, ISON's fate will be decided by the sun. It could burn brightly and earn that "Comet of the Century" title; it could melt or it could just break apart.

Scientists say neither comet poses any threat to Earth, but if both comets hold together, sky watchers will get a rare treat: two comets, both bright enough to be seen with the naked eye, in one year.

Fingers crossed!