It's been perhaps the most anticipated astronomical event of the year as Comet ISON makes its way toward the sun on a path and proximity that has some experts believing it might end up as one of the more spectacular comets in a long time.
If all goes right, Comet ISON could be so bright, it would rival a full moon at night and could even be visible during daylight. But that's a big "if".
Right now, we're still in the "drum roll, please" stage as the comet is just days away from its close encounter to the sun after its million year journey from the Oort Cloud.
On Thanksgiving Day, the comet will reach its closest point to the sun (a mere 720,000 miles from the sun) and that's where the drama begins.
The comet will get super bright as it gets super heated from the super sun. Then one of two things will happen: The comet will either break apart from the heat, ending the show and disappointing billions, or it'll survive and have a brilliant glow that some suggest may be so bright, the comet will be visible not only at night, but during the day as well.
Of course, in the Pacific Northwest, getting clear skies in November and December is always a challenge. But lo and behold, we have a couple of clear days and nights in the offing this week -- just in time to see ISON's final days before it makes its sun encounter.
The comet is just barely visible to the naked eye -- a cosmic smudge, but it's there. The trick is, each day that passes closer to Thanksgiving, the comet is getting closer and closer to the sun, making it more difficult to see in darkness as it's rising and setting closer to the sun.
But at least for Wednesday and Thursday nights, you have a chance. Trick is to get up about 90 minutes before sunrise (about 7:17 a.m. in Portland) and look very low in the eastern sky (near where the sun would rise). If you can use a star chart, like Skyviewcafe.com (or smartphone app!) to find Spica, ISON is close by.
Here is a chart for Thursday morning at 5:40 a.m., courtesy of SkyViewCafe.com:
We are, as I said, in a race between seeing ISON when it's still dark as this program indicates the comet rises at 5:25 a.m. on the flat horizon but early morning twilight begins around 5:45-5:50 a.m. Portland also has a challenge in that there are A) city lights and B) mountains to our east. Best plan is to get somewhere dark with a good view to the east/southeast, or cross your fingers that the comet survives Thanksgiving and we get some more clear weather in December and early January.
*If* ISON survives its Thanksgiving encounter with the sun, then it should become brilliantly bright with a long tail as it shows off its heat glow. It'll take while for it to get far enough away from the sun to see at nighttime but by the time we get into mid-late December, ISON should be above the horizon for much -- if not all -- of the nighttime hours. ISON makes its closest pass to Earth on its return trip out on Dec. 26 and sure enough, SkyViewCafe says the comet will be visible all of Christmas Eve Night and Christmas Night.
ISON will stay above the horizon at night into January and February, but will be getting increasingly dim as the comet moves further away from Earth.
Happy comet hunting!
NASA: Timeline of Comet ISON's Dangerous Journey
Huffington Post: How to see Comet ISON this week: Nov. 18-24
Space.com: Potentially Dazzling Comet ISON Now Visibile To Naked Eye After Outburst