Get ready for a stellar show. The much-anticipated Comet ISON is now visible to the naked eye according to reports from many observers.
Comet ISON — the potential “comet of the century” — has suddenly brightened in an outburst of activity with just two weeks to go before it literally grazes the surface of the sun.
In recent months, Comet ISON has repeatedly befuddled forecasters trying to anticipate just how bright it will ultimately become. But earlier this week, the comet’s brightening trend again seemed to sputtering and stalling, but more recent observations suggest a sudden and radical upsurge in brightness. [Photos of Comet ISON: A Potentially Great Comet]
Comet ISON Lightens Up, Literally
Comet ISON is now in full outburst mode, becoming many times brighter over just the past few days. Astronomers measure the brightness of objects in the night sky as magnitude, in which the brighter an object is, the lower its magnitude number. The human eye can perceive objects as faint as magnitude +6.5.
According to veteran comet observer, John Bortle, Comet ISON was shining only at magnitude +8.5 on Monday (Nov. 11) morning — more than six times too dim to be visible to the unaided eye. But by Wednesday morning, the comet’s brightness had increased three-fold brightening to +7.3. [8 Essential Facts About Comet ISON]
If that was a surprise, an even bigger one was waiting for Bortle on Thursday morning (Nov. 14).
“Ready to go at 4:45 a.m. but I couldn’t figure out what the funny-looking, blotted, star that came into view was,” Bortle said. “(Was my) seeing that bad? But, no, the ‘blotted star’ was, in fact, at the comet’s position! Getting to the point, the little but intensely condensed, globular cluster-looking comet was a whopping magnitude 5.4 — two full magnitudes brighter than just 24 hours ago! This makes for a three magnitude total rise since my observation on Monday.”
In just 72 hours, Comet ISON increased nearly 16 times in brightness.