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. Earlier this week, the comet's brightening
trend again seemed to be 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 morning — more than six times too dim to be visible to
the unaided eye. But by Wednesday morning, the comet’s brightness had increased
threefold, 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.
"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.
Carl Hergenrother, acting co-coordinator of the comet section of the Association of
Lunar and Planetary Observers, has confirmed Bortle's observations.
Click here for the full story including links to photos of ISON
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