Comet Lulin is now a naked eye morning object near Libra headed
toward Virgo. The comet makes its closest approach to Earth (0.41 AU)
on Feb. 24, 2009. Current estimates peg the maximum brightness at 4th
or 5th magnitude, which means dark country skies would be required to
see it. No one can say for sure, however, because this appears to be
Lulin's first visit to the inner solar system and its first exposure
to intense sunlight. Surprises are possible.


Lulin's green color comes from the gases that make up its Jupiter-
sized atmosphere. Jets spewing from the comet's nucleus contain
cyanogen (CN: a poisonous gas found in many comets) and diatomic
carbon (C2). Both substances glow green when illuminated by sunlight
in the near-vacuum of space.


To see Comet Lulin with your own eyes, set your alarm for 3 am. The
comet rises a few hours before the sun and may be found about 1/3rd
of the way up the southern sky before dawn. Here are some dates when
it is especially easy to find:

Feb. 6th: Comet Lulin glides by Zubenelgenubi, a double star at the
fulcrum of Libra's scales. Zubenelgenubi is not only fun to say
(zuBEN-el-JA-newbee), but also a handy guide. You can see
Zubenelgenubi with your unaided eye (it is about as bright as stars
in the Big Dipper); binoculars pointed at the binary star reveal
Comet Lulin in beautiful proximity.

Feb. 16th: Comet Lulin passes Spica in the constellation Virgo. Spica
is a star of first magnitude and a guidepost even city astronomers
cannot miss. A finderscope pointed at Spica will capture Comet Lulin
in the field of view, centering the optics within a nudge of both
objects.

Feb. 24th: Closest approach! On this special morning, Lulin will lie
just a few degrees from Saturn in the constellation Leo. Saturn is
obvious to the unaided eye, and Lulin could be as well. If this
doesn't draw you out of bed, nothing will.