As planet Earth approached the plane of the
Comet PanSTARRS (C/2011 L4) orbit on May 23rd, comet watchers were
to this view of its
The long, narrow anti-tail stretches
to the right across this frame for nearly 4 degrees
or about 8 times the angular size of the full Moon.
The tail trails along the comet's orbit as it
leaves the inner solar system behind.
An almost edge-on perspective from near the outbound
comet's orbital plane
enhances the view of the anti-tail and
makes it seem to point in the sunward direction,
only apparently contrary to the
behavior of comet dust tails
pushed outward by the pressure of sunlight.
Sweeping far north in planet Earth's skies,
the comet is up all night for most of the northern hemisphere,
but now bright moonlight interferes with its visibility.
PanSTARRS anti-tail is one of the longest since the appearance of