Halo from Atacama
Influenced by the strong Pacific
El
Nino, cloudy skies have more often come to Chile's high
Atacama Desert this season,
despite its reputation as an astronomer's paradise.
Located in one of the driest, darkest places
on planet Earth,
domes of the region's twin 6.5 meter
Magellan telescopes of
Carnegie Las Campanas Observatory were closed on May 13.
Still, a first quarter Moon and bright stars shine through in
this panoramic
night skyscape,
the lunar disk surrounded by a beautiful, bright halo.
The angular radius of the
halo is 22 degrees.
Not determined by the brightness or phase
of the Moon itself, the angle is set by the hexagonal geometry
of atmospheric ice crystals that reflect and refract the moonlight.
On that night, the brilliant star just inside the halo's radius
was really planet Jupiter.
The brightest star flanking the halo to the far left is
Canopus, with
Arcturus on the halo's right.