Explanation:
A quest
to find planet Earth's darkest night skies led to this
intriguing panorama.
In projection, the mosaic view sandwiches the horizons visible
in all-sky
images taken
from the northern hemisphere's Canary Island of La Palma (top)
and the south's high Atacama Desert
between the two hemispheres of the Milky Way Galaxy.
The photographers' choice of locations offered locally dark skies enjoyed
by La Palma's
Roque de
los Muchachos Observatory and
Paranal Observatory
in Chile.
But it also allowed the directions to
the
Milky Way's north
and south galactic poles to be placed near the local zenith.
That constrained the faint, diffuse glow of the plane of the
Milky Way to the mountainous horizons.
As a result, an even fainter S-shaped band of light, sunlight
scattered
by dust along the solar system's
ecliptic plane,
can be completely traced through both northern and southern
hemisphere night skies.
