2017 December 5
A Horizon with Blue and Red
Image Credit & Copyright:
(Planetario Ciudad de La Plata)
What's happening on the horizon?
The horizon itself, past a
spinach field in
shows not only trees but a large volcano: the
Volcán de Fuego (Volcano of Fire).
The red glow at the top of the volcano is hot lava.
eye may also be drawn to the blue circle above the horizon on the left.
This circle surrounds the
together with other colors, is called
A corona is caused by
diffraction of light -- here moonlight -- by small water droplets in the
Earth's intervening atmosphere.
A break in the clouds on the right shows stars and even the
planet Saturn far beyond the volcano.
Although Volcán de Fuego frequently undergoes low-level activity,
the astrophotographer considered himself lucky to capture the scene just during an
explosive eruption in late September.