A total
eclipse of the moon tonight is expected to delight skywatchers across the United States and much of the world.
It will be
the last total lunar eclipse until 2010.
The
easy-to-watch event will play out in several stages as Earth's
shadow blocks sunlight from shining on the moon. Weather permitting, the
eclipse will be visible from all locations in the United States, according to
NASA. Along the Oregon and northern California coasts, the moon will rise
during the early stages of the eclipse, however.
When to
watch
Eclipses
occur only at full moon when the sun, Earth and moon are in a perfect line.
Because the moon's orbit around Earth is not perfectly aligned with the plane
of Earth's orbit around the sun, eclipses do not occur at every full moon.
The moon will enter Earth's umbral
shadow (the full shadow) at 8:43 p.m. ET (that's 7:43 p.m. Central, 6:43 p.m.
Mountain and 5:43 p.m. Pacific) on Wednesday, Feb. 20. It will appear as though
an ever-larger bite is being taken out of the moon.
Some 78
minutes later, the moon will slip into full eclipse. About 51
minutes later, a bright scallop will appear as the moon starts emerging. It
will be completely out of the umbral shadow at 9:09 p.m. Pacific time, which is
12:09 a.m. ET on Thursday morning.
For Europe
and Africa, the eclipse is a predawn Thursday event, with the moon starting
entry to the umbral shadow at 1:43 Greenwich (or Universal) Time.
What
you'll see
Look for
the moon to possibly turn red during the total portion of the eclipse. "The exact color that the moon appears depends on the
amount of dust and clouds in the atmosphere," according to a NASA
statement. "If there are extra particles in the atmosphere, from say a
recent volcanic eruption, the moon will appear a darker shade of red."
The
redness occurs because while the moon is in total shadow, some light from the
sun passes through Earth's atmosphere and is bent toward the moon. The effect
is to cast all
the planet's sunrises and sunsets on the moon.
Christopher
Columbus famously used a blood-red
eclipse in 1504 to frighten natives on Jamaica into feeding his crew.
The planet
Saturn and the bright star Regulus will form a broad triangle with the
moon's ruddy disk, according to Joe Rao, SPACE.com's Skywatching Columnist.
You don't
need any special equipment to watch a lunar eclipse. Comfortable chairs and
warm clothing are good ideas. A telescope will bring out interesting details of
the lunar surface, and even a small telescope will reveal Saturn's stunning
rings.
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