Space Station Crew to View Solar Eclipse
Image: Cosmonauts onboard space station Mir photographed
the Moon’s shadow on Earth during the August 11, 1999, total
solar eclipse. [more]
From Africa to Australia, all eyes will be on the
sky this Wednesday, Dec. 4th, when the moon glides in front of
the sun. It’s a total solar eclipse–the only one this year–and
millions of people will be watching.
On the International Space Station (ISS), people will be watching,
too. But everyone there will be looking down.
"The space station won’t be inside the path of totality,"
explains NASA’s Rob Suggs, the leader of the Space Environments
Team at the Marshall Space Flight Center. "But the crew
will have a great view anyway. They’ll be able to see the moon’s
shadow–a big dark spot on the earth below."
Total solar eclipses happen somewhere on Earth about once
each year. This one takes place entirely in the southern hemisphere.
It begins at 0550 UT on Dec. 4th when the Moon’s shadow falls
on the Atlantic Ocean near southern Africa.
The shadow moves fast, about 2000 km per hour. It will race
across five African countries in only 30 minutes. Alert sky watchers
in Angola, Namibia, Botswana, Zimbabwe and Mozambique can see
the eclipse just after local sunrise.
By 0630 UT, the shadow will be in the Indian Ocean and heading
for Australia, where observers will later watch the eclipse around
sunset. It takes 3 hours for the shadow to cross the ocean. Not
many people will see it during that time … except the crew
of the space station.
"The ISS circles the earth every 90 minutes; it will
fly over the Indian Ocean three times during the eclipse,"
says Suggs. "At 0756 UT, anyone looking out the station’s
starboard-side windows should be able to see the moon’s shadow
near the earth’s limb."
The station’s new science officer, Don Pettit, will surely
be watching. He’s an amateur astronomer and an avid astrophotographer.
"He’ll try to photograph the shadow and maybe even capture
it on video," says Suggs, who’s helping Pettit figure out
when and where to look.
Pettit’s photos will capture both parts of the moon’s shadow:
Innermost is the umbra, an 80 km-wide region as dark
as night. Anyone standing in the umbra’s path, called the "path
of totality," experiences something unforgettable. Strange
banded shadows ripple across the ground just before the sun disappears.
Birds stop singing. Bees stop buzzing. The ghostly solar corona
springs into view and spreads across the sky. For some sky watchers
beholding their first eclipse, it’s a life-altering experience.
They become thereafter dedicated eclipse-chasers.
Surrounding the umbra is the penumbra–a vast region
of gray shadow where the Sun is only partially covered. Sky watchers
inside the penumbra, which is thousands of kilometers wide, can
look up and see a crescent-shaped sun. (Note: Never look directly
at the sun–even an eclipsed sun–without suitable eye
protection.) It’s more fun, however, to look down at the
ground where sunbeams passing through, e.g., window slats
or tree leaves make curved splashes of light.
The station itself will be inside the penumbra for about 10
minutes. During that time astronauts looking out the windows
might see crescent-shaped sunbeams playing across the station’s
outer hull. "The ISS is put together something like an erector
set," explains Suggs. There are plenty of criss-crossing
structures that naturally cast beams of light–perfect for observing
a partial eclipse.
But the real attraction isn’t a sunbeam. You can enjoy those
on Earth. For the crew of the ISS, the highlight of this eclipse
will be a great big shadow–as only they can see it.
Will you be stuck on Earth during the Dec. 4th eclipse?
Check out these viewing
tips from NASA.
