The Moon blots out part of the Sun as it transits between the star and
cameras aboard one of NASA's STEREO probes
The Moon blots out part of the Sun as it transits between the star and cameras aboard one of NASA's
STEREO probes.
In this set
of images, taken by NASA’s STEREO B
spacecraft, the Moon passes in front of the Sun during a Feb. 25, 2007 transit
in an appetizer of sorts for a March 3 lunar
eclipse that dazzled skywatchers on Earth [New
Images].
[Click
here for video of STEREO’s lunar transit of the Sun.]
STEREO,
short for Solar Terrestrial Relations Observatory, is a NASA mission aimed at
building three-dimensional images of the Sun using two nearly identical probes –
STEREO A and STEREO B – with one leading the Earth’s orbit (STEREO A) and the
other trailing aft of the planet (STEREO B).
It was
STEREO B that caught the Moon’s transit across the Sun. The probe is separated from
Earth by a distance of about 1 million miles (1.6 million kilometers), and is
about 4.4 times farther away from the Moon than Earth observers.
As a
result, the Moon appears 4.4 times smaller in this transit. It is only from
Earth that orbital mechanics conspire to provide solar eclipses in which the
Moon’s disc can completely obscure the Sun. The Moon does remain much larger
than the discs of both Venus
and Mercury
[IMAGES],
planets that have transited the Sun in the last few years.
The Feb. 25
event began at 1:56 a.m. EST (0556 GMT) and ran about 12 hours, concluding at
about 1:57 p.m. EST (1757 GMT).
The images
seen by STEREO B above are actually a combination of observations taken in four
different wavelengths of extreme ultraviolet light. They were released after
researchers unveiled a stunning STEREO
panorama last week that spanned the 93 million miles (150 million
kilometers) between the Sun and Earth’s orbit [image].
-- Tariq Malik
Credit: NASA/GSFC
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