Credit & Copyright: Henrik Adamsson
Explanation:
The striking X in this
lunarscape
is easily visible in binoculars or a small telescope,
but not too many have seen it.
The catch is, this lunar
X
is fleeting and only apparent
in the hours before the Moon's
first quarter phase.
Along the shadow line between lunar day and night,
the X illusion is produced by a configuration of craters seen
here toward the left,
Blanchinus, La Caille and Purbach.
Near the Moon's first quarter phase, an
astronaut standing close to
the craters' position would see the slowly rising Sun very
near the horizon.
Temporarily, crater walls would be in sunlight
while crater floors would still be in darkness.
Seen from planet Earth,
contrasting sections of bright walls against
the dark floors by chance look remarkably like an X.
This sharp image of the Lunar X was captured on February 22nd.
For extra
credit, sweep your gaze along the lunar terminator and
you can also spot the Lunar
V.
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NASA Web Site Statements, Warnings, and Disclaimers
NASA Official: Jay Norris. Specific rights apply.
A service of: LHEA at NASA / GSFC
& Michigan Tech. U.
|
Публикации с ключевыми словами:
Moon - Луна - Терминатор
Публикации со словами: Moon - Луна - Терминатор | |
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