This picture of Venus was taken by the Galileo spacecrafts Solid State Imaging System on
February 14, 1990, at a range of almost 1.7 million miles from the planet. A high pass spatial
filter has been applied in order to emphasize the smaller scale cloud features, and the rendition
has been colorized to a bluish hue in order to emphasize the subtle contrasts in the cloud
markings and to indicate that it was taken through a violet filter. The sulfuric acid clouds indicate
considerable convective activity, in the equatorial regions of the planet to the left and downwind
of the subsolar point (afternoon on Venus). They are analogous to 'fair weather clouds' on Earth.
The filamentary dark features visible in the colorized image are here revealed to be composed of
several dark nodules, like beads on a string, each about 60 miles across. The Galileo Project is
managed for NASA's Office of Space Science and Applications by the Jet Propulsion Laboratory;
its mission is to study Jupiter and its satellites and magnetosphere after multiple gravity assist
flybys at Venus and Earth. These images of the Venus clouds were taken by Galileo's Solid
State Imaging System February 13,1990, at a range of about1 million miles. The smallest detail
visible is about 20 miles. The two right images show Venus in violet light, the top one at a time
six hours later than the bottom one. They show the state of the clouds near the top of Venus's
cloud deck. A right to left motion of the cloud features is evident and is consistent with westward
winds of about 230 mph. The two left images show Venus in near infrared light, at the same
times as the two right images. Sunlight penetrates through the clouds more deeply at the near
infrared wavelengths, allowing a view near the bottom of the cloud deck. The westward motion of
the clouds is slower (about 150 mph) at the lower altitude. The clouds are composed of sulfuric
acid droplets and occupy a range of altitudes from 30 to 45 miles. The images have been spatially
filtered to bring out small scale details and de- emphasize global shading. The filtering has
introduced artifacts (wiggly lines running north/south) that are faintly visible in the infrared
image. The Galileo Project is managed for NASA's Office of Space Science and Applications by
the Jet Propulsion Laboratory; its mission is to study Jupiter and its satellites and
magnetosphere after multiple gravity assist flybys at Venus and Earth.
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