[Illustration: 11/5/80 9 million km (5.5 million mi)
Saturn is the sixth planet from the Sun and second largest in our
solar system. Like Jupiter, it is a giant sphere of gas—mostly
hydrogen and helium—with a possible core of rocky material. Various
features in Saturn’s cloudtops are visible in the accompanying
color-enhanced image of the planet’s northern hemisphere:
small-scale convective cloud features (similar to, but much larger
than, thunderstorms in Earth’s atmosphere) are visible in the brown
belt; an isolated convective cloud with a dark ring is visible in
the light brown zone; and a longitudinal wave is visible in the
light blue region.]
[Illustration: 9/17/80 76 million km (47 million mi)
As Voyager 1 approached Saturn, a series of dark and light cloud
bands (belts and zones) became apparent in the planet’s northern
hemisphere through a high altitude atmospheric haze. The planet’s
shadow obscures the rings behind and immediately to the east of the
disk. In addition, the shadow of the rings on the planet’s disk can
be seen just north of the rings themselves as they cross in front of
the planet. Six of Saturn’s 15 known satellites are visible.
Saturn’s largest moon, Titan (considerably larger than Earth’s
moon), is clearly visible in the upper left corner. The smaller
satellites Dione, Tethys, and Rhea are shown in the lower left
corner (upper, middle, and lower, respectively). Two of the
innermost moons, Mimas and Enceladus, appear to the right of the
planet (Mimas is the one closer to the planet). These six moons
orbit Saturn in the equatorial plane and appear in their present
positions because Voyager is above that plane.]
[Illustration: 10/18/80 34 million km (21 million mi)
The North Temperate Belt is visible as the violet-colored belt in
this false-color photograph. In this image, features which are
especially bright in ultraviolet light appear as turquoise and
violet, while ultraviolet-dark areas appear orange. Notice in
particular the three spots (two bright orange and one pale violet)
at mid-northern latitudes. The bright spots are similar to those
shown at much higher resolution in later images. The distinct color
difference between the North Equatorial Belt and Saturn’s other
belts and zones may be due to a thick haze layer covering the
northern portion of the belt. It is not yet understood why the
southern hemisphere of the planet (below the rings) appears bluer
than the northern hemisphere. Color spots in the rings are artifacts
of image processing.]
[Illustration: 10/30/80 18 million km (11 million mi)
Saturn’s soft, velvety appearance and previously unseen detail in
its mysterious rings became visible as Voyager 1 approached the
planet. For example, a gap in the dark C-Ring is now visible, and
material can be seen within the relatively wide Cassini Division
(long believed to be empty), which separates the B-Ring (middle)
from the A-Ring (outer). The Encke Division appears near the outer
edge of the A-Ring. Detail can be seen within the shadow cast by the
rings upon the planet: the broad, dark band near the equator is the
shadow of the B-Ring; the thinner, brighter line just to the south
is the shadow of the less dense A-Ring. Three of Saturn’s moons,
Tethys (outer left), Enceladus (inner left), and Mimas (right) are
also visible in this computer mosaic of Voyager 1 images.]
[Illustration: 11/6/80 8.5 million km (5.3 million mi)
An unusual red oval cloud feature, similar to (but smaller than)
Jupiter’s Great Red Spot, was discovered in the southern hemisphere
of Saturn. The oval, 6000 kilometers (4000 miles) in length, is
located at 55 degrees south latitude. The difference in color
between the red oval and the surrounding bluish clouds in these two
false-color images indicates that material within the oval contains
a substance that absorbs more blue and violet light than the bluish
clouds. Voyager scientists first observed the oval in August 1980,
and the feature has retained its appearance since its discovery.]
[Illustration: 11/6/80 8 million km (5 million mi)
In this photograph, the shadow of the satellite Dione is seen as a
dark circle on the face of the planet.]
[Illustration: 11/10/80 3.5 million km (2.2 million mi)
A ribbon-like wave structure and small convective features marking a
westward jet stream above the wave are visible in this photograph of
Saturn’s cloudtops. The view, extending from 40 degrees to 60
degrees north latitude, shows features 65 kilometers (40 miles) in
diameter. Measurements in images such as this one indicate that
Saturn has fewer east-to-west wind currents than does Jupiter.]
[Illustration: 11/12/80 442,000 km (265,000 mi)
Numerous small cloud features were photographed as Voyager 1 passed
above Saturn’s southern hemisphere. At these polar latitudes, the
large-scale light and dark bands break down into small-scale
features, seen here as waves and eddies.]
[Illustration: 11/7/80 7.5 million km (4.6 million mi)
Two brown ovals, approximately 10,000 kilometers (6000 miles)
across, were discovered in Saturn’s northern hemisphere, at about 40
degrees and 60 degrees latitude. The polar oval (upper left) has a
structure similar to Saturn’s red oval located in the southern polar
latitudes. Detail within the ovals is not visible at this
resolution, so it is not yet known if they are rotating features
similar to the many spots in Jupiter’s atmosphere.]