Calendars:Seasons of Ice and Shadow 3
 (Click to order) [edit] Seasons of Ice and Shadow #3[edit] Cassini at Saturn - Double-size Wall CalendarThis is a huge wall calendar, all new for 2008. Click on the thumbnail at right for a larger preview of the entire calendar. For each of the months below, you can click on the large thumbnail to see a quarter-size preview of the actual calendar page, or the small thumbnail to see the original image. |
 (click for larger preview) The actual calendar is printed in glorious detail at 200dpi (3500 x 2300 pixels), on 100 lb cover weight high gloss paper and wire-bound. Each page measures 17" x 11", 17" x 22" when hung on the wall. |
The images have been cropped and rotated where necessary to fit the calendar format. In some cases the colors have been tweaked to bring out the dimmer details in print.
[edit] Cover: Ringworld Family
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A stately Saturn poses for a portrait with five of its moons in this Cassini spacecraft wide angle camera view.
From the left, the moons are Pandora (84 kilometers across, a faint speck near the tip of the rings), Titan (5,150 kilometers across), Enceladus (505 kilometers across), Tethys (1,071 kilometers across), and Janus (181 kilometers across).
Images taken with the Cassini spacecraft wide-angle camera using red, green and blue spectral filters (W00037073-5 and W00037126-8) were composited to create this true-color view. The image was taken on October 27, 2007 at a distance of approximately 1.86 million kilometers from Saturn.
[edit] January: On the Final Frontier
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Saturn sits nested in its rings of ice as Cassini once again plunges toward the graceful giant.
This natural color mosaic was acquired by the Cassini spacecraft as it soared 39 degrees above the unilluminated side of the rings.
Little light makes its way through the rings to be scattered in Cassini's direction in this viewing geometry, making the rings appear somewhat dark compared to the reflective planet. The view can be contrasted with earlier mosaics designed to showcase the rings rather than the planet, which were therefore given longer exposure times (see PIA08362 and PIA08361).
Bright clouds play in the blue-gray skies of the north. The ring shadows continue to caress the planet as they slide farther south toward their momentary disappearance during equinox in 2009. The rings' reflected light illuminates the southern hemisphere on Saturn's night side.
The scene is reminiscent of the parting glance of NASA's Voyager 1 as it said goodbye to Saturn in 1981 (see PIA00335). Cassini, however, will continue to orbit Saturn for many years to come.
Three of Saturn's moons are visible in this image: Mimas (397 kilometers across) at the 2 o'clock position, Janus (181 kilometers across) at the 4 o'clock position and Pandora (84 kilometers across) at the 8 o'clock position. Pandora is a faint speck just outside the narrow F ring.
This mosaic was constructed from wide-angle camera images taken just before the narrow-angle camera mosaic PIA08389. The view combines 45 images -- 15 separate sets of red, green and blue images--taken over the course of about two hours, as Cassini scanned across the entire main ring system. The images in this view were obtained on May 9, 2007, at a distance of approximately 1.1 million kilometers from Saturn. Image scale is about 62 kilometers per pixel.
[edit] February: Approaching Iapetus
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The slim crescent of Iapetus looms before the Cassini spacecraft as it approaches the mysterious moon.
Iapetus, 1,468 kilometers across, seen here in false color, is unique in its dramatic variation in brightness between the northern polar region and the middle and low latitudes. Equally prominent is the moon's equatorial ridge of towering mountains. The profile of the ridge against the darkness of space reveals that it is topped by a cratered plateau approximately 15 kilometers wide. Further west, the profile of the ridge changes from a long plateau to discrete peaks.
The mosaic consists of four image footprints across the surface of Iapetus and has a resolution of 500 meters per pixel. A full-resolution clear filter image was combined with half-resolution images taken with infrared, green and ultraviolet spectral filters (centered at 752, 568 and 338 nanometers, respectively) to create this full-resolution false color mosaic.
The color seen in this view represents an expansion of the wavelength region of the electromagnetic spectrum visible to human eyes. The intense reddish-brown hue of the dark material is far less pronounced in true color images. The use of enhanced color makes the reddish character of the dark material more visible than it would be to the naked eye. In addition, the scene has been brightened to improve the visibility of surface features.
This view was acquired with the Cassini spacecraft narrow-angle camera on Sept. 10, 2007, at a distance of about 83,000 kilometers from Iapetus.
[edit] March: Nature's Canvas
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In a splendid portrait created by light and gravity, Saturn's lonely moon Mimas is seen against the cool, blue-streaked backdrop of Saturn's northern hemisphere.
Delicate shadows cast by the rings arc gracefully across the planet, fading into darkness on Saturn's night side.
The part of the atmosphere seen here appears darker and more bluish than the warm brown and gold hues seen in Cassini images of the southern hemisphere, due to preferential scattering of blue wavelengths by the cloud-free upper atmosphere.
The bright blue swath near Mimas (398 kilometers across) is created by sunlight passing through the Cassini division (4,800 kilometers wide). The rightmost part of this distinctive feature is slightly overexposed and therefore bright white in this image. Shadows of several thin ringlets within the division can be seen here as well. The dark band that stretches across the center of the image is the shadow of Saturn's B ring, the densest of the main rings. Part of the actual Cassini division appears at the bottom, along with the A ring and the narrow, outer F ring. The A ring is transparent enough that, from this viewing angle, the atmosphere and threadlike shadows cast by the inner C ring are visible through it.
Images taken with red, green and blue filters were combined to create this color view. The images were obtained with the Cassini spacecraft narrow angle camera on Nov. 7, 2004, at a distance of 3.7 million kilometers from Saturn. The image scale is 22 kilometers per pixel.
[edit] April: Ringworld Family
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A stately Saturn poses for a portrait with five of its moons in this Cassini spacecraft wide angle camera view.
From the left, the moons are Pandora (84 kilometers across, a faint speck near the tip of the rings), Titan (5,150 kilometers across), Enceladus (505 kilometers across), Tethys (1,071 kilometers across), and Janus (181 kilometers across).
Images taken with the Cassini spacecraft wide-angle camera using red, green and blue spectral filters (W00037073-5 and W00037126-8) were composited to create this true-color view. The image was taken on October 27, 2007 at a distance of approximately 1.86 million kilometers from Saturn.
[edit] May: In Saturn's Shadow
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With giant Saturn hanging in the blackness and sheltering Cassini from the sun's blinding glare, the spacecraft viewed the rings as never before, revealing previously unknown faint rings and even glimpsing its home world.
This marvelous panoramic view was created by combining a total of 165 images taken by the Cassini wide-angle camera over nearly three hours on Sept. 15, 2006. The full mosaic consists of three rows of nine wide-angle camera footprints; only a portion of the full mosaic is shown here. Color in the view was created by digitally compositing ultraviolet, infrared and clear filter images and was then adjusted to resemble natural color.
Interior to the G ring and above the brighter main rings is the pale dot of Earth. Cassini views its point of origin from over a billion kilometers (and close to a billion miles) away in the icy depths of the outer solar system. See PIA08324 for a similar view of Earth taken during this observation.
In this version of the mosaic the color contrast is greatly exaggerated. In such views, imaging scientists have noticed color variations across the diffuse rings that imply active processes sort the particles in the ring according to their sizes. Looking at the E ring in this color-exaggerated view, the distribution of color across and along the ring appears to be different between the right side and the left. Scientists are not sure yet how to explain these differences, though the difference in phase angle between right and left may be part of the explanation. The phase angle is about 179 degrees on Saturn. The main rings are overexposed in a few places.
The mosaic images were acquired as the spacecraft drifted in the darkness of Saturn's shadow for about 12 hours, allowing a multitude of unique observations of the microscopic particles that compose Saturn's faint rings. Ring structures containing these tiny particles brighten substantially at high phase angles: i.e., viewing angles where the sun is almost directly behind the objects being imaged.
During this period of observation Cassini detected two new faint rings: one coincident with the shared orbit of the moons Janus and Epimetheus, and another coincident with Pallene's orbit. (See PIA08322 and PIA08328 for more on the two new rings.) The narrowly confined G ring is easily seen here, outside the bright main rings. Encircling the entire system is the much more extended E ring. The icy plumes of Enceladus, whose eruptions supply the E ring particles, betray the moon's position in the E ring's left-side edge.
This view looks toward the unlit side of the rings from about 15 degrees above the ringplane. Cassini was approximately 2.2 million kilometers from Saturn when the images in this mosaic were taken. Image scale on Saturn is about 260 kilometers per pixel.
[edit] June: Satellite Trio
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This grouping of Dione, Tethys and Pandora near the rings provides a sampling of the diversity of worlds that exists in Saturn's realm. A 330-kilometer-wide impact basin can be seen near the bottom right on Dione (at left). The icy cliffs of Ithaca Chasma can be seen on Tethys (middle, on the far side of the rings). Little Pandora makes a good showing here as well, displaying a hint of surface detail.
Images taken using red, green and blue spectral filters were composited with clear-filter views to create this true-color version of the monochrome image released as PIA07628.
PIA07628 original caption: This excellent grouping of three moons -- Dione, Tethys and Pandora -- near the rings provides a sampling of the diversity of worlds that exists in Saturn's realm.
A 330-kilometer-wide impact basin can be seen near the bottom right on Dione (at left). Ithaca Chasma and the region imaged during the Cassini spacecraft's Sept. 24, 2005, flyby can be seen on Tethys (middle). Little Pandora makes a good showing here as well, displaying a hint of surface detail. Tethys is on the far side of the rings in this view; Dione and Pandora are much nearer to the Cassini spacecraft. Dione is 1,126 kilometers across. Tethys is 1,071 kilometers across and Pandora is 84 kilometers across.
This image was taken in visible blue light with the Cassini spacecraft narrow-angle camera on Sept. 22, 2005, at a distance of approximately 1.2 million kilometers from Saturn. The image scale is about 5 kilometers per pixel on Dione and Pandora and 9 kilometers per pixel on Tethys.
[edit] July: Symmetry in Shadow
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Magnificent blue and gold Saturn floats obliquely as one of its gravity-bound companions, Dione, hangs in the distance. The darkened rings seem to nearly touch their shadowy reverse images on the planet below.
Dione is 1,126 kilometers across. This view looks toward the unlit side of the rings from about 9 degrees above the ring plane. The rings glow feebly in the scattered light that filters through them.
The image was taken in visible light with the Cassini spacecraft wide-angle camera on Feb. 4, 2007, at a distance of approximately 1.2 million kilometers from Saturn. Image scale is 75 kilometers per pixel.
[edit] August: Pastel Planet
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With pastel blues, pinks, greens and golds, Saturn displays a dazzling diversity of colors and hues.
Here, Cassini looks upward at, and through, the sunlit side of the rings from about 19 degrees below the ring plane. The small moon Janus (181 kilometers across) can be spotted off the planet's western limb (edge) near the image bottom.
Images taken using red, green and blue spectral filters were combined to create this natural-color view. The images were obtained with the Cassini spacecraft wide-angle camera on Feb. 3, 2007, at a distance of approximately 1.1 million kilometers from Saturn. Image scale is 60 kilometers per pixel.
[edit] September: The View from Iapetus
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While on final approach for its Sept. 2007 close encounter with Saturn's moon Iapetus, Cassini spun around to take in a sweeping view of the Saturn System. Iapetus (1,468 kilometers across) is the only major moon of Saturn with a significant inclination to its orbit. From the other major satellites, the rings would appear nearly edge-on, but from Iapetus, the rings usually appear at a tilt, as seen here.
Moons visible in this image: Dione (1,126 kilometers across) at left, Enceladus (505 kilometers across) near the left side ansa (or ring edge), Mimas (397 kilometers across) a speck against the ring shadows on Saturn's western limb, Rhea (1,528 kilometers across) against the bluish backdrop of the northern hemisphere, Tethys (1,071 kilometers across) near the right ansa, and Titan (5,150 kilometers across) near lower right. Iapetus was about 30 degrees off the right of the scene.
This natural color mosaic consists of 15 red, green and blue spectral filter images acquired in five wide-angle camera footprints that swept across the scene (Dione and Titan have been shifted inwards to fit on the page). Narrow-angle camera closeups of each of the moons are shown at left. The digitally generated view of Iapetus at right shows it at the same angle and relative size.
The images were obtained on Sept. 10, 2007, at a distance of approximately 3.3 million kilometers from Saturn at a sun-Saturn-spacecraft, or phase, angle of 33 degrees. Image scale is about 195 kilometers per pixel on the planet.
[edit] October: Titan Beyond the Rings
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Cassini delivers this stunning vista showing small, battered Epimetheus and smog-enshrouded Titan, with Saturn's A and F rings stretching across the scene. Epimetheus is 116 kilometers across and giant Titan is 5,150 kilometers across.
The prominent dark region visible in the A ring is the Encke gap (325 kilometers wide), in which the moon Pan (26 kilometers across) and several narrow ringlets reside. Moon-driven features which score the A ring can easily be seen to the left and right of the Encke gap. A couple of bright clumps can be seen in the F ring.
The color information in the colorized view is completely artificial: it is derived from red, green and blue images taken at nearly the same time and phase angle as the clear filter image. This color information was overlaid onto the previously released clear filter view (see PIA07786) in order to approximate the scene as it might appear to human eyes.
The view was acquired with the Cassini spacecraft narrow-angle camera on April 28, 2006, at a distance of approximately 667,000 kilometers from Epimetheus and 1.8 million kilometers from Titan. The image captures the illuminated side of the rings. The image scale is 4 kilometers per pixel on Epimetheus and 11 kilometers per pixel on Titan.
[edit] November: Orb of Ice
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A serene orb of ice is set against the gentle pastel clouds of giant Saturn. Rhea transits the face of the gas giant, whose darkened rings and their planet-hugging shadows appear near upper right.
Rhea is the second largest of Saturn's moons at 1,528 kilometers across. Tiny Janus(181 kilometers across) is visible as a faint speck just below the rings at bottom left, it shadow visible against the blue northern hemisphere at top center. This view looks toward the unilluminated side of the rings from about 3 degrees above the ring plane.
Downloaded images of two quadrants taken using red, green and blue spectral filters were composited to create this hemispheric version of the image released as PIA08366.
The view was acquired with the wide-angle camera on Feb. 4, 2007. Cassini acquired the view at a distance of approximately 1.2 million kilometers from Saturn and 679,000 kilometers from Rhea. Image scale is 68 kilometers per pixel on Saturn and about 40 kilometers per pixel on Rhea.
[edit] December: Rings in Shadow
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Saturn's rings, viewed from their unilluminated side, disappear into the planet's shadow.
Tiny but sunlit Pandora (84 kilometers across) is visible as a faint speck near the top of the image, just outside the narrow F ring.
Saturn's ring system spreads out below Cassini in this night side view. Little light makes its way through the rings to be scattered in Cassini's direction in this viewing geometry.
This natural color mosaic was taken in visible light with the Cassini spacecraft wide-angle camera on December 17, 2006 from a distance of 1.37 million kilometers. (W00020944-50,W00021274)
[edit] About Cassini
The Cassini spacecraft is the first to explore the Saturn system of rings and moons from orbit. Cassini entered orbit on Jun. 30, 2004 and immediately began sending back intriguing images and data. The European Space Agency's Huygens Probe dove into Titan's thick atmosphere in January 2005. The sophisticated instruments on both spacecraft are providing scientists with vital data and the best views ever of this mysterious, vast region of our solar system.
Cassini-Huygens is an international collaboration between three space agencies. Seventeen nations contributed to building the spacecraft. The Cassini orbiter was built and managed by NASA's Jet Propulsion Laboratory. The Huygens probe was built by the European Space Agency. The Italian Space agency provided Cassini's high-gain communication antenna. More than 250 scientists worldwide are studying the data streaming back from Saturn on a daily basis.
The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colo.
- For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov.
- The Cassini imaging team homepage is at http://ciclops.org.
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