Cassini’s flyby of Mimas – Part 1

On February 13, 2010, Cassini flew within 9.500 kilometers of Mimas, the closest encounter yet with Saturn’s Death Star-like moon, which averages 396 kilometers in diameter. Cassini approached from the night side and retreated with a nearly full-phase view of Mimas’ leading hemisphere including the giant Herschel Crater. The highest resolution view of Herschel was obtained from a distance of about 15.000 kilometers. Two multispectral mosaics covered most of the visible disk around the crater. One of the last shots caught by Cassini’s camera shows a full-globe Mimas with the limb of Saturn as a backdrop.

High resolution mosaic of Herschel Crater

Four of the highest resolution views from Cassini’s flyby were assembled to this mosaic and show the giant Herschel Crater and its surroundings. The steep slopes of the 140 kilometers wide crater are about 5 kilometers high, and parts of the floor are approximately 10 kilometers deep. The mosaic was rotated to put north up.

Image Credit: NASA/JPL/Space Science Institute/Mosaic by astroarts.org

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Mimas in Color

Cassini was about 71.500 kilometers from Mimas when it captured the images for this false-color composite. Images taken through infrared, blue, and ultraviolet filters produce a view of the moon that emphasizes the interesting bluish-white color splotch on its leading hemisphere, centered on the giant Herschel Crater.

Image Credit: NASA/JPL/Space Science Institute/astroarts.org

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Closeups of Herschel Crater in Color

Images taken through infrared, blue, and ultraviolet filters produce these two detailed false-color views of Herschel Crater. The image on the right shows the southern rim of the crater from a distance of about 15.700 kilometers.

Image Credit: NASA/JPL/Space Science Institute/astroarts.org

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AstroArts – Five Years on the Web!

This website, AstroArts, is now five years old. Five years is a long time – by internet standards it’s like an eternity.
I started conceiving and building the site in late February 2005. Back then the site was located at a free webhosting service with 60 megabytes of storage space. Enough for just a couple of nice picture galleries. But that changed quickly…
On May 12, 2006, I registered the domain astroarts.org with a professional webhosting company whom I still use to this day. The site now uses a blogging model based on WordPress and has articles as its centre rather than just static pages with galleries.

Thanks to all of you for visiting this website during the last five years, and I hope you will continue to enjoy this place just as I do!

Next up will be an article with outstanding pictures from Cassini’s flyby of Saturn’s moon Mimas, which ocurred on February 13, 2010. Stay tuned!

Battered And Cracked-up Dione

Detailed view of the cratered and cracked surface of Dione.

Part of the cratered and cracked surface of Saturn’s moon Dione. The images used for this mosaic are clear-filter views taken by Cassini on January 27, 2010, from a distance of about 45.215 km.

Image Credit: NASA/JPL/Space Science Institute/Mosaic by astroarts.org

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“Wispy Streaks” on Saturn’s moon Rhea

Detailed view
of the wispy trailing hemisphere of Rhea.

The high-resolution images for this 16-frame mosaic across Rhea’s trailing hemisphere were taken by the Cassini spacecraft on November 21, 2009, during its 24.455-kilometer non-targeted encounter with Saturn’s second largest moon. The mosaic shows Rhea’s bright wispy terrain, marked by sets of tectonically formed ice cliffs similar to those of Saturn’s moon Dione, and a part of a large impact basin at the bottom.

Image Credit: NASA/JPL/Space Science Institute/Mosaic by astroarts.org

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Rhea – Crater Upon Crater

Close-up image of Rhea showing numerous craters.

Craters imprinted upon other craters record the long history of impacts endured by Saturn’s moon Rhea. This view looks toward the mid-southern latitudes of the Saturn-facing side of Rhea (1.528 kilometers across). The image was taken by Cassini’s narrow-angle camera on October 13, 2009, from a distance of approximately 45.000 kilometers. Image scale is 262 meters per pixel.

Image Credit: NASA/JPL/Space Science Institute/astroarts.org

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Fog in Valles Marineris

Dense, low lying fog in Valles Marineris.

Image of the western part of Valles Marineris, taken by the High Resolution Stereo Camera (HRSC) on board ESA’s Mars Express spacecraft on May 25, 2004, showing dense ground fog.
This image has not yet been officially released by ESA.

Image Credit: ESA/DLR/FU Berlin (G. Neukum)/astroarts.org

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References:
A. Inada et al.:
Wavelength Dependency and Angular Effects of Reflectance of Fog in Valles Marineris (PDF; 1.7 MB)

A. Inada et al.: Dust Haze in Valles Marineris observed by HRSC and OMEGA onboard Mars Express (PDF; 1.9 MB)

D. Möhlmann: Adsorption water driven processes on Mars (PDF; 1.7 MB)

Chaitén Volcano

Eruption of Chile's Chaitén volcano,
generating a spectacular lightning storm.

Lightning bolts appear above and around the Chaitén volcano in southern Chile as seen from Chana, some 30 kilometers north of the volcano. The mingling of lightning and ash is a so called dirty thunderstorm. These storms may be sparked when rock fragments, ash, and ice particles in the plume collide to produce static charges, just as ice particles collide to create charge in regular thunderstorms.

Image Credit: Carlos Gutierrez/UPI/astroarts.org

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Tethys – Battered and Grooved

Saturn's Moon Tethys from Cassini.

A mosaic of four images of Tethys (1.071 kilometers across) taken on October 14, 2009, with Cassini’s narrow angle camera. The view is towards the Saturn-facing hemisphere.
Near center lies the large crater Penelope, overprinted by many smaller, younger impact sites.
Three smaller impact features of roughly similar size make a line to the right of Penelope. Those craters are (from top) Ajax, Polyphemus and Phemius.

Image Credit: NASA/JPL/Space Science Institute/Mosaic by astroarts.org

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Thaumasia Region

The geology of the Thaumasia region on Mars includes a wide array of rock materials, depositional and erosional landforms, and tectonic structures. The region is dominated by the Thaumasia plateau, which is about 2.900 km across and rises over 4 km above the surrounding terrain. The plateau includes central high lava plains ringed by highly deformed highlands; it may comprise the ancestral center of Tharsis tectonism. The extensive structural deformation of the region, which is without parallel on Mars in both complexity and diversity, occurred largely throughout the Noachian and Hesperian periods (about 4 billion years ago). The deformation produced small and large extensional and contractional structures that resulted from stresses related to the formation of Tharsis, from magmatic-driven uplifts, such as at Syria Planum and central Valles Marineris, and from the Argyre impact. In addition, volcanic, eolian, and fluvial processes have highly modified the older surfaces in this region.

Fractured terrain
of the Thaumasia region.

An escarpment in the center of this picture is at the south extension of the end of Claritas Fossae. The fractures are roughly radial to the Tharsis bulge and cut mostly old cratered terrain. Crater counts indicate that most of the fractures are older than the corresponding fractures north of the Tharsis bulge.

Mosaic of the Viking 1 Orbiter images f057a04 to f057a13, taken on August 17, 1976.
North is at approximately the eleven o’clock position.

Image Credit: NASA/JPL/Arizona State University/Mosaic by astroarts.org

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Dust storm over the Thaumasia region on Mars.

This Viking 2 Orbiter image (f176b02), taken on February 17, 1977, shows a large dust storm over the Thaumasia region on Mars. This large disturbance soon grew into the first global dust storm observed by the Viking Orbiters.
The image covers a region of nearly 1.400 km. North is at approximately the one o’clock position.

Image Credit: NASA/JPL/Arizona State University/astroarts.org

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See also:
ESA – Mars Express – Solis Planum, Thaumasia region

ESA – Mars Express – The grabens of Claritas Fossae

LROC Image Of The Apollo 14 Landing Site #1

LROC NAC image
of the Apollo 14 landing site
and nearby Cone crater.

This picture is a slightly enhanced crop from the original LROC NAC image of the Fra Mauro highlands and shows the Apollo 14 landing site and nearby Cone crater. The faint trails left by the astronauts’ footprints can be clearly seen.

Image Credit: NASA/GSFC/Arizona State University/astroarts.org

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Panorama of Saddle Rock

This panorama, stitched from the Hasselblad photographs AS14-68-9449/50/51 taken by Apollo 14 astronaut Edgar D. Mitchell, shows Saddle Rock, the largest boulder seen during the second extravehicular activity (EVA) of the Apollo 14 mission. Named for its shape, Saddle Rock is 4,5 meters across.

Image Credit: NASA/Panorama by astroarts.org

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Identifying Saddle Rock in the LROC NAC image
of the Apollo 14 landing site.

This picture combines a crop (scaled by a factor of 233 %) from the LROC NAC image of the Apollo 14 landing site with the panorama of Saddle Rock shown above. The arrow points to the location of Saddle Rock at the Apollo 14 geology station C1 near the rim of Cone crater.

Image Credit: NASA/GSFC/Arizona State University/astroarts.org

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