Tuesday, October 27, 2009

Murky Views of Umbriel

When Voyager 2 flew by Uranus in 1986, the extreme tilt of Uranus, the "planet on its side," and the need to continue on to Neptune meant that it would not be able to fly close to all of the planet's major moons, because it would make its closest approach to all of them at about the same time.  Additionally, the best images of Umbriel are smeared. 

While Umbriel is black as a lump of coal, a bright spot can be seen in a large basin near the terminator in this distant view.

In this view, Umbriel has rotated significantly, but because the south pole is pointed almost straight at the spacecraft, it appears to rotate like a pinwheel.  More features can been, including the fact that the basin seen earlier is a double basin.  A large lineament can be seen just to the lower right of the center of the disk.
This view is the closest color view of Umbriel (the closest view is colorized based on this image).   Thank to spacecraft motion, the phase angle is growing, and the heavily cratered, dark moon can be seen to have several bright spots, most notably the extremely bright crater rim near the top of the disk, Wunda.

This is Voyager's best view of Umbriel and its cratered surface. It appears that their is a degraded tectonic feature near the bottom of the terminator.  Wunda sits prominently at the top of the disk, and another crater, Skynd, on the upper terminator lacks a bright rim but has a bright central peak.

This view of Wunda, produced using the last two images shown here and reprojected to be seen as if viewed from above, shows the doughnut-like shape (with a tiny segment missing pointing diagonally down and left).


While of very limited quality, this crescent image, taken as Voyager receded, speaks to the rugged surface of this battered moon via its lumpiness.  A bright spot can be seen toward the bottom of the crescent, possibly another bright spot. 

Processed Images Copyright Ted Stryk, Raw Data Courtesy NASA/JPL

Friday, October 23, 2009

Thebe from Galileo

Thebe, with a mean diameter of about 100 kilometers, is the second largest of Jupiter's small inner moons.  It was discovered by Voyager 1 during its approach to the planet in 1979.  The image below contains all the images Galileo obtained.  The closest view (third column, middle row) as a resolution of 2 km/pixel, nominally better than the best view of the largest inner moon, Amalthea, although this image is incredibly noisy, rendering an effective resolution somewhat poorer.

Galileo obtained a color view on its fourth orbit, showing Thebe to have a reddish color.

Here is a combination of the color data with the closest image.

Processed images Copyright Ted Stryk, Raw Data Courtesy NASA/JPL

Tuesday, October 13, 2009

Spirit's Heat Shield

This is an super-resolution image of Spirit's Heat Shield taken in 2004 on sol 82. It has been combined with color data from Sol 80.

Processed images Copyright Ted Stryk, Raw Data Courtesy NASA/JPL

Wednesday, October 07, 2009

Ganymede and Io

This image shows a crescent of the Jovian moons Ganymede (larger) and Io (smaller) from the Galileo spacecraft.  The color is an overlay using data from other orbits.

Processed images Copyright Ted Stryk, Raw Data Courtesy NASA/JPL

Friday, October 02, 2009

A Collection of Lunar Images From Planetary Missions

This is a collection of lunar images taken by spacecraft not normally associated with the moon.  It is far from comprehensive, but provides an interesting sampling.

First is an image taken by Deep Impact in February of 2005, showing Mare Orientale on the terminator.  It has been deconvolved to reduce the effects of Deep Impact's camera being out of focus.

This is another view showing Mare Orientale and taken in 2005.  It was taken by the Messenger spacecraft on its way to study Mercury.

This image is a distant view from January of 1998.  It was taken by the Near Earth Ateroid Rendezvous (NEAR) spacecraft during a flyby of the earth.   NEAR was looking down on the south pole.
The final image was taken by the Stardust spacecraft during its earth flyby in January 200l, looking down on the north side. Unfortunately, Stardust suffered from a foggy camera (a problem that was largely resolved before its comet flyby.  Here is the version of the image on the Stardust website http://stardust.jpl.nasa.gov/photo/lunar.jpg  
Here is amy version of the image, with the fog removed.
 Processed images Copyright Ted Stryk, Raw Data For Stardust and Deep Impact Courtesy NASA/JPL, Raw Data for Messenger and NEAR Courtesy NASA/JHU/APL