Tuesday, January 31, 2012

Saturn and Dione


Saturn and Dione appear askew in this Cassini spacecraft view, with the north poles rotated to the right, as if they were threaded along on the thin diagonal line of the planet's rings.

This view looks toward the anti-Saturn side of Dione (698 miles, or 1,123 kilometers across). North on Dione is up and rotated 20 degrees to the right. This view looks toward the northern, sunlit side of the rings from less than one degree above the ring plane.

The image was taken in visible green light with the Cassini spacecraft wide-angle camera on December 12, 2011. The view was obtained at a distance of approximately 35,000 miles (57,000 kilometers) from Dione and at a Sun-Dione-spacecraft, or phase, angle of 41 degrees. Image scale is 2 miles (3 kilometers) per pixel on Dione.

Photo credit: NASA/JPL-Caltech/Space Science Institute

Wednesday, January 25, 2012

Dune Fields on Titan and Earth


Two different dune fields on Titan: Belet (top left) and Fensal (bottom left), as imaged by Cassini's radar. The image also shows two similar dune fields on Earth in Rub Al Khali, Saudi Arabia.

Fensal is at higher latitude and elevation than Belet and clearly shows thinner dunes with brighter and wider areas in between, suggesting less abundant dune material in this region.

Photo credit: NASA/JPL-Caltech/ASI/ESA and USGS/ESA

Note: For more information, see Cassini's Radar Observes Titan's Tropical Dune Fields; also, PIA15225: Dune Patterns.

Tuesday, January 24, 2012

Mimas Behind Dione


Saturn's moon Mimas peeks out from behind the night side of the larger moon Dione in this Cassini image captured during the spacecraft's December 12, 2011, flyby of Dione.

Dione is 698 miles, or 1,123 kilometers, across and its day side dominates the view on the right of the image. Smaller Mimas is on the left and measures 246 miles, or 396 kilometers, across.

Lit terrain seen here is on the Saturn-facing side of Mimas and in the area between the trailing hemisphere and anti-Saturn side of Dione. North on the moons is up and rotated 20 degrees to the right.

The image was taken in visible light with the Cassini spacecraft narrow-angle camera. The view was obtained at a distance of approximately 58,000 miles (94,000 kilometers) from Dione and at a Sun-Dione-spacecraft, or phase, angle of 42 degrees. Image scale is 1,833 feet (559 meters) per pixel on Dione. The view was obtained at a distance of approximately 380,000 miles (611,000 kilometers) from Mimas and at a Sun-Mimas-spacecraft, or phase, angle of 41 degrees. Image scale is 2 miles (3 kilometers) per pixel on Mimas.

Photo credit: NASA/JPL-Caltech/Space Science Institute

Tuesday, January 17, 2012

Closest Flyby of Dione


Flying past Saturn's moon Dione, Cassini captured this view which includes two smaller moons, Epimetheus and Prometheus, near the planet's rings.

The image was taken in visible light with Cassini's narrow-angle camera during the spacecraft's flyby of Dione on December 12, 2011. This encounter was the spacecraft's closest pass of the moon's surface, but, because this flyby was intended primarily for other Cassini instruments, it did not yield Cassini's best images of the moon. Higher resolution images were obtained during earlier flybys (see PIA07638).

Dione (698 miles, or 1,123 kilometers across) is closest to Cassini here and is on the left of the image. Potato-shaped Prometheus (53 miles, or 86 kilometers across) appears above the rings near the center top of the image. Epimetheus (70 miles, or 113 kilometers across) is on the right.

This view looks toward the northern, sunlit side of the rings from less than one degree above the ring plane. The view was acquired at a distance of approximately 67,000 miles (108,000 kilometers) from Dione. Image scale is 2,122 feet (647 meters) per pixel on Dione.

Photo credit: NASA/JPL-Caltech/Space Science Institute

Wednesday, January 11, 2012

Titan and Tethys Behind the Rings


The line of Saturn's rings disrupts the Cassini spacecraft's view of the moons Tethys and Titan.

Larger Titan (3,200 miles, or 5,150 kilometers across) is on the left. Tethys (660 miles, or 1,062 kilometers across) is near the center of the image. This view looks toward the Saturn-facing sides of Tethys and Titan. The angle also shows the northern, sunlit side of the rings from less than one degree above the ring plane.

The image was taken in visible red light with the Cassini spacecraft narrow-angle camera on December 7, 2011. The view was acquired at a distance of approximately 1.4 million miles (2.2 million kilometers) from Tethys and 1.9 million miles (3.1 million kilometers) from Titan. Image scale is 8 miles (13 kilometers) per pixel on Tethys and 12 miles (19 kilometers) on Titan.

Photo credit: NASA/JPL-Caltech/Space Science Institute

Tuesday, January 3, 2012

Saturn and Tethys


Saturn's moon Tethys orbits in front of the wide shadows cast by the rings onto the planet for this Cassini spacecraft view.

Tethys (660 miles, or 1,062 kilometers across) appears just below the rings near the center of the image. This view looks toward the northern, sunlit side of the rings from less than one degree above the ring plane.

The image was taken with the Cassini spacecraft wide-angle camera on December 7, 2011 using a spectral filter sensitive to wavelengths of near-infrared light centered at 752 nanometers. The view was obtained at a distance of approximately 1.1 million miles (1.8 million kilometers) from Tethys. Image scale is 66 miles (107 kilometers) per pixel on Tethys.

Photo credit: NASA/JPL-Caltech/Space Science Institute