The NASA/ESA/ASI Cassini-Huygens spacecraft has captured the best images so far of Rhea, the fourteenth of Saturn’s known moons.
This mosaic image from the NASA/ESA/ASI Cassini-Huygens spacecraft is centered at 9 degrees north latitude, 254 degrees west longitude. The image was acquired at a distance of about 57,800 km from Rhea. This image represents one of the highest resolution color views of the icy moon released to date, and consists of multiple images from Cassini’s narrow-angle camera (NAC) with data from the wide-angle camera used to fill in areas where NAC data was not available. Image credit: NASA / JPL-Caltech / Space Science Institute.
Saturn has a great many more moons than Earth – a whopping 62. Rhea is the second-largest of Saturn’s moons and the ninth-largest moon in the Solar System.
Discovered on December 23, 1672 by Giovanni Cassini, it is about 1,530 km across – just under half the size of our own Moon.
Rhea takes 4.518 Earth days to rotate around Saturn and to complete one spin on its own axis.
It is one of the oldest and most heavily cratered satellites in the Solar System. Its brightness varies with its position relative to Saturn.
This mosaic image from Cassini-Huygens is centered at 21 degrees north latitude, 229 degrees west longitude. The image consists of multiple images from Cassini’s narrow-angle camera (NAC) with data from the wide-angle camera used to fill in areas where NAC data was not available. It was acquired at a distance of about 78,000 km from Rhea. Image credit: NASA / JPL-Caltech / Space Science Institute.
The two new views of the icy moon were taken about 1.5 hours apart on February 9, 2015, when Cassini was 57,000 to 78,000 km away from Rhea.
Images captured using clear, green, IR and UV spectral filters were combined to create these views, which offer an expanded range of the colors visible to human eyes in order to highlight subtle color differences across the icy moon’s surface.
Both views are orthographic projections facing toward terrain on the trailing hemisphere of Rhea. An orthographic view is most like the view seen by a distant observer looking through a telescope.
After a couple of years in high-inclination orbits that limited its ability to encounter Saturn’s moons, Cassini returned to Saturn’s equatorial plane in March 2015.
The spacecraft’s orbit will remain nearly equatorial for the remainder of 2015, during which it will have four close encounters with Titan, two with Dione and three with Enceladus.
