All posts by Tom

Saturn in Methane

saturnmethane

When viewed through a methane filter the banding on Saturn really stands out.

The Cassini caption:
The soft, bright-and-dark bands displayed by Saturn in this view from NASA’s Cassini spacecraft are the signature of methane in the planet’s atmosphere.

This image was taken in wavelengths of light that are absorbed by methane on Saturn. Dark areas are regions where light travels deeper into the atmosphere (passing through more methane) before reflecting and scattering off of clouds and then heading back out of the atmosphere. In such images, the deeper the light goes, the more of it gets absorbed by methane, and the darker that part of Saturn appears.

The moon Dione (698 miles or 1,123 kilometers across) hangs below the rings at right. Shadows of the rings are also visible here, cast onto the planet’s southern hemisphere, in an inverse view compared to early in Cassini’s mission at Saturn (see PIA08168).

This view looks toward the unilluminated side of the rings from about 0.3 degrees below the ringplane. The image was taken with the Cassini spacecraft wide-angle camera on Sept. 6, 2015, using a spectral filter which preferentially admits wavelengths of near-infrared light centered at 728 nanometers.

The view was acquired at a distance of approximately 819,000 miles (1.32 million kilometers) from Saturn. Image scale is 49 miles (79 kilometers) per pixel. Dione has been brightened by a factor of two to enhance its visibility.

The Night side of Charon

charonnightside

Who would have guessed that not only would we see Pluto’s Charon, but the night side of the moon too?! Ok NASA would.

Here’s what the New Horizons had to say about the image:
After its close approach to Pluto in July 2015, NASA’s New Horizons spacecraft snapped this hauntingly beautiful image of the night side of Pluto’s largest moon, Charon.

Only an imager on the far side of Pluto could catch such a view, with a bright, thin sliver of Charon near the lower left illuminated by the sun. Night has fallen over the rest of this side of Charon, yet despite the lack of sunlight over most of the surface, Charon’s nighttime landscapes are still faintly visible by light softly reflected off Pluto, just as “Earthshine” lights up a new moon each month. Charon is 750 miles (1,214 kilometers) in diameter, approximately as wide as Texas.

Scientists on the New Horizons team are using this and similar images to map portions of Charon otherwise not visible during the flyby. This includes Charon’s south pole – toward the top of this image — which entered polar night in 1989 and will not see sunlight again until 2107. Charon’s polar temperatures drop to near absolute zero during this long winter.

This combination of 16 one-second exposures was taken by New Horizons’ Long Range Reconnaissance Imager (LORRI) at 2:30 UT on July 17, 2015, nearly three days after closest approach to Pluto and Charon, from a range of 1.9 million miles (3.1 million kilometers).

Image Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute

Rings!

wegotrings

This is a raw image from Cassini.  The bright white specks you see are artifact that can be eliminated with processing.

This reminds me of a record album. A what? If you don’t know what that is ask your Grand Parents. :)

Image Credit: NASA/JPL-Caltech/Space Science Institute