Category Archives: Cassini

Mimas

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We need more missions like Cassini going to other as yet unexplored planets. Have a look at our Mimas page

The original caption:

Shadows cast across Mimas’ defining feature, Herschel Crater, provide an indication of the size of the crater’s towering walls and central peak.

Named after the icy moon’s discoverer, astronomer William Herschel, the crater stretches 86 miles (139 kilometers) wide — almost one-third of the diameter of Mimas (246 miles or 396 kilometers) itself.

Large impact craters often have peaks in their center — see Tethys’ large crater Odysseus in PIA08400. Herschel’s peak stands nearly as tall as Mount Everest on Earth.

This view looks toward the anti-Saturn hemisphere of Mimas. North on Mimas is up and rotated 21 degrees to the left. The image was taken with the Cassini spacecraft narrow-angle camera on Oct. 22, 2016 using a combination of spectral filters which preferentially admits wavelengths of ultraviolet light centered at 338 nanometers.

The view was acquired at a distance of approximately 115,000 miles (185,000 kilometers) from Mimas and at a Sun-Mimas-spacecraft, or phase, angle of 20 degrees. Image scale is 3,300 feet (1 kilometer) per pixel.

Credit: NASA/JPL-Caltech/Space Science Institute

Sunny Saturn

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The sunny northern hemisphere on Saturn.

NASA:
Sunlight truly has come to Saturn’s north pole. The whole northern region is bathed in sunlight in this view from late 2016, feeble though the light may be at Saturn’s distant domain in the solar system.

The hexagon-shaped jet-stream is fully illuminated here. In this image, the planet appears darker in regions where the cloud deck is lower, such the region interior to the hexagon. Mission experts on Saturn’s atmosphere are taking advantage of the season and Cassini’s favorable viewing geometry to study this and other weather patterns as Saturn’s northern hemisphere approaches Summer solstice.

This view looks toward the sunlit side of the rings from about 51 degrees above the ring plane. The image was taken with the Cassini spacecraft wide-angle camera on Sept. 9, 2016 using a spectral filter which preferentially admits wavelengths of near-infrared light centered at 728 nanometers.

The view was obtained at a distance of approximately 750,000 miles (1.2 million kilometers) from Saturn. Image scale is 46 miles (74 kilometers) per pixel.

Credit: NASA/JPL-Caltech/Space Science Institute

Pandora

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This is the Saturn moon Pandora like we’ve never seen before and likely not to see again for a long-long time once the Cassini mission comes to an end.

The details from the Cassini mission team:
This image from NASA’s Cassini spacecraft is one of the highest-resolution views ever taken of Saturn’s moon Pandora. Pandora (52 miles, 84 kilometers) across orbits Saturn just outside the narrow F ring.

The spacecraft captured the image during its closest-ever flyby of Pandora on Dec. 18, 2016, during the third of its grazing passes by the outer edges of Saturn’s main rings. (For Cassini’s closest view prior to this flyby, see PIA07632, which is also in color.)

The image was taken in green light with the Cassini spacecraft narrow-angle camera at a distance of approximately 25,200 miles (40,500 kilometers) from Pandora, or phase, angle of 29 degrees. Image scale is 787 feet (240 meters) per pixel.

Image: NASA/JPL-Caltech/Space Science Institute

Mimas

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NASA’s caption:
It may look as though Saturn’s moon Mimas is crashing through the rings in this image taken by NASA’s Cassini spacecraft, but Mimas is actually 28,000 miles (45,000 kilometers) away from the rings. There is a strong connection between the icy moon and Saturn’s rings, though. Gravity links them together and shapes the way they both move.

The gravitational pull of Mimas (246 miles or 396 kilometers across) creates waves in Saturn’s rings that are visible in some Cassini images. Mimas’ gravity also helps create the Cassini Division (not pictured here), which separates the A and B rings.

This view looks toward the anti-Saturn hemisphere of Mimas. North on Mimas is up and rotated 15 degrees to the right. The image was taken in green light with the Cassini spacecraft narrow-angle camera on Oct. 23, 2016.

The view was acquired at a distance of approximately 114,000 miles (183,000 kilometers) from Mimas and at a Sun-Mimas-spacecraft, or phase, angle of 29 degrees. Image scale is 3,300 feet (1 kilometer) per pixel.

Image: NASA/JPL-Caltech/Space Science Institute

New Views of Cassini

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If all goes as planned this is just the first of a new set of images the Cassini spacecraft will be returning in the new phase of its mission.

Click the image for a larger version.

From NASA:
This view from NASA’s Cassini spacecraft was obtained about half a day before its first close pass by the outer edges of Saturn’s main rings during its penultimate mission phase.

The view shows part of the giant, hexagon-shaped jet stream around the planet’s north pole. Each side of the hexagon is about as wide as Earth. A circular storm lies at the center, at the pole (see PIA14944).

The image was taken with the Cassini spacecraft wide-angle camera on Dec. 3, 2016, at a distance of about 240,000 miles (390,000 kilometers) from Saturn. Image scale is 14 miles (23 kilometers) per pixel.

Credit: NASA/JPL-Caltech/Space Science Institute

Mimas and Saturn

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Be sure to check out our page on Mimas.

 

Saturn’s icy moon Mimas is dwarfed by the planet’s enormous rings.

Because Mimas (near lower left) appears tiny by comparison, it might seem that the rings would be far more massive, but this is not the case. Scientists think the rings are no more than a few times as massive as Mimas, or perhaps just a fraction of Mimas’ mass. Cassini is expected to determine the mass of Saturn’s rings to within just a few hundredths of Mimas’ mass as the mission winds down by tracking radio signals from the spacecraft as it flies close to the rings.

The rings, which are made of small, icy particles spread over a vast area, are extremely thin — generally no thicker than the height of a house. Thus, despite their giant proportions, the rings contain a surprisingly small amount of material.

Mimas is 246 miles (396 kilometers) wide.

This view looks toward the sunlit side of the rings from about 6 degrees above the ring plane. The image was taken in red light with the Cassini spacecraft wide-angle camera on July 21, 2016.

The view was obtained at a distance of approximately 564,000 miles (907,000 kilometers) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 31 degrees. Image scale is 34 miles (54 kilometers) per pixel.

Image and caption: NASA/JPL-Caltech/Space Science Institute

Prometheus

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Nice look at Prometheus from Cassini.

From Cassini/NASA:
Surface features are visible on Saturn’s moon Prometheus in this view from NASA’s Cassini spacecraft. Most of Cassini’s images of Prometheus are too distant to resolve individual craters, making views like this a rare treat.

Saturn’s narrow F ring, which makes a diagonal line beginning at top center, appears bright and bold in some Cassini views, but not here. Since the sun is nearly behind Cassini in this image, most of the light hitting the F ring is being scattered away from the camera, making it appear dim. Light-scattering behavior like this is typical of rings comprised of small particles, such as the F ring.

This view looks toward the unilluminated side of the rings from about 14 degrees below the ring plane. The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Sept. 24, 2016..

The view was acquired at a distance of approximately 226,000 miles (364,000 kilometers) from Prometheus and at a sun-Prometheus-spacecraft, or phase, angle of 51 degrees. Image scale is 1.2 miles (2 kilometers) per pixel.

Image: NASA/JPL-Caltech/Space Science Institute

Rings in Detail

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A great look at the rings of Saturn from the Cassini spacecraft. Saturn is a treasure, I don’t think I have ever looked at it through even a small telescope and not thought “WOW”.

Check out Saturn.

From NASA and Cassini:
This view from NASA’s Cassini spacecraft showcases some of the amazingly detailed structure of Saturn’s rings.

The rings are made up of many smaller ringlets that blur together when seen from a distance. But when imaged up close, the rings’ structures display quite a bit of variation. Ring scientists are debating the nature of these features — whether they have always appeared this way or if their appearance has evolved over time.

This view looks toward the sunlit side of the rings from about 4 degrees above the ring plane. The image was taken in visible light with the Cassini spacecraft wide-angle camera on Sept. 24, 2016.

The view was acquired at a distance of approximately 283,000 miles (456,000 kilometers) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 32 degrees. Image scale is 17 miles (27 kilometers) per pixel.

Credit: NASA/JPL-Caltech/Space Science Institute