Astronomy Picture of the Week – Puzzled Iapetus

Yet another one from Cassini’s Grand Finale. Yup, it’s still going…

Iapetus is a world of contrast, with light and dark regions fitting together like cosmic puzzle pieces.

Cassini Regio on Iapetus (914 miles or 1,471 kilometers across) is covered in a layer of dark, dusty material creating a stark contrast to the much brighter region that surrounds it. This leads to the moon’s distinctive, two-toned appearance. To learn more about the cause of the contrast between regions, see Encountering Iapetus.

This view looks toward Saturn-facing hemisphere of Iapetus. North on Iapetus is up and rotated 20 degrees to the right. The image was taken in visible light with the Cassini spacecraft narrow-angle camera on March 11, 2017.

The view was obtained at a distance of approximately 1.6 million miles (2.6 million kilometers) from Iapetus. Image scale is 9 miles (15 kilometers) per pixel.

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Astronomy Picture of the Week: Mimas Dwarfed

We continue with images from Cassini’s Grand Finale. This time, it’s an image from over Saturn’s north pole, with a teeny tiny dot, Mimas, in the upper right…

From high above Saturn’s northern hemisphere, NASA’s Cassini spacecraft gazes over the planet’s north pole, with its intriguing hexagon and bullseye-like central vortex.

Saturn’s moon Mimas is visible as a mere speck near upper right. At 246 miles (396 kilometers across) across, Mimas is considered a medium-sized moon. It is large enough for its own gravity to have made it round, but isn’t one of the really large moons in our solar system, like Titan. Even enormous Titan is tiny beside the mighty gas giant Saturn.

This view looks toward Saturn from the sunlit side of the rings, from about 27 degrees above the ring plane. The image was taken in green light with the Cassini spacecraft wide-angle camera on March 27, 2017.

The view was acquired at a distance of approximately 617,000 miles (993,000 kilometers) from Saturn. Image scale is 37 miles (59 kilometers) per pixel. Mimas’ brightness has been enhanced by a factor of 3 in this image to make it easier to see.

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Astronomy Picture of the Week: The Keeler Gap

Another one from Cassini’s Grand Finale mission…

Here’s the text from the photo page; the image is below the fold (and, as usual, you can click on it for the tiff download)…

Before Cassini entered its Grand Finale orbits, it acquired unprecedented views of the outer edges of the main ring system. For example, this close-up view of the Keeler Gap, which is near the outer edge of Saturn’s main rings, shows in great detail just how much the moon Daphnis affects the edges of the gap.

This image was part of a mosaic that included Daphnis (The Realm of Daphnis).

Daphnis creates waves in the edges of the gap through its gravitational influence. Some clumping of ring particles can be seen in the perturbed edge, similar to what was seen on the edges of the Encke Gap back when Cassini arrived at Saturn in 2004.

This view looks toward the sunlit side of the rings from about 3 degrees above the ring plane. The view was acquired at a distance of approximately 18,000 miles (30,000 kilometers) from Daphnis and at a Sun-Daphnis-spacecraft, or phase, angle of 69 degrees. Image scale is 581 feet (177 meters) per pixel. The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Jan. 16, 2017.

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Self Care – Astronomy Picture of the Week: Propeller Belts of Saturn

I’m still pulling from Cassini’s Grand Finale mission. Is it at all strange that I’m so sad about this? I don’t want to say I feel like I’ve built some kind of bond or something with Cassini. It’s just that Saturn’s always been my favorite planet, and for as long as I’ve been interested, Cassini’s been our window to it.

And now, Cassini’s incredible life is coming to an end. And I’m sad about that.

But anyways…

Cassini shot this amazing, extremely sharp image of some features in Saturn’s A ring called propeller belts. As always, click on the image for the tiff download…

Also, I’m putting this one below the fold…

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Self Care – Astronomy [Video] of the Week: Cassini’s Grand Finale

This, to be honest, is really sad for me.

Saturn has always been my favorite planet, so Cassini holds a very special place in my heart. I love Cassini. I follow it on Twitter, and follow updates very closely. Cassini has been in space for 20 years, and at Saturn 13 years. It’s been an amazing run, with so many incredible findings about Saturn and it’s wondrous and fascinating moons.

But time is running out. Cassini is running out of fuel. So NASA has planned a Grand Finale. An epic, bittersweet grand finale.

First, Cassini will dive between Saturn and it’s rings. It’s already done that once, on April 26. And it’s geared up to do it 21 more times.

Then, on September 15, Cassini will… um…

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