APOD: Saturn from Above (2016 Sep 25)

Comments and questions about the APOD on the main view screen.
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APOD Robot
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APOD: Saturn from Above (2016 Sep 25)

Post by APOD Robot » Sun Sep 25, 2016 4:14 am

Image Saturn from Above

Explanation: This image of Saturn could not have been taken from Earth. No Earth based picture could possibly view the night side of Saturn and the corresponding shadow cast across Saturn's rings. Since Earth is much closer to the Sun than Saturn, only the day side of the ringed planet is visible from the Earth. In fact, this image mosaic was taken earlier this year by the robotic Cassini spacecraft now orbiting Saturn, just before filming a 44-hour video of Saturn rotating. The beautiful rings of Saturn are seen in full expanse, while cloud details are visible including the polar hexagon surrounding the north pole. The Cassini mission is now in its final year as the spacecraft is scheduled to be programmed to dive into Saturn's atmosphere next September.

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Boomer12k
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Re: APOD: Saturn from Above (2016 Sep 25)

Post by Boomer12k » Sun Sep 25, 2016 5:47 am

Wonderful shot... Wish I was there....

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heehaw

Re: APOD: Saturn from Above (2016 Sep 25)

Post by heehaw » Sun Sep 25, 2016 2:32 pm

Found this: "Saturn's rings are incredibly thin. The main rings are generally only about 30 feet (10 meters) thick, though parts of the main and other rings can be several kilometers thick. The rings are made of dusty ice, in the form of boulder-sized and smaller chunks that gently collide with each other as they orbit around Saturn." How I wish Cassini could get a close-up of part of a ring!

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Re: APOD: Saturn from Above (2016 Sep 25)

Post by danhammang » Sun Sep 25, 2016 5:00 pm

I'm always amazed when I look at these Cassini generated images of Saturn. The planet looks so different than ours or any of the others in our solar system. Even Jupiter, Saturn's gas planet cousin, doesn't seem as otherly. It's so ethereal, at least from an imaging standpoint. I imagine the physical reality would be another story. It will be interesting to see what the last data messages from Cassini tell us as it plunges in next year.

Tekija

Re: APOD: Saturn from Above (2016 Sep 25)

Post by Tekija » Sun Sep 25, 2016 6:03 pm

Fantastic image! And it has the Asimov colors.

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Re: APOD: Saturn from Above (2016 Sep 25)

Post by Evenstar » Sun Sep 25, 2016 6:52 pm

I wonder if the sort-of-bluish-looking very center of the 'north' pole of Saturn is a break in the cloud structure one robotic Cassini spacecraft might be able to peer through...or better yet descend through when it de-orbits?
Last edited by Evenstar on Mon Sep 26, 2016 7:28 am, edited 1 time in total.
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FLPhotoCatcher
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Re: APOD: Saturn from Above (2016 Sep 25)

Post by FLPhotoCatcher » Mon Sep 26, 2016 1:39 am

I wonder how much material the rings contain... If they were rolled into a solid ball, how big would it be?

SeedsofEarth

Re: APOD: Saturn from Above (2016 Sep 25)

Post by SeedsofEarth » Mon Sep 26, 2016 2:09 am

I just finished watching the 44 hr. rotation of Saturn video, and I have a question: How was Cassini able to stay in one position as the planet rotated for 44 hours? Even if it had been in a Saturn-synchronous orbit, it still would have followed a stationary point on the planet as it rotated. In the video, it seems to be holding its position relative to the rotating planet? How was this possible?

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Re: APOD: Saturn from Above (2016 Sep 25)

Post by geckzilla » Mon Sep 26, 2016 2:16 am

SeedsofEarth wrote:I just finished watching the 44 hr. rotation of Saturn video, and I have a question: How was Cassini able to stay in one position as the planet rotated for 44 hours? Even if it had been in a Saturn-synchronous orbit, it still would have followed a stationary point on the planet as it rotated. In the video, it seems to be holding its position relative to the rotating planet? How was this possible?
It wasn't stationary. Per the description:
When it began taking images for this movie sequence, Cassini was 1,847,000 miles (2,973,000 kilometers) from Saturn, with an image scale of 355 kilometers per pixel. When it finished gathering the images, the spacecraft had moved 171,000 miles (275,000 kilometers) closer to the planet, with an image scale of 200 miles (322 kilometers) per pixel.
It was almost 3 million km from the planet, so it was moving relatively slowly and only covered 9.25% of the distance between itself and the planet over the 44 hour period. I'd say it was moving about 6250 km per hour, but it was also accelerating constantly as it approached.
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Chris Peterson
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Re: APOD: Saturn from Above (2016 Sep 25)

Post by Chris Peterson » Mon Sep 26, 2016 5:22 am

FLPhotoCatcher wrote:I wonder how much material the rings contain... If they were rolled into a solid ball, how big would it be?
Like a small ice moon, perhaps 500 km in diameter.
Chris

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Re: APOD: Saturn from Above (2016 Sep 25)

Post by DavidLeodis » Mon Sep 26, 2016 12:28 pm

It's said that beauty is in the eye of the beholder and so I find it to be a beautiful and wonderful image. :)

I'm glad the 44 hour video was compressed into 40 seconds as I would never have managed to stay awake otherwise! :wink: