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NASA Space Communications Moon Technology

NASA's Cassini Captures Photos of Saturn's Rings In Unprecedented Detail (voanews.com) 43

NASA's Cassini probe has captured news images of Saturn's rings in unprecedented detail. The images were captured by the probe in its penultimate mission phase of its mission that includes "20 orbits that dive past the outer edge of the main ring system" before the spacecraft plunges into the planet itself. Interestingly, the rings include what NASA calls "moonlets" embedded in them. VOA News reports: The images are the closest ever taken of Saturn's rings and, according to NASA âoeresolve details as small as 550 meters, which is on the scale of Earth's tallest buildings.â The"ring-grazing" orbits began last November and will continue until the end of April, and in addition to spotting the moonlets, they have given greater clarity to other structures within the rings such as the so-called propeller-like formations. NASA added that Cassini has also provided the "closest-ever" glimpses of two small moons, Daphnis and Pandora. The report via NASA Jet Propulsion Laboratory (JPL) adds: "Some of the structures seen in recent Cassini images have not been visible at this level of detail since the spacecraft arrived at Saturn in mid-2004. At that time, fine details like straw and propellers -- which are caused by clumping ring particles and small, embedded moonlets, respectively -- had never been seen before. (Although propellers were present in Cassini's arrival images, they were actually discovered in later analysis, the following year.) Cassini came a bit closer to the rings during its arrival at Saturn, but the quality of those arrival images (examples: 1, 2, 3) was not as high as in the new views. Those precious few observations only looked out on the backlit side of the rings, and the team chose short exposure times to minimize smearing due to Cassini's fast motion as it vaulted over the ring plane. This resulted in images that were scientifically stunning, but somewhat dark and noisy.
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NASA's Cassini Captures Photos of Saturn's Rings In Unprecedented Detail

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  • Vinyl (Score:4, Funny)

    by Anonymous Coward on Wednesday February 01, 2017 @06:57AM (#53779637)

    It kinda looks like a vinyl record. Has anyone tried playing it yet?

    • I had the same thought. Probably sounds like Lou Reed's Metal Machine Music.

    • by Tablizer ( 95088 )

      It kinda looks like a vinyl record. Has anyone tried playing it yet?

      I ran it through a digital player, and it said, "All your bases are belong to a blind trust managed by my offspring."

    • It kinda looks like a vinyl record. Has anyone tried playing it yet?

      It was an interesting idea so I actually used 287 images taken by NASA's probe to compose a virtual "vinyl imprint". I then used an optical recognition program to decode the audio and the result was great. [youtube.com]

    • It kinda looks like a vinyl record. Has anyone tried playing it yet?

      It plays: "Because of the movie, the Monolith can now be found in orbit around Jupiter."

  • Hmm (Score:5, Interesting)

    by joh ( 27088 ) on Wednesday February 01, 2017 @07:35AM (#53779695)

    I would love to see a probe going into an orbit that is synchronized to the rings. And then slowly dives into the rings, between all the small and bigger particles that make up the ring. Must be like a somewhat dense cloud of debris moving along in parallel without much motion between them.

    • I once, a long time ago in a place far far away, went to the JPL monthly lecture in Pasadena California. This one was about the Cassini probe then completing its first few months around Saturn.

      After the lecture, under the imposing model of one of the Voyager spacecraft, I met with the Project Scientist (I'm not sure if she is the same one as the current one) and asked her if they could do a "risky" maneuver at the end of Cassini's lifetime. Have Cassini go to the rings (in a synchronized fashion as you sa

      • by joh ( 27088 )

        Well, I think there is still some "action" going on in the rings. Even if everything in there would be totally synchronized with no relative motion (especially then) you would get mass clumps of particles slowly being drawn toward each other by their own mass/gravity. Basically the same thing that led to planets forming from rings of particles in the early solar system. But then this would be extremely interesting to research, because it would be the nearest thing to look at for such processes.

        It would be w

    • Pioneer 11 [wikipedia.org] was the first probe to visit Saturn. One of its trajectories considered for the mission (and eventually rejected) was to pass right through the Cassini Division [skyandtelescope.com]. Once Pioneer got there, we found out the Cassini Division wasn't quite as empty as it appears from Earth [areavoices.com].
  • by wierd_w ( 1375923 ) on Wednesday February 01, 2017 @08:40AM (#53779823)

    NASA seems to really really love using monochrome imaging systems.

    Look, I GET that this is in the outer solar system, and that the sun's light is very pitifully weak out there. I GET that. I understand that they want to gather as much light as is possible in the images.

    However, monochrome CCDs dont care what frequency the photons are. As long as they can pass through the forward optics and focus, they will add to the luminosity of the resulting image. That means that dust could be very reflective of IR, or UV light, and it would have the same whiteness. Sure, you could subtract some of that out using special optics for IR and UV, and create some horrid false-color image that does not reflect reality at all, other than artificially showing where there is UV or IR reflectivity, but visible light absorbtion/emission spectra are also very useful for scientific enquiry into such objects.

    Why does NASA not at least TRY to get true color images with extended exposure times?

    It's been a pet peeve of my for years, and I cant be the only one. I KNOW they can do it, because Voyager took lots of true color images back in the 70s. CCD tech has greatly improved since then.

    • by turkeydance ( 1266624 ) on Wednesday February 01, 2017 @08:51AM (#53779865)
      their revised unlimited plan has data caps.
    • by dargaud ( 518470 ) <slashdot2NO@SPAMgdargaud.net> on Wednesday February 01, 2017 @09:02AM (#53779903) Homepage
      Color CCDs have several disadvantages over monochrome ones for science applications: lower sensitivity, bleeding, aliasing, complexity... So normally for color pictures in space, they simply use filters of various frequencies: R, G, B for color pics, but also IR, UV and various peak frequencies of interesting chemicals (very important for science). This way it's not just a camera, but a full on science measurement. Every space camera is used like that. But why wasn't it used here ? Simply because the relative motion was too fast: they already had to use a short exposure time in order not to get a blurry shot, but changing filters take time and the pics wouldn't match in later post-processing. This method only works for subjects that don't move (or if you don't move yourself).
      • A method similar to what is done for digital HDR recording would fix this problem, but would admittedly add tremendously to the vehicle weight.

        EG, you have a single forward optic, but introduce several beam splitters, which then go to individual monochrome CCDs behind the various filters. (use a clear saphire prism beam splitter to get nIR and UV on the same source optic) You then assign each CCD a channel, and develop the image accordingly.

        • Yes and adding tremendously to the vehicle weight (and complexity and cost) is exactly what drives rocket scientists to vote Democratic. These probes are all about compromise. I'm sure this argument is played out in a bunch of archived memos somewhere.

          The fact that this thing has been operating since 1997 and pushing the boundaries of planetary science says they made most of the right decisions.

    • Color cameras are just crippled cameras. Each pixel in the image is made from 4 pixels in the camera. One red, one blue and 2 green. The camera then balances the output to make the output pixel. With a monochrome camera, each pixel provides separate output. That way data is collected 4 times faster. When astronomers, both professional and amateur, create those wonderful color pictures of deep sky objects, they do it with filters and a monochrome camera. They will take many pictures to collect hours of black
    • by Anonymous Coward

      I KNOW they can do it, because Voyager took lots of true color images back in the 70s. CCD tech has greatly improved since then.

      No, you remember very wrong. Voyager didn't use CCD visible light cameras, but vidicon tubes like old TV cameras. Also, both the Narrow Angle Camera [nasa.gov] and Wide Angle Camera [nasa.gov] used a filter wheel with 8 different filters.

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