Tons of fun with a latest Ceres picture releases from Dawn

May 23, 2015 - photo frame


Headshot of Emily Lakdawalla

Posted by Emily Lakdawalla

22-05-2015 16:59 CDT

Topics:

flattering pictures,

pledge design processing,

asteroids,

Dawn,

asteroid 1 Ceres

Fantastic new images of Ceres continue to brief out of a Dawn mission, and armchair scientists all over a universe are zooming into them, exploring them, and perplexing to solve a puzzles that they contain. It’s extensive fun to have a event to see a new universe for a initial time, learn bizarre features, and try to explain them. we do see a lot of pledge scientists creation some mistakes when perplexing to appreciate a images, and suspicion we would spend a blog post explaining them, and afterwards prominence some of a cold things that members of a open are doing with a photos.

Let’s start by looking during this positively illusory animation of a spinning Ceres, that contains 51 singular images and covers somewhat some-more than one rotation.

Dawn's Ceres Rotation Characterization 3 (uncorrected)

NASA / JPL / UCLA / MPS / DLR / IDA

Dawn’s Ceres Rotation Characterization 3 (uncorrected)

This animation consists of 51 frames shot by Dawn during a Rotation Characterization 3 on May 4, 2015. Dark specks that burst around in a design are artifacts.

The initial thing many people notice is that a puzzling white spots are violation adult into some-more white spots than we saw previously, though they’re no reduction puzzling than before. we have review members of a scholarship group advise possibly unprotected ice or salts as a possibility. The second thing people notice is puzzling black dots jumping around a image. I’ve had people ask me if these were mini-moons of Ceres, or maybe caves on Ceres, and I’d not be astounded if there were some denizens of a Internet interpreting them to be ships of a Air Force of a Cerean Ice Weasels.

But if we demeanour closely, you’ll see that a lot of a black spots have a same figure from design to image, nonetheless they’re in opposite places on Ceres. Moreover, when there’s some-more than one black dot in an image, they tend to be in a same position with honour to any other. That’s no moon; that’s schmutz in a camera. One of my supporters on Twitter finished a video to denote a determined relations positions of a 3 many apparent schmutz bits, that is helpful, though we wanted to purify them off a images entirely. So we took a frames from a animation and aligned them on a schmutz bits, afterwards built them, averaging together a values of all a pixels during any spot. This routine suggested 8 or 9 schmutz spots that spot all of a Dawn images, circled in yellow on a design below.

Schmutz in Dawn's framing camera

NASA / JPL / UCLA / MPS / DLR / IDA / Emily Lakdawalla

Schmutz in Dawn’s framing camera

Stacking all a images from a May 4, 2015 Rotation Characterization 3 animation reveals 9 spots that are anomalously dim in all images in that they tumble atop Ceres. Because their edges are frail they expected paint something on a detector rather than in a optics (where they’d be out of focus).

In Photoshop, we took my schmutz map into a animation and used it to brand where all of a offending spots were on any of a 51 frames, and erased them regulating possibly a recovering brush or a counterpart stamp. In doing so, I’ve crossed a line from “analysis” to “art”. These images are no longer suitable for science, that is since scholarship teams generally do not do this kind of cut dismissal on their images before posting them. There is no worse thing for a scientist to do than to make data! But now a rest of us can suffer a animation though a distractions of dim spots, and people won’t email me about caves and moons on Ceres. Or ice weasels. we have also slowed down a animation a little, and we private a few of a frames so that a initial and final support compare some-more closely.

Ceres' full rotation, Dawn Rotation Characterization 3, May 4, 2015

NASA / JPL / UCLA / MPS / DLR / IDA / Emily Lakdawalla

Ceres’ full rotation, Dawn Rotation Characterization 3, May 4, 2015

This animation consists of 44 photos of Ceres taken over one finish Ceres day on May 4, 2015. Dawn was in a frigid orbit, relocating from north to south, so a ends of a animation don’t utterly compare up. Dust specks have been spotless from a images by portrayal over influenced pixels. The strange animation (which had 51 graphic frames, covering somewhat some-more than one rotation) is accessible here.

Here’s an swap chronicle of a corrected images. It is so overwhelming that they have common so many images with us. You can check out engaging facilities and see how they seem to change as Ceres’ revolution carries them in and out of view.

51 views of Ceres, Dawn Rotation Characterization 3, May 4, 2015

NASA / JPL / UCLA / MPS / DLR / IDA / Emily Lakdawalla

51 views of Ceres, Dawn Rotation Characterization 3, May 4, 2015

Dawn took these images of Ceres over somewhat some-more than one finish Ceres day on May 4, 2015. Dust specks have been spotless from a images by portrayal over influenced pixels. The strange animation is accessible here.

Dawn is now spiraling downward further, and has prisoner several images for visual navigation in that Ceres is so vast that it some-more than fills a margin of view. Here is a best print nonetheless of those puzzling splendid spots — and a new event for memebrs of a open to misrepresent images. I’ll uncover we a photo, afterwards explain.

Dawn perspective of Ceres on May 16, 2015

NASA / JPL / UCLA / MPS / DLR / IDA

Dawn perspective of Ceres on May 16, 2015

Dawn prisoner this print of Ceres from a widen of 7200 kilometers as it was spiraling down from a former Rotation Characterization 3 altitude to Survey Orbit.

I have seen many people stand out a void with a white spots, increase it several times, and widen a contrariety to try to see some-more fact (see, for instance, here and here and here). Unfortunately, there is no some-more fact to be seen. The white spots are jam-packed — as white as white can be — and all a encouragement that everybody is doing to them is usually bringing out JPEG application artifacts. To explain: JPEG is an design format that compresses design information by converting lists of pixel values into many shorter lists of equations and coefficients (if we ever complicated Fourier transforms in math or physics, it’s a identical process). It’s rarely effective during timorous print record sizes, though when your mechanism turns a lists of equations behind into a photo, it’s not utterly a same as a print we started with; it’s usually an approximation. This is called lossy compression. The smaller a record distance we restrict a design to, a some-more of an estimation it is, and a some-more of a strange information is lost. In rarely dense images, we can see artifacts of a JPEG application intrigue as a checkerboardy hardness and as bright-dark-bright-dark pixel patterns wherever there was a pointy range in a strange image.

The visual navigation print that we enclosed above was dense so many before recover that those dim schmutz spots we was articulate about progressing in this post have been roughly totally erased by application artifacts. (I inquired with a goal either a application was finished on a booster or after attainment on Earth, and we was told it was finished on Earth, so we have improved versions of these images to demeanour brazen to once a scholarship group rigourously releases a data.) In a way, a schmutz spots are indeed useful here since they denote usually how many fact was mislaid with a JPEG compression. In a comparison below, a tip quarrel of images is from my schmutz map; a bottom quarrel is from a Op Nav photo. In a bottom quarrel we can see a 8-by-8-pixel checkerboard that is a revealing pointer of JPEG compression, and one of a schmutz spots has roughly totally disappeared.

Dawn schmutz comparison before and after JPEG compression

The reason I’m going on and on about a JPEG application is to make a indicate that it is a rubbish of time to try to increase a design of a white spots to exhibit some-more detail. The usually excellent sum accessible in this design are mostly not real. They have all to do with application artifacts and scarcely zero to do with geology. In fact, I’d suggest shrinking a visual navigation design before perplexing to investigate it, or maybe blurring it, as a process of deemphasizing a forged facilities introduced by a record compression. The animation during a tip of this post doesn’t have a same problem; it was not posted as a JPEG though rather as a GIF. For black-and-white photos, it’s probable for GIF to be a lossless application scheme, and a peculiarity of those images is many higher.

I could write a integrate thousand difference on interpretation of these photos, though we won’t; there is adequate fact in these photos and we have adequate systematic training that for me to do too many essay about them would seem to be stepping on a toes of a scholarship team. we will wait until they emanate press releases, tell in Science, or benefaction during a scholarship meeting, and afterwards we will critique their interpretations! What we will do is share some of a cold research that other denizens of a Internet have been doing with a pictures.

First adult is this poetic updated tellurian map of Ceres, that uses all of a many new pictures, including and adult to a publicly expelled ones from op Nav 8. (It came from this contention on unmannedspaceflight.com, where we might find a some-more present chronicle of a map if we are reading this post many after we wrote it.)

Global map of Ceres as of May 16, 2015

NASA / JPL / UCLA / MPS / DLR / IDA / Steve Albers

Global map of Ceres as of May 16, 2015

Grab your red-blue eyeglasses to suffer this unequivocally cold 3D perspective of a rotating Ceres, courtesy of Nathan Frey (“walfy”) during unmannedspaceflight.com.

Probably a coolest thing I’ve seen is this animation, by user ZLD during unmannedspaceflight.com, of an removed streaky rise in Ceres’ southern hemisphere. The same user also finished an animation of a white spots.

One object that we beheld that we can’t assistance mentioning is: demeanour during a core of this image and notice what a strikingly ideally hexagon-shaped void lies there.

I’ll tighten with a poetic crescent perspective of Ceres, one of 3 that a goal expelled final week. we adore crescent views of worlds of a solar system, since a thinner a crescent, a some-more comparison they all look. The craters are a small deeper and central-peakier than you’d see on Dione or Tethys, and a creation a bit lumpier than you’d see on Mercury or a Moon. But they all kind of demeanour comparison from this angle.

Crescent Ceres, Apr 30, 2015

NASA / JPL / UCLA / MPS / DLR / IDA

Crescent Ceres, Apr 30, 2015

Dawn prisoner this crescent perspective of Ceres while in a initial frigid mapping orbit.

See other posts from May 2015


Other associated posts:


New Horizons during Pluto


Rim of Home Plate, Spirit luminary 1886


Equatorial perspective of comet Churyumov-Gerasimenko

Or review some-more blog entries about:

flattering pictures,

pledge design processing,

asteroids,

Dawn,

asteroid 1 Ceres

Comments:

Gregk: 05/22/2015 09:29 CDT

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