APOD: A Landslide on Asteroid Vesta (2011 Nov 28)

Comments and questions about the APOD on the main view screen.
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Re: APOD: A Landslide on Asteroid Vesta (2011 Nov 28)

Post by JohnD » Thu Dec 01, 2011 10:50 pm

Thank you, Chris!

JPL seems to have it right, calling this a scarp, while NASA are over the top (as it were) by using 'cliff'.

John

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Re: APOD: A Landslide on Asteroid Vesta (2011 Nov 28)

Post by neufer » Sat Dec 03, 2011 6:51 pm

Click to play embedded YouTube video.
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Re: APOD: A Landslide on Asteroid Vesta (2011 Nov 28)

Post by Flase » Wed Dec 07, 2011 10:55 pm

I have a question. Are Dawn's photos black'n'white :?: ? I have been trying to use photoshop to increase the saturation in some pictures and I haven't found even subtle hints of colour. Even the moon has more colour in it.

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Re: APOD: A Landslide on Asteroid Vesta (2011 Nov 28)

Post by neufer » Thu Dec 08, 2011 2:20 am

Flase wrote:
I have a question. Are Dawn's photos black'n'white :?: ? I have been trying to use photoshop to increase the saturation in some pictures and I haven't found even subtle hints of colour. Even the moon has more colour in it.
http://www.universetoday.com/90374/rainbow-of-colors-reveal-asteroid-vesta-as-more-like-a-planet/#more-90374 wrote:
Rainbow of Colors Reveal Asteroid Vesta as More Like a Planet
by Ken Kremer on December 7, 2011 <<The giant Asteroid Vesta is among the most colorful bodies in our entire solar system and it appears to be much more like a terrestrial planet than a mere asteroid, say scientists deciphering stunning new images and measurements of Vesta received from NASA’s revolutionary Dawn spacecraft. The space probe only recently began circling about the huge asteroid in July after a four year interplanetary journey.

Vesta is a heavily battered and rugged world that’s littered with craters and mysterious grooves and troughs. It is the second most massive object in the Asteroid Belt and formed at nearly the same time as the Solar System some 4.5 Billion years ago.

“The framing cameras show Vesta is one of the most colorful objects in the solar system,” said mission scientist Vishnu Reddy of the Max Planck Institute for Solar System Research in Katlenburg-Lindau, Germany. “Vesta is unlike any other asteroid we have visited so far.”

Scientists presented the new images and findings from Dawn at the American Geophysical Union meeting this week in San Francisco.

“Vesta is a transitional body between a small asteroid and a planet and is unique in many ways,” Reddy said. “We do not know why Vesta is so special.” Although many asteroids look like potatoes, Reddy said Vesta reminds him more of an avocado.

Asteroid Vesta is revealed as a ‘rainbow-colored palette’ in a new image mosaic (above) showcasing this alien world of highly diverse rock and mineral types of many well-separated layers and ingredients. Researchers assigned different colors as markers to represent different rock compositions in the stunning new mosaic of the asteroid’s southern hemisphere. The green areas in the mosaic suggest the presence of the iron-rich mineral pyroxene or large-sized particles, according to Eleonora Ammannito, from the Visible and Infrared (VIR) spectrometer team of the Italian Space Agency. The ragged surface materials are a mixture of rapidly cooled surface rocks and a deeper layer that cooled more slowly. “The surface is very much consistent with the variability in the HED (Howardite-Eucritic-Diogenite) meteorites,” Prof. Chris Russell, Dawn Principal Investigator (UCLA) told Universe Today in an exclusive interview. “There is Diogenite in varying amounts.” “The different colors represent in part different ratios of Diogenite to Eucritic material. Other color variation may be due to particle sizes and to aging,” Russell told me.

No evidence of volcanic materials has been detected so far, said David Williams, Dawn participating scientist of Arizona State University, Tucson. Before Dawn arrived, researchers expected to observe indications of volcanic activity. So, the lack of findings of volcanism is somewhat surprising. Williams said that past volcanic activity may be masked due to the extensive battering and resultant mixing of the surface regolith.

“More than 10,000 high resolution images of Vesta have been snapped to date by the framing cameras on Dawn,” Dr. Marc Rayman told Universe Today. Rayman is Dawn’s Chief Engineer from NASA’s Jet Propulsion Lab (JPL) in Pasadena, Calif.

Dawn will spend a year in orbit at Vesta and investigate the asteroid at different altitudes with three on-board science instruments from the US, Germany and Italy. The probe will soon finish spiraling down to her lowest mapping orbit known as LAMO (Low Altitude Mapping Orbit), approximately 210 kilometers above Vesta’s surface. “Dawn remains on course to begin its scientific observations in LAMO on December 12,” said Rayman.>>
Last edited by neufer on Thu Dec 08, 2011 3:25 am, edited 1 time in total.
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Re: APOD: A Landslide on Asteroid Vesta (2011 Nov 28)

Post by Flase » Thu Dec 08, 2011 2:51 am

Thanks but I'm still confused. The example in the article has only black and white and false colour. It also seems to imply that filters are only used as scientific instruments and not to create true-colour images. Certainly when I test the hex value of colours in a Vesta image, they are all mathematically precisely grey, although the image isn't grey-scale. Are any of Dawn's photos in true colour?

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Re: APOD: A Landslide on Asteroid Vesta (2011 Nov 28)

Post by neufer » Thu Dec 08, 2011 3:20 am

Flase wrote:
Thanks but I'm still confused. The example in the article has only black and white and false colour. It also seems to imply that filters are only used as scientific instruments and not to create true-colour images. Certainly when I test the hex value of colours in a Vesta image, they are all mathematically precisely grey, although the image isn't grey-scale. Are any of Dawn's photos in true colour?
[c]It's not all that attractive:[/c]
http://dawn.jpl.nasa.gov/multimedia/imageoftheday/image.asp?date=20111026 wrote: <<This composite image is a simulated true color image of Vesta’s northern and equatorial regions. It was produced by combining images obtained by the Visible and Infrared Imaging Spectrometer (VIR) instrument aboard NASA’s Dawn spacecraft. The VIR instrument can image Vesta in many different wavelength regions, called bands, in the near ultraviolet, visible and infrared parts of the electromagnetic spectrum, which corresponds to a wavelength range of 300nm to 5000nm. This is an RGB composite image where red is set as the 700nm band, green is set as the 550nm band and blue is set as the 440nm band. The wavelength of red light is around 700nm, of green light is around 550nm and of blue light is around 440nm, so this image approximates what the human eye would see looking at Vesta. It is an approximation because the human eye can see many more wavelengths than the three used here. This image shows the diverse colors of Vesta’s surface: the left and middle parts of the image are dominated by reddish hues and the right part of the image is more blue in color.

NASA’s Dawn spacecraft obtained the images used to make this composite image with its Visible and Infrared Imaging Spectrometer on July 23rd 2011. The distance to the surface of Vesta is 5200km and the average image resolution is 1.5 kilometers per pixel.>>
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Re: APOD: A Landslide on Asteroid Vesta (2011 Nov 28)

Post by Chris Peterson » Thu Dec 08, 2011 3:32 am

Flase wrote:Thanks but I'm still confused. The example in the article has only black and white and false colour. It also seems to imply that filters are only used as scientific instruments and not to create true-colour images. Certainly when I test the hex value of colours in a Vesta image, they are all mathematically precisely grey, although the image isn't grey-scale. Are any of Dawn's photos in true colour?
No. Dawn cannot take color images- it can only take wideband or narrowband images, and none of the narrowband filters overlap. The spacecraft moves much too quickly with respect to its target to frame multiple filtered shots.

F Center Bandwidth
1 450 ±10 to 920 ±10
2 430 ±2 40 ± 5
3 550 ±2 40 ± 5
4 650 ±2 40 ± 5
5 750 ±2 40 ± 5
6 830 ±2 40 ± 5
7 920 ±2 40 ± 5
8 980 ±2 80 ± 5

However, as the image database grows, it is possible to map physical locations on Vesta to data collected through different filters, and also to data collected by the imaging spectrometer, and recreate images that approximate "true color". But all raw and minimally processed images made with the Framing Camera will be B&W. Images from the spectrometer may be color, but will typically be false color, with the intent of showing composition.
Chris

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Re: APOD: A Landslide on Asteroid Vesta (2011 Nov 28)

Post by Flase » Thu Dec 08, 2011 3:53 am

Poo. A $150 digital camera from Dick Smith can take pictures in colour. Couldn't they just gaffertape one of them on? Also, one of these articles mentions that the framing camera has only a million pixels. A cheap digital camera nowadays can do 8 megapixels. Surely you just need a USB port on the probe and you can upload better results. No?

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Re: APOD: A Landslide on Asteroid Vesta (2011 Nov 28)

Post by neufer » Thu Dec 08, 2011 4:27 am

Flase wrote:
A $150 digital camera from Dick Smith can take pictures in colour.
Couldn't they just gaffertape one of them on?
Let's just gaffer-tape Dick Smith on and he could describe the colors to us.
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Re: APOD: A Landslide on Asteroid Vesta (2011 Nov 28)

Post by Flase » Thu Dec 08, 2011 7:14 am

No no no, I'm afraid that would be inefficient and inaccurate. He would also die and it might be messy.

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Re: APOD: A Landslide on Asteroid Vesta (2011 Nov 28)

Post by Chris Peterson » Thu Dec 08, 2011 7:20 am

Flase wrote:Poo. A $150 digital camera from Dick Smith can take pictures in colour. Couldn't they just gaffertape one of them on? Also, one of these articles mentions that the framing camera has only a million pixels. A cheap digital camera nowadays can do 8 megapixels. Surely you just need a USB port on the probe and you can upload better results. No?
By the time you space qualify a color CCD camera, you're looking at millions of dollars. And it isn't much good for science, but consumes very limited weight and power allocations- meaning if you include the color camera, something of real scientific value needs to go.
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Re: APOD: A Landslide on Asteroid Vesta (2011 Nov 28)

Post by Flase » Thu Dec 08, 2011 7:43 am

Well it's a shame. Most of the pictures of Mars that you get are recreated from computer models and just don't look right. They look like a computer game or something. Vesta and Ceres will look the same, like a piece of CGI plastic. At least with them, you won't need to model an atmosphere with clouds.

Is it really of no scientific value to have pictures that look accurate to the human eye? I reckon it is of scientific value. What's more, money and funding are usually an issue and pictures are the things that grab people's imagination and make things popular. The Voyager probes only had 1970s technology but their pictures of Saturn were very popular

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Re: APOD: A Landslide on Asteroid Vesta (2011 Nov 28)

Post by Flase » Thu Dec 08, 2011 8:12 am

What's more, what is the point of such a mission? Obviously scientific data is one important reason, but what is the point of science? Surely it's for the whole human race, including laypeople.

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Re: APOD: A Landslide on Asteroid Vesta (2011 Nov 28)

Post by owlice » Thu Dec 08, 2011 9:34 am

Flase wrote:Well it's a shame. Most of the pictures of Mars that you get are recreated from computer models and just don't look right.
I think the pictures we are getting of Mars are gorgeous!
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Re: APOD: A Landslide on Asteroid Vesta (2011 Nov 28)

Post by neufer » Thu Dec 08, 2011 12:41 pm

Flase wrote:
What's more, what is the point of such a mission? Obviously scientific data is one important reason, but what is the point of science? Surely it's for the whole human race, including laypeople.
http://en.wikipedia.org/wiki/Color_blindness wrote:
<<About 8 percent of males, but only 0.5 percent of females, are color blind in some way or another, whether it is one color, a color combination, or another mutation. The reason males are at a greater risk of inheriting an X linked mutation is that males only have one X chromosome (XY, with the Y chromosome carrying altogether different genes than the X chromosome), and females have two (XX); if a woman inherits a normal X chromosome in addition to the one that carries the mutation, she will not display the mutation. Men do not have a second X chromosome to override the chromosome that carries the mutation. If 5% of variants of a given gene are defective, the probability of a single copy being defective is 5%, but the probability that two copies are both defective is 0.05 × 0.05 = 0.0025, or just 0.25%.>>
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