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Global True Color View Of Venus?
ugordan
post Jun 2 2009, 10:43 AM
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Yep, and every time I see a montage of all solar system planets with Venus depicted by the brown-red Magellan surface globe, I die a little inside...

*cough*Photojournal*cough*


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tedstryk
post Jun 4 2009, 09:42 PM
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QUOTE (ugordan @ Jun 2 2009, 10:43 AM) *
Yep, and every time I see a montage of all solar system planets with Venus depicted by the brown-red Magellan surface globe, I die a little inside...

*cough*Photojournal*cough*


The coloration is based on Venera images from the surface, not the cloudtops. Granted, the coloration is due to the filtering of light in the atmosphere, but if we are going to be anal about coloring it like we would see it from space, then the clould should be covering it as well. I will add that the color is still a bit red, mostly owing to the fact that the Venera images have been better calibrated since the Magellan mission ended.


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ngunn
post Jun 4 2009, 10:18 PM
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QUOTE (tedstryk @ Jun 4 2009, 10:42 PM) *
coloring it like we would see it from space


Late night trivia I know, but I'm anatomical about this too. If the viewpoint is out in space then indeed the image should show what would be visible from there - if the aim of the image is to inform the public directly. Other kinds of image useful for scientific purposes that strip away atmospheres, represent invisible frequencies using visble colours, stretch contrast, or vertical scale, should be accompanied by health warnings if posted on public websites. The latest VIMS paper is exemplary. The images come with an explanation of what the colours stand for in each of the two ways the data are represented. It's clear that they do not mean "this is what it would look like". Making an artificially coloured radar map serve as the 'appearance' of Venus is a travesty. (Don't look too closely, it may also be vertically exaggerated.)
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Stu
post Jun 4 2009, 11:21 PM
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QUOTE (ugordan @ Jun 2 2009, 11:43 AM) *
Yep, and every time I see a montage of all solar system planets with Venus depicted by the brown-red Magellan surface globe, I die a little inside...


Every time - EVERY time - I start work on a new kids book about space I have a fight with an editor who is adamant that they should use garish false colour images of the planets instead of more accurate ones. That bloody psychedelic Voyager pic of Saturn is one I have to argue against, as is the UV pic of detail in venus' clouds. Oh. and they just lurve the migraine-inducing false colour Voyager shots of Uranus too... mad.gif


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tedstryk
post Jun 5 2009, 10:21 AM
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QUOTE (Stu @ Jun 5 2009, 12:21 AM) *
Every time - EVERY time - I start work on a new kids book about space I have a fight with an editor who is adamant that they should use garish false colour images of the planets instead of more accurate ones. That bloody psychedelic Voyager pic of Saturn is one I have to argue against, as is the UV pic of detail in venus' clouds. Oh. and they just lurve the migraine-inducing false colour Voyager shots of Uranus too... mad.gif


I agree with the false color Voyager shots. However, if you are going to show Venus the way it looks from space, you shouldn't show it from the surface at all. Using the rough apparent color of the surface to a viewer under the clouds who can actually see the surface should not be put in the same league with this.


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Juramike
post Jun 5 2009, 11:08 AM
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Personally, I don't like the wavelength limitations of visible light. Hyperspectal imaging, false color imaging, topgraphical coloration, mineral maps based on diagnostic bands - all these things make comparisons and contrasting of features easier (and pretty!).

But I totally agree with the points above: if you are going to show false color or enhanced images, it is important to put a warning lable that they are false color views. And if you are going to show a set of comparison images of planets, they should be all treated similar. If you strip the atmosphere and clouds off one of the terrestrial planets (like Venus), you need to do it for the other similar planets.

If you are only going to show the upper atmospheric structure of Venus, Earth's also needs to be shown for a comparison (but obviously not using the the same technique). [How are they similar? How are they different? Why?]

I always thought the perfect kids book would show a topographic representation of the terrestrial planets for comparison:
["Gee, without water, Earth still has ocean basins and continents....how come the other worlds don't have this? And what's going on with that ridge going down the Atlantic basin? How come Mars has those deep holes? Why are parts of the Moon so smooth?"]


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Some higher resolution images available at my photostream: http://www.flickr.com/photos/31678681@N07/
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tedstryk
post Jun 5 2009, 01:51 PM
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I would say that there is a difference between false color imaging that shows, say, infrared wavelengths, so that the colors contain real information that can't be conveyed in a "true" color image and images that are simply colorized to look "cool." Juramike, I fully agree on the visible light issue. Our eyes evolved for our purposes here on earth, but there is so much to be gained from adding non-visible wavelengths. That is why I really prefer to call , for example, a color-shifted Voyager image G-V-UV color instead of "false" color. It isn't entirely false, in the sense that the colors really do mean something.


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Stu
post Jun 5 2009, 01:58 PM
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The problem I encounter is that editors want to use a garish false colour pic without explaining that it IS false colour, which would obviously lead to young readers being led to believe that Saturn really is decorated with poster paint blue, red and green clouds. I once had to fight - not literally! - with an editor to have a false colour view of Victoria Crater (you know, one of the "everything looks blue" images) removed and replaced with a natural colour one, because they wouldn't give me room to explain the nature of the pic. That would have meant a big header saying "Mars - the Red Planet" with a picture of a kingfisher-blue cliff face beneath it... rolleyes.gif


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tedstryk
post Jun 5 2009, 04:41 PM
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I agree, but I still think that showing the Venusian surface as it would appear in the light that filters through the atmosphere much less "deceptive" than the examples you use, especially when the image is a radar image, so it isn't going to be visually realistic no matter how you portray it.


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Stu
post Jun 5 2009, 05:40 PM
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It's this image I have had to fight to stop editors using...

http://www.pietro.org/images/VenusByPioneer.jpg

sad.gif


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tedstryk
post Jun 5 2009, 05:44 PM
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Not only is the color bad, but that is a Mariner 10 image.


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Stu
post Jun 5 2009, 05:52 PM
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Okay, but you get the idea, right? Editors can be hard to convince; they're - understandably - looking for visual impact, something to grab the attention of young readers, and once they've found a "wow" pic to use (don't know how they managed before Google!) you almost have to wrestle it out of their clutching hands...


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brellis
post Jun 5 2009, 08:42 PM
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When's Google Venus gonna be up and running? smile.gif
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tedstryk
post Jun 6 2009, 10:16 AM
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Yes, I get the idea. However, to me, the fact that a lot of Magellan imagery is shown with 20x vertical exaggeration is in that category, but using Venera-based colorization isn't.


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scalbers
post Oct 15 2010, 09:12 PM
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Is this web page with a Venus image showing some real data or an artistic work?

http://rocksfromspace.open.ac.uk/Venus.htm

If I can find a "full" Venus image I can try to see what it looks like with Science On A Sphere.

Thanks,

Steve


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