I have worked on sprucing up some global views of Europa from Galileo. There are a few more global views I hope to get to eventually. But the best two at nearly full phase benefited a lot.



[Moderator note: There are several more threads containing Galileo Europa images but they all contain several inactive image links. The main threads are:
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http://www.unmannedspaceflight.com/index.php?showtopic=2174
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Wow, I do believe that bottom one is the most spectacular view I have ever seen of Europa. Well done! Is that one true color? Interesting to contrast it with what Voyager saw.

Yup. Verrrrrry good!

That Voyager view is the best color mosaic view, but the image quality of that version is poor. A bit fuzzy and with a bad color-cast.

WooHoo! My favorite LittleMoon! I love Europa.

In my galileo mosaic, the color data is a mixture of two band data from the orbit, as well as a crude reprojection of data from other orbits. So the Voyager mosaic is best.

In my galileo mosaic, the color data is a mixture of two band data from the orbit, as well as a crude reprojection of data from other orbits. So the Voyager mosaic is best.

I think the super-res effect really helped them.

I am also working with Voyager...Here is the best Voyager 1 set, in OGB color.

I have worked a bit more....I am having OGB Voyager problems. To the right is the image as produced through standard processing. To the left is a version edited to try to look more like a Galileo image.

I just made an exciting "discovery" - well, a discovery to me...there is one more global color view in the Galileo set from the C10 orbit. I am surprised this hasn't been used more. The Color is IR-7560-Green-Violet. However, the green image clips the terminator, so that area is filled in with a synthetic green from the IR-7560 image and Violet image. The black and white image is a combination of a super-resolution image produced from the IR-9680, IR-7560, and Violet image, all of which were transmitted after being binned 2x2, and, for the areas available, the green image was then merged creating an even better product.

Ted - fabulous! Keep it up!

Phil

These can be compared with the cylindrical map that is on my website at http://laps.fsl.noaa.gov/albers/sos/sos.html#EUROPA

That map is awesome...I hve spent much time admiring it.

As for the color mosaic, I have tried many times to make it, but I have hit pitfalls. First, the lack of green data on the terminator. Second, when I try to fill it in with lower resolution data, it looks odd, since the green image is the only one sent back at full resolution. Third, the albedo patterns looked wierd, because the green filter data was used as for the grayscale. By making a super-res image from the binned imagery, I was able to prevent a great resolution drop on the terminator and was able to make a more realistic grayscale image without degrading it with low resolution input. By overlaying the green image over a synthetic green created from violet and IR data, I was able to make the end of the green image less noticeable.

The only other galileo global shot of Europa was from the e17 orbit. I have crudely matched it with other color data here...I will put more time into this someday. I also plan to eventually work on the G1 data and merge it with some other data for a global view.

Ditto. My silence belies awe and gratitude.

John

Ted,

Your images are very nice as well, particularly the large gibbous view in post #1. One thing in particular I'd consider is comparing the hue and saturation realism to what I had used, namely the colors from Bjorn's map (that I may have tweaked a bit). Do you have a feel for the pros and cons of the color accuracy compared with Bjorn's? Both look pretty good to me - I wonder what new insights you have come up with. I'll reread your posts as well.

nice work on europa guys. It is so cool to see the images being properly reproduced instead of horrid stuff you still see in text books.

Be careful of that image. The filter sets available were limited at best, and those used to produce the image vary throughout. Plus, some color data is from the actual set the grayscale image was made from, but a lot of it is from different orbits at different illumination angles. So the color, while processed to seem roughly realistic, is quite treacherous - a lot of guesswork went into it, and then I normed it a bit to fit the other images. As for the others, they are as accurate as I could make, but I can't directly compare them because I don't know how Bjorn's color was produced.

How about trying the same with images of Io?

I have thought of that. The only problem is that Io has much more color contrast than Europa (europa has some color contrast, but it is pretty predictable - Io's isn't). I am not sure if it would come out well or not. I may try.

Keep them coming! Europa really deserves an orbiter.

Well, I might work on some other moons, or try some mosaics. This is the only other global view of Europa I could find in the Galileo set that was worth combining with some color data.

Regarding my Europa map, the color there was taken from global Voyager images only. I used these to colorize higher resolution grayscale data (mainly clear filter). The reason I used Voyager and not Galileo data was higher resolution and IIRC Galileo had not imaged Europa globally in color at the time I made the map. I don't remember whether I used OGB or OGV (probably the latter) - I'm at work and can't check it now.

I'm pretty sure the color is a bit too saturated in my map. It may too reddish as well, a common problem when the wavelength of the data used for colorizing is too short (e.g. O instead of R and/or V instead of B ).

I have been working on a much bigger Europa map (9000+ pixels in the horizontal direction) from time to time for more than two years. I have reprojected most of the high-res data I plan to use but haven't started working on the color. I plan to use Galileo images for color where possible, filling gaps (or very low-res areas) with Voyager data and/or synthetic color. I also expect to use synthetic B instead of V. The V images are more contrasty than the B images but mixing G and V should give a fairly good results (definitely better than using V only). One thing that complicates color work is Europa's photometric properties, limb darkening varies with wavelength and I prefer images as close to zero phase angle as possible.

Ted's images look fairly good, especially wrt sharpness but there are some saturation problems, caused both by saturation in the red images (this manifests itself as pinkish areas) and in all of the images in some cases (bright, white areas). I have some early 'test images' of Europa that look similar. And I should add that there is great color data at 1.4 km/pixel in the E14 data.

BTW Europa's color should be kid's stuff compared to Io. There is some information on Io's color on my experimental renderings page ( http://www.mmedia.is/bjj/3dtest/ ) and I will add more once I make my new map of Io available, I've been too swamped in data recently to update my website . In particular, it is impossible to use 'unmodified' IR7560 as red without seriously messing up the color balance.

If you consider the Galileo filters and their wavelenghts, you have:

Violet - 404 : Green - 559 : Red - 671 : IR756 - 756 : IR968 - 968


The human color vision has a peak response of:

Blue - 440 : Green - 510 : Red - 650


So to "convert" the Galileo filters in to "human colors" we can mix images from different filters to get the proper wavelenghts.

I've calculated the ratios and corresponding wavelenghts:

75% Violet + 25% Green = blue (443)
70% Green + 30% Violet = green (513)
80% Red + 20% Green = red (649)
50% IR756 + 50% Green = red (658)
20% IR968 + 80% Green = red (641)


I've tried this on two Europa images and the results look good. Saturation is low, but that's expected when you mix the color data. Also, Europa looks white through a telescope anyway ;-)

Click to view attachment

Click to view attachment

I experimented with filter mixes. Realistically, the problem is that Galileo image quality varies wildly depending on compression used. Also, it is rare to get a color mosaic without some bad gaps. But I did use similar mixes.

Bjorn: I see the problem in my large mosaic, but could you point out what you are talking about in my other images? I am not sure which spots you are referring to, and would like to know so I can try to correct the problem. Some of what you are seeing may be due to the fact that I jacked the contrast up on the posted images.

The pinkish areas are very prominent in the C10 image (the message dated yesterday at 05:29 PM), especially in the bright areas near the left limb and near Pwyll.

This is a tweaked version.



And another.

These are better but still a bit pinkish. I'm not sure why - now that I'm at home and can have a look at what happened when I was processing these same images a few years ago I see I also had some problems with pinkish areas, especially near Pwyll. They were less pinkish but still pinkish.

Time to try to finish that 9816 x 4908 map of Europa I have been working on for two years, I should be able to get more realistic color for that map. I have now checked and seen that my current map of Europa was colorized using OGV as I thought. This means it is probably too reddish and saturated.

It is probably an interesting idea to check if there are any Cassini RGB (or CB1-GB) images of Europa near closest approach.

If you try the CICLOPS site and use their new search feature for "Europa" a couple of nice (if small) color images will pop up.

Some "True Color" Images of Europa.

Somthing I found looking around. http://pirlwww.lpl.arizona.edu/HIIPS/EPO/gallery.html

This could bode well for life on Europa (and Enceladus?):

Scientific American, 30 September 2005

http://www.sciam.com/article.cfm?chanID=sa...A8E83414B7F4945

Geologists have produced evidence of abundant marine life on the earth from a
period when others say a thick layer of ice gripped the entire planet. The find lends
considerable support to one side of a scientific controversy that has been widely debated for
decades.

The hullabaloo is over a glacial period dating to about 750 million to 600
million years ago.

Experts agree about the presence of ice on the planet then--even at the
equator--but how much and to what extent is still up in the air. Theories range from a "snowball
Earth" hard packed in kilometer-thick ice to a "slush ball Earth" characterized by thin ice and
areas of open water. The range of conditions would have impacted the microorganisms present.

Thick ice would have made life difficult for plants and animals, one line of reasoning goes,
choking oxygen out of the sea and blocking sunlight needed for photosynthesis. Mass extinction
would ensue and after the thaw, give rise to an explosion of multicellular life.

Has anyone here cleaned up this picture? It one of my favorite images of Europa http://photojournal.jpl.nasa.gov/jpeg/PIA02528.jpg

Here is a rendering using my map.

WOW! Keeping that one!

Have anymore? Webpage?

So many moons and planets, so little time.. perhaps the Planetary Society will get enough money for a close inspection of Europa sometime soon.

Europa has always capture my imagination.

I even dream of swimming around its oceans!

This leads me to a kinda off topic question. Has Europa ever been in a Hollywood movie besides 2010?

Decepticon,

I don't have a website but I have contributed many maps to Calvin Hamilton's Views of the Solar System. The above Europa image is created using the map at:
http://www.solarviews.com/eng/eurmap.htm

Thanks!

Great work! I have always enjoyed your work on Views. Great to see you in this forum!

Thank you all for the time and effort put into these beautiful Europa products! Ted, your E14-based Europa color mosaic is amazing. Sorry we couldn't get you that green-filter near-terminator strip returned to Earth....

-Bob P.

Can you imagine how many spacecraft we could build if France, the UK, Russia, and the US stopped building warplanes for just one year and diverted the money to space hardware? I know that's totally fanciful, and I know we need planes, and our military plays a vitally important role (and my son is a helicopter pilot in the US Army)...but would it really "kill" us to go one measly year without building new ones? We could fund many of the projects we would so dearly love to do. Think how much we could learn about our solar system!

Add it to your New Year's wish list!

Has anyone totalled up the surface area of the moons and major asteroids, even just a rough order of magnitude, and compared it to the Earth's surface area? Isn't it amazing to think about how much unexplored territory there is in our solar system? Once we get the technology to visit them, the human race will be busy for decades crawling over every nook and cranny.

Answering my own question: counting only the terrestrial and icy planets and moons, and not including any asteroids, comets or KBOs, the total surface area of the non-Earth "solid" solar system objects is roughly 281.7 million square kilometers, or about 2.2 times the total surface area of the Earth (including the oceans).

That seems low somehow.

But assuming it's correct, and assuming that an astronaut could explore 10 km^2 of surface area per day, it would take 28 million "person-days" to explore the surfaces of the moons and planets in our solar system. That sounds like steady employment well into the next century.

Here's a challenge that I hope one of you might accept. During the E12 Galileo orbit, there was a sequence of Galileo color images obtained of Conamara Chaos. Below is work by the Galileo SSI team to assemble these into color mosaics. This color imaging is enough to paint much of the famous E6 Conamara Chaos mosaic in true color (or near-true color extrapolated from 2 colors)--unfortunately we still only see this region painted by false bluish color based only on the E4 Europa albedo images. Can someone accept the challenge of painting Conamara with its true E12 color?

-Bob P.

Does anyone know what the composition of those brown areas are?

And did they come from the ocean floor?

Im certain it would be possible to do that, I did some fast dabbling with the small one you provided, but as soon I zoomed in I noted the jpeg noise and well...at least I would feel it more rewarding to spend time on if one had a larger sized image than that so one wouldnt get artifacts from masking the various parts.

I include the quick dabbling I did for reference though.



Edit: Images where each colour channel would be separated would of course be the very best.

Most of that must be Venus (9/10s of Earth's total area, including oceans; a vast territory to explore, if one could only get to it -- drat that Venusian atmosphere!).

Given that Mars' surface area is about the same as that of the whole land area of Earth, and the Moon's is about the size of Asia, and there are only five bodies intermediate in size between Mars and the Moon, yeah, that seems about right.

Probably sulfur-rich materials from charged particle bombardment of salts and/or sulfuric acid hydrate, which in turn may have churned upward from Europa's ocean. But no one is sure... part of why we need a new mission, with a better spectrometer.

Here is blue

...and green...

...and red (near-IR, really).

Thank you vexgizmo for the samples, since the last one was near ir, and only covered a smaller part of the area I ended up working on two colours. Part reason was that while working on the image I noted that some stripe of the blue channel was out of aligment, seems to me it was one layer below where two others images have been pasted on top.



But not entirely certain, I adjusted that at best of my ability though. In the end we see one completely unscientific interpretation of mine.