Being Easter, perhaps, I feel a little more colorful than normal.

Who wants a free ice cream Sundae?

Be the first to present a public mosaic of our Solar system that is color correct, and I'll treat you to an ice cream Sundae!

I only require the natural color of the Sun and its planets, assuming all light levels to be in the normal color vision range of the eye [added: as would be seen from space]. The mosaic must have already been published or posted somewhere.

[Since Pluto is no longer a planet, we can ignore the lack of knowledge of its color and any mosaic that includes it will still be valid.]

Orange and yellow suns are invalid.

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Lighten up! This is a stellar board! Author: duh.

"The Sun, with all the planets revolving around it, and depending on it, can still ripen a bunch of grapes as though it had nothing else in the universe to do..." Author: Galileo supposedly.

Why is a yellow sun invalid?

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"The only way to explore the universe is to go and look." - Brian Cox
Well, the best way to find out is to go there and, find out. - Raven's Cry
'Evolution and science are one thing, but you don’t mess with Yoko Ono. Everybody knows that. ' - 386sx

A yellow Sun is an atmospheric colorful effect only. You won't see unfiltered Solar projections revealing a yellow Sun, unless the Sun is near the horizon. I hold to a white Sun, but I am hardly alone. If any of these folks have done a mosaic of the Solar system, then the colors might be right.

I strongly suspect, however, that no such near "true color" presentation of the Sun and planets has ever been done. I've got one hanging on my wall. It has no Sun, Venus is orange (from a false color surface image!), and Mars is brown. The more distant planets seem to be very accurate.

I do hope this draws some colorful attention to a colorful problem.

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Lighten up! This is a stellar board! Author: duh.

"The Sun, with all the planets revolving around it, and depending on it, can still ripen a bunch of grapes as though it had nothing else in the universe to do..." Author: Galileo supposedly.

You're making venerachromological comments now! Or maybe that should be cytherochromological. I had the impression that the orange hue was an average of more-or-less true color versions of the Venera surface images, driven almost completely by what spectral slices of sunlight manage to survive the many ricochets through the cloud decks. That would be a defensible surface color, albeit based on limited data and not actually representative of the surface rock if you depict the planet stripped of clouds.

Ah the Easter Bunny has delivered a can of worms. "true colour". As the vast majority of amature astronomers have little choice but to acccept the limits of at least some atmospheric effects, it appears that you have eliminated their ground base observations from consideration.

Kind regards
Matt

I thought the surface was all radar mapping. You may be correct, but, since they never used the word "venerachromological" they may not have been as serious as one might expect.

What I want is a simple, typical color image of Venus as seen from space, which is the color of its atmosphere. It should be yellow with features. Here are some images of Venus taken from Magellan (a little brownish) and from Galileo. Perhaps being copyrighted reduces their popularity with publishers. Is that likely?

I don't know what cytherochromological means. It is not in my heliochromology textbook.

I'm still working on a call-to-arms for the Sun's color. What do you think of this one, "Heliochromology Rampant!"? It has a sort of "Big Bang" sound to it, right? [I still will restrict its use to ice cream socials, maybe. ]

Indeed not, I too am an amateur. The Sun's color is not yellow because of the evidence from ground-based observations. If unfiltered Solar projections, seen terrestrially, are white, including the limb region, thus, how can adding back the scattered blues produce a yellow Sun? Blue and white can not make yellow. [This assumes that the blue color seen in the sky is representative of the net color that is scattered away from sunlight.]

As for the planets seen terrestrially, color correction shouldn't be too difficult since the amount of scattering by our atmosphere is known for various air masses or altitudes of the target.

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Lighten up! This is a stellar board! Author: duh.

"The Sun, with all the planets revolving around it, and depending on it, can still ripen a bunch of grapes as though it had nothing else in the universe to do..." Author: Galileo supposedly.

So, what are you looking for exactly?

Does someone have to find data that gives the emission / reflection spectra lines from spacecraft-derived-only sources and then color-correct space-craft-derived photographs into a mosaic you can see on your screen?

From what I've read, doing this would be further complicated by the fact that different computer monitors often display the same colors differently.

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Talent develops in quiet places, character in the full current of human life.
- Goethe

Jump in with both feet!
- Me, indulging my inner eight-year-old

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"Are you a mad-hatter that just types what he wishes, or have you actually any physics training?"
Occam's Ghost to Grant Hutchison.

A close approximation is fine.

I think the color images we have enjoyed of Saturn from Cassini are very close to "true" color. Similarly, the common images of Jupiter, Uranus, Neptune, and many Mars images are more than likely quite accurate, too. There aren't many natural color images of Venus, but I've seen one Galileo image for Venus that is probably close enough. There are images of Mercury that are probably correct, enough so that most of us here would likely agree upon it. Earth is certainly not a problem.

The Sun presents a little more of a problem, as most do not have a clear onderstanding as to its natural color. Some modern textbooks, however, do state the Sun as being a white star (e.g. Jeff Hester, et. al.). From space, it appears blinding white, which is not an indication of its natural color as seen at a properly attenuated level for our vision, yet since it appears mainly white overhead, and obviously white in space, why not white in a mosaic, even if the publisher doesn't really know just how likely white it really might be?

I've done one, but I am not the best person, especially on my list, that should be offering it. My hope is that someone has gone to the trouble to offer such a mosaic. If none exists, maybe it would be nice to add that to the IYA presentations for next year since it was officially 400 years ago that the colorful surface of any planet, excluding Earth, had ever been observed.

Earth-based observations seem pretty close to the color as seen in space imaging, but they can be tweaked by bumping the colors in proportion to the known losses due to atmospheric scattering.

However, since all of the planets have been imaged with cameras revealing natural color, supposedly, why have I not seen one by now? Since many here have better access than I, then maybe several exist. I'll be glad to pay-up, and its not even a bet.

I would expect the vast majority come pretty close.

I'm not needing perfection, but something close.

Most posters are pretty close, but usually get Venus and the Sun wrong.

Notice that this poster comes close with all of them, but Venus. The Sun is pretty close. [I'm not crazy about he rings around Uranus, but that is beside the point.]

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Lighten up! This is a stellar board! Author: duh.

"The Sun, with all the planets revolving around it, and depending on it, can still ripen a bunch of grapes as though it had nothing else in the universe to do..." Author: Galileo supposedly.

George please correct me if I am wrong... but is the kind of thing that you are after, in a way, the answer to the question... 'Is that what it would look like through the porthole if I was approaching it?'

The sun is a special case since its a bit brightish.... but for the others... is that what you are after? (It is what I would like to see.... to show the kids....)

Nice idea... I hope someone with the time and capability to verify the science finds one....

Yes. I should have qualified "natural" colors in the OP, so let me be clear...

If you were to travel to each planet, how would each appear to you as far as their natural coloration? Since the Sun's surface brightness is too bright, along with possibly Mercury and Venus, then we must use a true neutral filter, or other device (e.g. strobe, pinhole projecton), that would allow us to see the object within the normal photopic (color) vision range. [Objects too bright will always appear white if the colors of the spectrum are included. Once our color cones are maxed-out, white is the result, though at a normal intensity it could easily be any color, including yellow.]

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Lighten up! This is a stellar board! Author: duh.

"The Sun, with all the planets revolving around it, and depending on it, can still ripen a bunch of grapes as though it had nothing else in the universe to do..." Author: Galileo supposedly.

Here is a pictoral guide through our Solar system that is probably close to true color. All of these come from APOD.

Mercury from Mariner 10… http://antwrp.gsfc.nasa.gov/apod/ap030216.html
Venus from Galileo.. http://antwrp.gsfc.nasa.gov/apod/ap040516.html
Earth from Apollo 17… http://antwrp.gsfc.nasa.gov/apod/ap990131.html
Mars per Hubble… http://antwrp.gsfc.nasa.gov/apod/ap990705.html
Jupiter… http://antwrp.gsfc.nasa.gov/apod/ap001226.html
Moons of Jupiter mosaic… http://antwrp.gsfc.nasa.gov/apod/ap970929.html
Uranus per Voyager II… http://antwrp.gsfc.nasa.gov/apod/ap010826.html
Neptune per Voyager II… http://antwrp.gsfc.nasa.gov/apod/ap980221.html

Sun (a bit too yellowish, though)… http://antwrp.gsfc.nasa.gov/apod/ap000925.html
Sun, beautiful colors it is not… http://antwrp.gsfc.nasa.gov/apod/ap051201.html

Here is another example on how to determine star color, including our Sun:
Orion focused… http://antwrp.gsfc.nasa.gov/apod/ap030207.html
Orion defocused… http://antwrp.gsfc.nasa.gov/apod/ap980829.html

The defocus approach accentuates the more natural color of the star. The solar twins I've found seem to be all white when defocused, further evidence for a non-yellow star to place in a near, true color mosaic.

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Lighten up! This is a stellar board! Author: duh.

"The Sun, with all the planets revolving around it, and depending on it, can still ripen a bunch of grapes as though it had nothing else in the universe to do..." Author: Galileo supposedly.

Mariner 10 did not take any color photos, according to an article by Andrew T. Young of San Diego State University, published in Sky and Telescope, May, 1985. In that article he provided swatches of color for most of the planets, along with the Moon, Io and Titan. The swatches were generated from reflectance spectra that were not subject to the limitations of many of the spacecraft.

I will go into it more in a later post, and I will try to scan and upload the swatches.

The swatch for Mercury was much browner than the neutral gray on the black-and-white image shown in the linked page. Let me add that those pages make no claims about the accuracy of color rendition.

Thanks. I should have qualified them. It took a while to make the link list as I went through every APOD image. Ug. By the time I found all that I could, I had forgoten I had even claimed they were near to true color, though that had been my objective.

The APOD link I gave for Mercury, however, is not a typical false color image, at least in any dramatic way. [I know what little color is there is important for scientific study, so l do want to remind others that true color is not much of a great scientific goal. Getting close to true, or natural, color is more valuable for PR and art, than science.] The image may still prove to be pretty close to true color since it is so gray, typical of what we should expect. Is this likely?

In the last hour, I stumbled into the latest from Messenger. I found it on Astronomy's next cover issue, as is shown on their website. Here is one image that may or may not be indicative of what one might see in natural color. It is tempting to think it might be close.

Messenger's MDIS package (one narrow and one wide angle camera) uses 11 filters, which, as they put it, allows them to see "much like our eyes do", though no specific image mentions such a case. It would surprise me to see a near true color image actually reveal much color at all.

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Lighten up! This is a stellar board! Author: duh.

"The Sun, with all the planets revolving around it, and depending on it, can still ripen a bunch of grapes as though it had nothing else in the universe to do..." Author: Galileo supposedly.

Shouldn't this be the natural colour of the Sun? It's on fire, after all.

http://umbra.nascom.nasa.gov/eit/ima..._and_earth.jpg

Tis beautiful.

Since a 2,000K tungsten filament produces a yellow-white glow, what color should a 50,000K to 100,000K CME cloud look like? It won't be orange-red.

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Lighten up! This is a stellar board! Author: duh.

"The Sun, with all the planets revolving around it, and depending on it, can still ripen a bunch of grapes as though it had nothing else in the universe to do..." Author: Galileo supposedly.

Thanks George.

This has turned into a very interesting discussion - and I really enjoyed the links you provide. Best luck with your search.

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Talent develops in quiet places, character in the full current of human life.
- Goethe

Jump in with both feet!
- Me, indulging my inner eight-year-old

*** *** ***

"Are you a mad-hatter that just types what he wishes, or have you actually any physics training?"
Occam's Ghost to Grant Hutchison.

Thanks. This is one of those areas amateurs like me can jump in and help out. It is a fun quest, too.

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Lighten up! This is a stellar board! Author: duh.

"The Sun, with all the planets revolving around it, and depending on it, can still ripen a bunch of grapes as though it had nothing else in the universe to do..." Author: Galileo supposedly.

Here are the swatches from Andrew T. Young's article in Sky and Telescope. Each one is averaged over the face of the respective object. They are in the following pattern:

Mercury Moon Mars

Jupiter Io Titan

Uranus

White background

[img=http://img187.imageshack.us/img187/9541/planetcolorscg7.th.jpg]

Black background

[img=http://img187.imageshack.us/img187/3355/planetcolorsdarkbackgroyg7.th.jpg]

I had trouble getting a decent photocopy, either with the scanner or with my digital camera, so I eyeballed them, looking at the magazine under a light that made the paper look really white, and matching the swatches in my PaintShopPro software.

Mr. Young used the best available reflec