Martian Sky

[Allan]

I've been doing a buch of looking around on the web to determine what the Martian sky would look like if a man were in the Martian atmosphere. Apparently there's a growing conspiracy that the Matian Sky is not red at all but blue like earths.

Now, I'm no expert in anything related to planets or atmosphere but even I suspect the photoshop conspiracy theorists are off base in asserting the Martian sky is blue. My understanding, and I could be wrong, is that Earth appears blue (and white) because of the oceans on its surface and water vapor prevalent in its atmosphere. The absence of oceans and water vapor and the redness of the Martian soil would cause its thin atmosphere to appear a pale red in my veiw.

For everyones mental tittilation here's one of the less wild links I found http://artsnova.com/blog/2008/02/12/70/

My question..definitively.. is the Martian sky truly red? If its is how red is it?

 

[garyw]

It's butterscotch during the day and it tends to be blue during sunset.

Check out the spirit and opportunity photos to see the various hues of the Martian sky.

 

[Lucy]

For instance; http://en.wikipedia.org/wiki/File:Spirit's_First_Color_Photograph_Mars.jpg

 

[garyw]

Sunset on Mars - note the blue hue:

 

[statickid]

"The Auto Levels command automatically adjusts the black point and white point in an image."

While I do admit those old viking images are probably a little over-saturated...

The conspiracy theory is hogwash :OMG: Obviously these "photoshop experts" are not actually photographers. I can shine a red light into a room and it will appear red to my standard human vision. Then I can pull out my pocket camera, point it at something that I know to be "white" in full spectrum light, and adjust the white point balance to be based on that piece of paper. When I take this photo with an adjusted white point balance everything will appear (somewhat) like it would if I were using a "white light." This is VERY different from what I see with my eye. The most obvious difference is that the paper will look white in the photograph and red to my eye.

Their autoleveler merely shows what the surface of mars would look like if it were receiving a full spectrum of earth atmosphere filtered sunlight. The human eye is optimized to have full earth daylight appear white on a surface that uniformly reflects most of the visual wavelengths.

Perhaps the sky of mars would look blue to a Martian with Martian eyes but when they came to earth everything would look blue as if they were wearing blue sunglasses.:idea:

 

[jedidia]

The Photos are most probably no quite the true color, but that has nothing to do with faking. It's simply more art than science to get the color of photos right when you don't really know under what light conditions they were taken, plus they use lots of filters for photographing different stuff. Here on earth, our brain does the color interpretation of a picture all by its own, based on prior expierience. I.e. we know how things are supposed to look and can therefore tell in which light they were taken. No such luck with the martian landscape and sky. There's a very good post about it somewhere on the bad astronomer.

 

[Turbinator]

The way you take a picture of what the human eye would see, on another planet is to have a perfectly calibrated visible light camera, prior to the mission start. With the mission you also pack the target you you used to calibrate the camera with. Now, when the camera gets to the destination, you take a picture of the camera calibration target, and you note the differences. And those differences that appear, in relation to the calibration done on earth is your baseline for that planet. And now every picture you take, will look as humans would see it, and if you use filters and other such things you can use the baseline you calculated, in order to make the picture look like what the human eye would see.

It is actually very simple.

 

[Suzy]

The Skies Of Mars - seems to be sort of greyish according to this webpage.

 

[jedidia]

It is actually very simple.

not quite so simple I'm afraid. I dug up the post on bad astronomy: http://www.badastronomy.com/bad/misc/hoagland/mars_colors.html

most notably, the rovers DIDN't include an exclusively visible light camera, since a camera merely for pretty postcards could never be justified in the payload budget.

 

[Allan]

I really should stop being surprised by the complexity thats behind the questions I tend to ask. That article from Bad Astrononmy was very enlightening. It also helped return me to my initial question "what color is the sky on Mars".

I have to now suspect that every photo seen is not a "true color" picture since, logically, scientists need to maximize their payloads for maximum data collection.

It seems probable to lean toward to "butterscotch" or maybe a light carmel colored sky or perhaps a watered down light orange hue (from dust?) simply to play the odds favorably for what I'm trying to pen.

I found this link: http://www.donaldedavis.com/PARTS/MARSCLRS.html
It appears to offer good insight to the actual color of the Martian sky.