Terrafromed Mars

[Ariel DK]

Easier to just use two atmospheres and shadow mask them (it will be leagues faster than trying to ramp up v2 quality). That image however is a processed composite, exaggerating atmospheric content (reds have been muted slightly and blues saturated; compositing may come in form of atmosphere xrays), for visualization, it doesn't look like that to the naked eye at all.
(..)

Well i know it haha, if you see at my render, i dont tried to create those exaggerated blue hazes, but as you said before
Mars atmos is not just red, there is some light blue/withe traces on differents zones, thats why i prefered use clouds.
I need to try to get (or create) those files again...

Your study also remains me these images taken by Viking 1, this one also have exaggerated details, but no color retouching:
https://www.flickr.com/photos/132160802@N06/28159597150/in/photostream/

[WAS]

If you use clouds, for haze-type stuff you can put Sample Jitter at 0 and you'll get much faster renders, and less grain. Just figured that out for some tests in my Nu2 Lupi scene. If you're using density shaders it will produce a more exacting look to the noise, without the jitter scattering.

[DocCharly65]

The last 3 are great again. I could not decide which one is the best.