That the sky is blue when the Sun is high in the sky and orange when
low in the sky analogous to the situation on Earth is an important
scientific fact.
For instance on a web broadcast with JPL scientist Dr. Eric Wegryn it
was suggested that modeling suggested the daytime sky should always be
orange or tan, and that this was confirmed by Spirit images. But of
course the color images released then used the wrong filter for
creating a visual color image thereby incorrectly giving the sky a
reddish cast.
A later image using the correct visual light color filters showed the
sky with a pale blue color:

This suggests there is something wrong with the modeling of the color
of the Martian sky.

Several webcasts on the MER missions can be found here:

Exploratorium: Journey to Mars.
http://www.exploratorium.edu/mars/webcasts.html

The webcast discussing the color of the Martian sky is here:

Tuesday, January 6, 2 p.m.
View from Mars
With Exploratorium Physicist Dr. Paul Doherty
Find out what sunsets look like on Mars and what makes the red planet
red with images taken by MERs' cameras.
http://www.exploratorium.edu/mars/mars-040106.ram

Bob Clark