This Mars video
took about a month to capture. Each of the 140 frames
making up this video is an image captured about every 10
minutes. Each image is comprised of about 100 images
of Red Green and Blue color planes combined digitally.
Since Mars rotates 40 minutes slower each day than earth,
imaging the planet at the same time of night about every 3rd or
4th night gives a complete rotation in about a month.
Several things to note while watching the video. First the
south polar cap is clearly visible on the top of the image
(image is inverted vertically). The polar cap seems to get
larger and more pronounced as more of the water ice comes into
view during the rotation. Second, you can see some light
whitish clouds on the east and western limbs of Mars.
Third, note the dark and light patches on the planet. Some
compare the lighter areas to lower "ocean" areas like on Earth
and the darker areas to "contintents", however this is not
correct. The lighter and darker areas have little to
do with topography or elevation, they are merely less or more
reflective materials. Darker areas have been mostly
swept clean of dust so that you see the darker rocky material
underneath. Also since the images were captured at mars
opposition (closest point) to earth, note that one side of the
planet is darker early on in the video and the other side darker
toward the end. This is due to the fact that Mars is
moving by the earth over the month's worth of images so the
angle of the sun on Mars from Earth's perspective changed.
Also, because atmospheric seeing differed from night to night,
some of the images are sharper than others, hence the
change in quality over time.
