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mars clouds
Posted: 20.11.2003, 23:39
by MindToAsk
Does anyone have a mars atmosphere {with clouds} definition? I've copied the parameters from Earth but I don't think this works in mars case.
Posted: 21.11.2003, 01:57
by TERRIER
Hello MindToAsk
Here's my complete Mars settings, taken from the solarsys.ssc file of celestia version 1.3.1pre11, while the clouds settings I added to this from the mars-clouds.zip that I originally downloaded from Bruckners site.
Maybe there are better settings for the clouds, if anyone else knows of them?
Code: Select all
"Mars" "Sol"
{
Texture "mars.*"
# Texture "mars8k.dds"
BumpMap "marsbump.*"
BumpHeight 2.5
Color [ 1 0.75 0.7 ]
HazeColor [ 1 1 1 ]
HazeDensity 0.45
Radius 3396 # equatorial
# Oblateness 0.0069
Atmosphere {
Height 30
Lower [ 0.8 0.6 0.6 ]
Upper [ 0.7 0.3 0.3 ]
Sky [ 0.83 0.75 0.65 ]
Sunset [ 0.7 0.7 0.8 ]
# Slightly bluish sunset, as seen in true color pictures
# from Pathfinder
Cloudheight 10
CloudSpeed 0
CloudMap "mars-clouds.png"
}
CustomOrbit "vsop87-mars"
EllipticalOrbit
{
Period 1.8809
SemiMajorAxis 1.5237
Eccentricity 0.0934
Inclination 1.8506
AscendingNode 49.479
LongOfPericenter 336.041
MeanLongitude 355.453
}
RotationPeriod 24.622962
Obliquity 26.72
EquatorAscendingNode 82.91
RotationOffset 136.005
Albedo 0.150
}regards
TERRIER
Posted: 21.11.2003, 02:20
by Guest
I've set mine to...
CloudHeight 8
CloudSpeed 28.8
...which I believe I at one time calculated from some reference. Though at this time I can't recall my source or exact calculations. I imagine some CloudSpeed is more realistic than 0 in anycase.
Posted: 21.11.2003, 03:58
by Tech Sgt. Chen
Guest wrote:
I've set mine to...
CloudHeight 8
CloudSpeed 28.8
...which I believe I at one time calculated from some reference. Though at this time I can't recall my source or exact calculations. I imagine some CloudSpeed is more realistic than 0 in anycase.
I'm not sure if the numbers represented under cloudheight/cloudspeed are commensurate with mph, kph or some other measurement, so I hope this helps.
Cloud height: (approximate) 10 miles/16 kilometes.
Cloud Speed: (approximate) 15MPH/6.7MPS
Reference:
http://www.solarviews.com/eng/pathfind.htm
Post Script: Nice cloud pictures at that URL.
Posted: 21.11.2003, 06:12
by Star Lion
while the clouds settings I added to this from the mars-clouds.zip that I originally downloaded from Bruckners site.
His REAL site or my reconstruction of his site at
http://www.bruckner.50megs.com
How I calculated
Posted: 22.11.2003, 02:18
by Guest
I still can't recall what site I gathered info from. But I remember how I did the calculation.
I took the aprox cloud height and speed data for earth from some site and calculated the conversion factor using Earth's clouds settings in Celestia (not that I know if those are accurate or not). I then multiplied the speed and height listed for Mars by my conversion factor.
Can anyone chime in that knows what cloudheight and cloud speed are actually measured in?
Posted: 22.11.2003, 02:55
by granthutchison
CloudHeight is in kilometres. CloudSpeed is in degrees per day (which makes sense given that the cloud texture rotates as a unit, so there is no fixed value that could be assigned for its speed in kilometres per hour).
Martian clouds seem to be at altitudes around 10-15km. Martian weather fronts pass over at 3-day intervals in temperate latitudes, so the CloudSpeed shouldn't be too far different from Earth's.
I guess it depends on what texture you're using, but one disadvantage to rotating the Martian cloud texture is that many cloud features on Mars are topographic - around the volcano summits and maybe also mist lying in the depressions. So you'll move those out of register with the underlying terrain. I tend to turn off cloud movement on the Earth, too, because I hate seeing a ghostly cloud outline of the Andes lying in the middle of the Pacific or the Atlantic.
Grant
Posted: 22.11.2003, 12:54
by selden
This obviously indicatea a situation where multiple cloud layers would be useful...
Posted: 22.11.2003, 21:18
by MindToAsk
TERRIER I'm using your settings now, thanks a lot!
Star Lion Some of the links here
http://www.bruckner.50megs.com, including mars clouds, don't work.
Thanks for the link
Tech Sgt. Chen
Does mars really need a specular map?
Posted: 29.11.2003, 09:34
by Bob Hegwood
Pink stratus clouds are coming from the northeast at about 15 miles per hour (6.7 meters/second) at an approximate height of ten miles (16 kilometers) above the surface. The clouds consist of water ice condensed on reddish dust particles suspended in the atmosphere. Clouds on Mars are sometimes localized and can sometimes cover entire regions, but have not yet been observed to cover the entire planet. The image was taken by the Imager for Mars Pathfinder (IMP) on Sol 16 about forty minutes before sunrise showing areas of the eastern Martian horizon. (Courtesy University of Arizona)
Got the above from the Pathfinder site... Maybe this helps?
Take care, Bob
Posted: 29.11.2003, 19:20
by Bob Hegwood
For your further edification, I'm using the following on my system with satisfactory results:
Code: Select all
Atmosphere {
Height 30
Lower [ 0.8 0.6 0.6 ]
Upper [ 0.7 0.3 0.3 ]
Sky [ 0.83 0.75 0.65 ]
CloudHeight 16
CloudSpeed 45
CloudMap "mars-clouds.png"
}Hope that helps...
Take care, Bob