Seasonal Change Animation

[PSUPhysicsStudent]

I would like to be able to change the image file (earth.png) of Earth on a monthly basis so that seasonal ice and snow could be shown in relation to Earth's position with the sun. I used the standard earth.png and altered it 12 times to show the seasonal movement of ice for each month (earthJAN.png, earthFEB.png, etc.). I am currently trying to make 12 Earths (with different names) in the solarsys.ssc file that have a beginning and ending date (like a spacecraft) but its not working.

It only has to work for one year, in other words, I am not trying to have the image file change 'all the time' in celestia.

I'm trying to make an AVI file showing the seasonal change in albedo with different cloud coverage and seasonal ice over the period of one year.

Any suggestions?

[selden]

You'll have to be more explicit about what problems you're having.

Have you looked at Celestia's "console log" for error messages? Type a ~ (tilde) to see it.

Typos often are very hard to find.

[PSUPhysicsStudent]

The first problem is that i cannot get the planet earth to only appear during a specified time period (using 'beginning' and 'ending' elements in the solarsys.ssc file).

[selden]

You'll have to provide a copy of the failing ssc file. There are too many different ways to get it wrong for me to guess which one might be your problem.

[PSUPhysicsStudent]

here is the current file. I added a class element, and changed the location of the beginning and ending elements to the elipticalorbit element all to no avail. At this point i'm just trying to get earth to disappear


"Earth" "Sol"
{
Class "planet"

Texture "11earthJAN1986.png" #"earth.*"
NightTexture "earthnight.*"



# SpecularTexture "earth-spec.*"
Color [ 0.85 0.85 1.0 ]
SpecularColor [ 0.5 0.5 0.55 ]
SpecularPower 25.0
HazeColor [ 1 1 1 ]
HazeDensity 0.3
Radius 6378.140 # equatorial
# Oblateness 0.0034


# BumpMap "earthbump.*"
# BumpHeight 4.5

Atmosphere {
Height 60
Lower [ 0.43 0.52 0.65 ]
Upper [ 0.26 0.47 0.84 ]
Sky [ 0.40 0.6 1.0 ]
Sunset [ 1.0 0.6 0.2 ]
# Sunset [ 0.3 1.0 0.5 ]
CloudHeight 7
CloudSpeed 50 #65
CloudMap "earth-clouds.*" #earth-clouds.*
}

CustomOrbit "vsop87-earth"
EllipticalOrbit {
Period 1.0000
SemiMajorAxis 1.0000
Eccentricity 0.0167
Inclination 0.0001
AscendingNode 348.739
LongOfPericenter 102.947
MeanLongitude 100.464

beginning "2008 01 01"
ending "2009 01 01"

}

RotationPeriod 23.9344694 # 23.93419
Obliquity -23.45
RotationOffset 280.5 # offset at default epoch J2000

Albedo 0.30
}

[selden]

All of Celestia's keywords have to start with a captial letter. Beginning and Ending aren't capitalized in your code.

Starting with a simpler planetary definition might make it easier.

Here's a quick example that works for me:

Code: Select all


"Earth_Before" "Sol" {
   Radius 6378.14

   RotationPeriod   23.9344694
   Obliquity        -23.45
   RotationOffset   280.5

   EllipticalOrbit {
      SemiMajorAxis 1.0
      Period 1.0
      }

   Texture "saturn.*"    # default image before seasons
   Ending 2453361.02917 # 2004 Dec 21, 12:42 UT
}
   
"Earth_Winter" "Sol" {
   Radius 6378.14

   RotationPeriod   23.9344694
   Obliquity        -23.45
   RotationOffset   280.5

   EllipticalOrbit {
      SemiMajorAxis 1.0
      Period 1.0
      }

   Texture "mars.*" # winter
   Beginning 2453361.02917 # 2004 Dec 21, 12:42 UT
   Ending    2453450.02292 # 2005 Mar 20 12:33

}

"Earth_Spring" "Sol" {
   Radius 6378.14

   RotationPeriod   23.9344694
   Obliquity        -23.45
   RotationOffset   280.5

   EllipticalOrbit {
      SemiMajorAxis 1.0
      Period 1.0
      }

   Texture "venus.*" # spring
   Beginning 2453450.02292 # 2005 Mar 20 12:33
   Ending    2453542.78194 # 2005 June 21 06:46

}
"Earth_After" "Sol" {
   Radius 6378.14

   RotationPeriod   23.9344694
   Obliquity        -23.45
   RotationOffset   280.5

   EllipticalOrbit {
      SemiMajorAxis 1.0
      Period 1.0
      }

   Texture "jupiter.*" # default image after seasons
   Beginning 2453542.78194 # 2005 June 21 06:46
}   


[PSUPhysicsStudent]

Thank you SO very much. I guess half of my head is still on vacation. I'll let you know how it turns out. The code you sent is awesome.

[selden]

You're quite welcome.

[PSUPhysicsStudent]

It worked perfectly!

Now all I have to do is create a cel file that does a few fly-bys and then capture it to AVI.

Thanks again!