File:Moon rotating thirdquarter 220px.gif
Moon_rotating_thirdquarter_220px.gif (220 × 220 pixels, file size: 5.5 MB, MIME type: image/gif, looped, 240 frames, 9.6 s)
Captions
Summary
[edit]DescriptionMoon rotating thirdquarter 220px.gif |
English: Animated rotation of the earth's moon. The moon is shown constantly lit from the left (third quarter), like an observer following the earth in its orbit would see it. On earth, only one side is visible, but the moon rotates relatively to the sun during one month. In order to render the animation of a full rotation, images from spacecraft beyond the moon had to be used. At the terminator in the image center, craters can be seen most clearly. Caution: Do not use this version on Wikipedia, as it will take a long time to load due to its large file size. |
Date | |
Source | Own work |
Author | Geek3 |
Other versions |
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Source Code
[edit]The frames of the animation were created with POV-Ray, a free 3D rendering program. Two components are required:
- A surface color map, free image from NASA's 1994 Clementine mission.
- An elevation map (from USGS, public domain) with grey values encoding surface altitudes. The elevation map can be used as a simple bump map for fast rendering, or (as in this case) to reconstruct a full 3D model with realistic shadows.
Executing POV-ray rendering:
povray +H220 +W220 +UA +AM1 +A0.03 +R6 +KI0 +KF1 +KC +KFI1 +KFF240 +Oframe Moon_rotating_thirdquarter_220px.pov
Assembling the gif animation with ImageMagick:
convert -loop 0 -delay 4 -dispose background frame???.png -channel alpha -threshold 50% +channel +dither -colors 256 Moon_thirdquarter_full_220px.gif
Source file Moon_rotating_thirdquarter_220px.pov:
// Moon_rotating_thirdquarter_220px.pov
#version 3.7;
#include "colors.inc"
global_settings { assumed_gamma 1 }
camera { location <0, 0, -220> look_at <0, 0, 0> up 0.00526 right 0.00526 }
light_source {
<2,0,0> * 200
color White
parallel
point_at <0,0,0>
}
// use true 3D surface
#include "functions.inc"
#declare ele=function{
pigment{
image_map{
jpeg "moon_elevation.jpg" map_type 1 interpolate 2
}
}
}
#declare rs=0.006; // ratio of roughness to radius
isosurface {
function { f_sphere(x,y,z, 1) + rs * (1 - ele(x,y,z).gray) }
contained_by { sphere {0,1.01} }
accuracy 0.00001
max_gradient 1.2
texture {
pigment {
image_map { jpeg "moon_surface.jpg" map_type 1 } }
finish {
ambient rgb 0.006*<1,1,1> // space is dark
diffuse 1.9 // brightness
brilliance 1.0 // seems most realistic
}
}
scale <1,1,-1>
rotate <0,-90+360*clock,0>
translate <0,0,0>
}
Licensing
[edit]Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license is included in the section entitled GNU Free Documentation License.http://www.gnu.org/copyleft/fdl.htmlGFDLGNU Free Documentation Licensetruetrue |
- You are free:
- to share – to copy, distribute and transmit the work
- to remix – to adapt the work
- Under the following conditions:
- attribution – You must give appropriate credit, provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use.
File history
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Date/Time | Thumbnail | Dimensions | User | Comment | |
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current | 00:26, 23 March 2016 | 220 × 220 (5.5 MB) | Geek3 (talk | contribs) | == {{int:filedesc}} == {{Information |Description ={{en|1=Animated rotation of the earth's moon. The moon is shown constantly lit from the left (third quarter), like an observer following the earth in its orbit would... |
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