Detailed Render of the Earth from Space - Blender 2.5 - page 229

To c r e a t e t h i s g ro u p To f n To d e s w e j u s t n e e d t To a d d t h r e e n To d e s :
F Add → Convertor → ColorRamp
F Add → Convertor → Set Alpha
F Add → Convertor → Alpha Convert
7. Once the three nodes have been created, let's connect the image output of the
ColorRamp node into the Image input of the Set Alpha node, then connect the
image output of the Set Alpha node into the Image input of the Alpha Convert
node.
8. Now, let's select the three nodes ( Shift + right-click) and duplicate them twice ( Shift
+ D ) to get three disinct copies. Don't forget to move the new copies to get them
clearly separated.
9. Once the three copies are created, let's select the three nodes of the first copy,
create a group ( Ctrl + G ), and set its name to controlledGlow1 . Then let's create
two more groups with the other two duplicates and name them controlledGlow2
and controlledGlow3 , respecively. It is important to duplicate the nodes before
grouping them, since the three groups will have diferent seings. Keep the groups
around to be used later when needed in the setup.