I'm trying to implement atmospheric glow like this. It was a huge pain to get it done, since I'm new to FBO and OpenGL, but I managed to do something similar to what the OP wanted.
I followed his steps and now I'm rendering the resulting texture to my space environment. However, the texture is completely opaque and I only need the glow parts to be visible. How can I make the rest of the texture transparent? I'm using OpenGL ES 2 on Android.