Okay, this is what I get if I use the standard glass shader.  As you can see, you can see through the side of the glass canopy closest to the camera, but you cannot see anything but black out of the other side.  I have tried different camera angles, thinking it was some sort of refraction problem, but it still did the same thing.  You just see black, no starfield through the other side.  I have never had glass do this to me before...