Trina Habercom

I hope someone can help me ..Ive done some building but Im really an amateur. I've got a 50*50*50 phantom hollow sphere. Ive sunk this in the ground to create a hollow dome. The inside surface is textured with a night sky and the outside surface has the default colour and texture , this outside face I've set tranparency to 100% . This works great except for an irritating problem . When looking from outside I can see part of the inside night sky textured surface. I really want the dome to be totaly invisible from the outside so that all the contents of the dome can be seen. And then as people walk through the invisible dome they magically find themselves in a stary night setting. Anyone got any ideas? The reverse is dead easy ..a full ( not hollow) phantom textured sphere!