I made this for Armada 2 (A RTS game from the everloving world of Star Trek) not to mention other familiar worlds ;D
http://cybermindtraveller.freewebspace.com/Armada/bh04.JPG
Heres other renderings...It all uses an transparent additive in the game...not sure how hard it would be to do in Celestia...figure quite simple actually...I'll give it a shot...
http://cybermindtraveller.freewebspace.com/Armada/bh01.JPG
http://cybermindtraveller.freewebspace.com/Armada/bh02.JPG
http://cybermindtraveller.freewebspace.com/Armada/bh03.JPG
The last two are earlier versions...
Heres some of the planets I've been adding...Make the game a damn astronomy lesson for Im through
http://cybermindtraveller.freewebspace.com/Armada/saturn.JPG
an alien vista...
http://cybermindtraveller.freewebspace.com/Armada/star01.JPG
http://cybermindtraveller.freewebspace.com/Armada/mars.JPG
http://cybermindtraveller.freewebspace.com/Armada/merc.JPG
and of course earth...no support for spectural maps in Armada
...
http://cybermindtraveller.freewebspace.com/Armada/earth01.JPG