{HEAD ~ A first reflecting surface} of an ellipse group reflecting surface preferably has a first focus on the light source and {TAIL ~ a second focus}, capable of being inserted in or removed from an optical path from the light source to a second fixed reflecting surface 
preferably has
{ HEAD ~ A first reflecting surface } of an ellipse group reflecting surface preferably has a first focus on the light source and { TAIL ~ a second focus } , capable of being inserted in or removed from an optical path from the light source to a second fixed reflecting surface
HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH REL REL OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH