There's also the old concept of spun liquid mirrors, (1994, Amateur Scientist column of Scientific American): https://optica.machorro.net/Optica/SciAm/LiquidMir

There's also the old concept of spun liquid mirrors, (1994, Amateur Scientist column of Scientific American): https://optica.machorro.net/Optica/SciAm/LiquidMirror/1994-02-body.html https://optica.machorro.net/Optica/SciAm/LiquidMirror/1994-0...