... Cassini Images Saturns A Ring . ... What are Saturn's rings made of? In an effort to find out, the robot spacecraft Cassini that entered orbit around Saturn two weeks ago took several detailed images of the area surrounding Saturn's large A ring in ultraviolet light. ... Ringed Nebulae . ... Cassini Images Density Waves in Saturns Rings . ... The Cassini spacecraft just entering orbit around Saturn has started sending back spectacular images of Saturn's immense ring system in unprecedented detail. ...