... The Trifid Nebula from CFHT . ... Also known as M20, this photogenic nebula is visible with good binoculars towards the constellation of Sagittarius. ... Why caused this great white spot on the surface of Saturn's moon Rhea? ... To help find out, the robot Cassini spacecraft now orbiting Saturn broadcast radio waves of three different wavelengths right through the rings to Earth earlier this month. ... Observations of rings bordering the Keeler gap in Saturn's rings showed unusual waves. ...