▪ shepherd satellite - A small moon at the edge of a ring system that gravitationally maintains a sharp edge to the ring. Shepherd satellites have been discovered in the ring systems of all of the jovian planets. ▪ superior conjunction - a planet is in superior conjunction when it is on the opposite side of the solar system from us. We see it in the same direction as the Sun, but behind it. Of course, the planet is completely unobservable at this time. ▪ supermoon - no such thing. I think it’s something Fox News came up with. They claim that when the Moon is at perigee and Full, it appears remarkably huge. It is really not appreciabley larger than any other Full Moon. ▪ syzygy - ah… that most wonderful of Scrabble words. When three astronomical bodies are in syzygy, they all line on a single line. It happens at all total eclipses, whether solar or lunar.