David Levy (The Night Sky: My Life and Hard Times through 40 Years of Observing; Wannabes of the Solar System: Meteors, Comets, Asteroids, Planetesimals, and the Origins of Life), is one of the most successful comet discoverers in history. He has discovered 21 comets, eight of them using his own backyard telescopes. With Eugene and Carolyn Shoemaker at the Palomar Observatory in California he discovered Shoemaker-Levy 9, the comet that collided with Jupiter in 1994. That episode produced the most spectacular explosions ever witnessed in the solar system. David is the author or editor of 29 books and won an Emmy in 1998 as part of the writing team for the Discovery Channel documentary, "Three Minutes to Impact." He is a contributing editor for Sky & Telescope, and SkyNews Magazines.

Since David's first observing session in 1958 at Twin Lake Camp, he has recorded over 13,000 observing sessions. On Friday David will share with us some of the high points and even the low points of these hours under the stars that began with a chance spotting of a meteor on July 4, 1958 and an eclipse of the Sun in 1959. The sessions since then have been a combination of the bad and the good. On June 17, 1963, for example, he wrote that "I got out to observe tonight. And what a hell session it was! The mirror fell out. Ooh!" And the following day, "I was working on it when the mirror fell again and broke the diagonal." He somehow reattached it to the telescope with two tongue depressors and tape, and observed with it that very night. The highest moments have been the comet discoveries, the many predawn hours under the stars, and especially getting to share the sky with others.

On Saturday, David will talk about the "almost-weres" of the solar system, the stuff that was around at the beginning, stuff that tried to become planets but just couldn't. He will also focus on what happens when these rogues get in the way. The cosmic collisions that result have had an enormous effect on the evolution of life. This talk will also consider the three outermost worlds of the solar system: Uranus, Neptune, and Pluto; how they were discovered, and ideas about the future of our studies of the outer solar system.

Visit David's website.