A Child's Introduction to the Night Sky, by Michael Driscoll
Constellations Activity Book (Color and Learn), by Ryan Jacobson
Cosmic Odyssey: How Intrepid Astronomers at Palomar Observatory Changed Our View of the Universe, by Linda Schweizer
Eyewitness UNIVERSE
Find the Constellations, by H.A. Rey
How I Killed Pluto, and Why It Had It Coming, by Mike Brown
National Geographic Kids Readers: Planets, by Elizabeth Carney
National Geographic Little Kids First Big Book of Space, by Catherine D. Hughes
Palomar Mountain (Images of America), by Brad Bailey
Simply Astronomy
Space!
Stars and Planets (Peterson Field Guides), by Jay M. Pasachoff
The Magic School Bus Lost In The Solar System, by Joanna Cole and Bruce Degen
The Perfect Machine: Building the Palomar Telescope, by Ronald Florence
The Warped Side of Our Universe
There's No Place Like Space (Cat in the Hat's Learning Library), by Tish Rabe