Abstract: What is a rainbow? How many are there? Why is the sky blue? Why is the setting sun red and flattened? What is a mirage? Why are there rays or spokes coming from the setting sun? What is the green flash? Can it be photographed? Why does the moon look so big on the horizon? Why do stars twinkle? What is an aurora borealis? Is it really darkest before dawn? Why are wet spots dark? What is that ring around the Sun? Why can water appear so many different colors? These and dozens of other questions about naturally occurring optical effects are explained with pictures and diagrams, along with tips on how to see and photograph them. Additionally, a number of curious optical phenomena which have not been well explained or merit further investigation will be shown. David Knight Lynch received a B.S. in Astrophysics in 1969 from Indiana University and a Ph.D. in Astronomy in 1975 from the University of Texas in Austin. He is Senior Scientist at The Aerospace Corporation where he specializes in infrared spectroscopy of comets, novae, supernovae, young stars and very old stars. Dr. Lynch has held research positions at the Sacramento Peak Observatory, Caltech, UC/Berkeley, and The Aerospace Corporation. He has published over 160 scientific papers and 10 books. He has organized 12 international scientific meetings. He is currently with the United States Geological Survey (USGS) in Pasadena, where he studies the San Andreas Fault.