For up to five extra credit points:

 Explain in a paragraph with a diagram of the sun (or light source) 
 and observer any of the following atmospheric optical phenomena:

 sun pillar
 corona
 glory
 broken bow
 green flash

 You may use the book as a starting point.  However, relying completely on your  book will not get you points!  
 List your references 
 - reputable internet sources such as educational and university 
   websites are fine.