The MarsDial is a sundial that was devised for missions to Mars. It is used to calibrate the Pancam cameras of the Mars landers. MarsDials were placed on the Spirit and Opportunity Mars rovers, inscribed with the words "Two worlds, One sun" and the word "Mars" in 22 languages.[1]
The sundial design team[2] included Bill Nye "The Science Guy," space artist Jon Lomberg, and astronomers Woodruff Sullivan, Steve Squyres and James Bell.