(40 pages) Back in the day ... :) ... before GPS, ships navigated the seas by observing the sky. With this activity, students can do the same. If you know the altitude of the North Star, then you know your northern latitude. If you know when the sun is at the top of its daily arc, then you've determined local noon, and local noon can be compared with GMT (Greenwich Mean Time) to determine longitude. Students use station cards that show day and night sky to determine their daily position during a trip across the Atlantic and back ..... back in the day! :) This is an interesting and fun activity for astronomy students of any age!