Enter the  Main Exhibit Here Lessons Index: 1. MAP AND CHART 2. CHARTING THE GREAT WINDS 3. RIDING THE WIND 4. THE MAP CARTOUCHE 5. THE GULF STREAM 6. CHART MAKING FOR NAVIGATORS 7. HURRICANES 8. PROFILES 9. CHARTING NEPTUNE’S REALM 10. SURFACE CURRENTS 11. DENSITY CURRENTS 12. CURRENT AND CLIMATE 13. HUMAN INTERACTION 14. DEFINING THE EARTH 15. LATITUDE 16. LONGITUDE 17. COMPASS DEVIATION Osher Map Library University of Southern Maine

Charting Neptune's Realm: From Classical Mythology to Satellite Imagery An exhibition at the Osher Map Library and Smith Center for Cartographic Education, University of Southern Maine, Portland, 4 April 2000 to 11 January 2001 Donald S. Johnson, guest curator Lesson 15e - Presentation of Lesson LATITUDE Osher Map Library Lesson Charting Neptune's Realm Peter Rice, Andy Alley A. Learning Objectives B. Background Information C. Teacher Activities D. Materials Required E. Presentation of the Lesson (Item) (Activity) (Time/Elapsed Time) 1. Opening Statement (1 min/1 min) As sailors began to extend their reach beyond the sight of land and groups (fleets) of ships became larger, it became more and more important that they be able to determine their location. Dead reckoning came first, but around 850 CE the Arabs developed a method of determining the latitude of any location. In this lesson we will examine the theory of finding the latitude, and we will get the opportunity to make an 'Astronomical Table' for this classroom. 2. Polaris (Show transparency of  Polaris/Latitude) (4 min/5 min)           a. Assumption (Polaris due north, rays of light parallel)           b. Calculations 3. Solar (Show transparency of Solar/Latitude) (4 min/9 min)           a. Advantages           b. Difficulty           c. Calculations (Tropics, Equator) 4. Celestial Instruments (10 min/19 min)           a. Astrolabe (Show transparency of Astrolabe)           b. Cross-staff (Show transparency of Cross staff)           c. Octant (Show transparency of Octant) 5. Astronomical Table Experiment (23 min/42 min) Divide the class into groups to record elevation angles with both astrolabe and/or cross-staff. Some students can be used to record data and develop tables to determine angles for every yard (meter) of distance from the wall. 6. Review main points and clarify student questions (2 min/44 min) 7. Closing Statement (1 min/45 min) Discovering a way to determine the latitude on a constant basis was the first step in the ability of the European to sail great distances with some degree of confidence. By knowing the latitude of the destination, the mariner could sail down the latitude to reach the desired port. Without that ability, the commerce that established and maintained the colonies in the New World would have been impossible. Without that commerce, the Boston merchants would never have had the chance to protest the importation of British tea. F. Glossary Return to Lesson 15 Index Return to Charting Neptune's Realm index of lessons Return to Osher Map Library's complete list of lessons on the web