Flashcards in Chapter 3 defining units of measure Deck (7)
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1
Ptolomy
The Greek philosopher Ptolomy plotted latitude on a map as degrees north from the equator as did many others
2
On land
longitude can be determined through astronomical observations and surveys (still hard to do)
3
On sea
longitude requires a clock to measure time as well as the measurement of the positions of celestial objects (e.g. Sun)
4
The challenges
Earth rotates 360° per day or 15° per hour
5
About the earth
You find longitude with stars and a clock
6
Chronometers
These early clocks were called chronometers
7
