Editing Control of Navigation (section)

====Systematic Observation of the Stars====
This is the foundation. Priestess-astronomers observe the sky every clear night for many years.
They record:
* When important stars rise and set
* The height of stars above the horizon
* Which constellations appear in different months
* The position of a polar star (if one exists)
* The movement of the sun along the horizon through the year

'''How they measure things'''<br>
They could use simple historical instruments:
* Gnomon – a vertical stick used to measure the sun's shadow.
* Astrolabe or quadrant – measures the angle of a star above the horizon.
* Armillary sphere – a model of the heavens used for teaching and calculations.
Over decades this produces extremely reliable star tables.