Finding Your Way by the Light of the Moon
Just as the Sun can help us find our general bearings during the day, so can the Moon at night. For nomadic tribes and travellers, especially in places where movement was difficult in the daytime heat, using the light and position of the Moon was a navigational guide.
During a crescent phase, you can find the general direction of north in the southern hemisphere or south in the northern hemisphere by drawing an imaginary line from the top moon tip to the bottom tip and extend this line down to the horizon. The higher the Moon is in the sky, the more accurate this direction will be.
A waxing or waning Moon can help find the approximate directions of east and west. Since the Moon reflects the Sun’s light, its bright side will be pointing towards the Sun. Between the new Moon and the full Moon, the waxing Moon follows the Sun as it crosses the sky from east to west so its western side will be lit. Between the full Moon and the new Moon, the waning Moon leads the Sun across the sky so its eastern side will be illuminated.
Noticing when the Moon rises and sets in different phases can also roughly tell us the time, remembering it depends on your location on Earth. If you wake in the night and see a third quarter Moon high in the western sky, then you know that sunrise is not too far away. Seeing a full Moon high in the night sky would let you know that it is around midnight.
No matter from where on Earth you observe the Moon its phases occur at the same time. In the southern hemisphere, the waxing illuminated side of the Moon increases from left to right and the dark waning side also increases from left to right. These are opposite in the northern hemisphere and why the moon can be thought of as being ‘upside down’ from the other hemisphere’s perspective.
Southern Hemisphere Waxing Moon
Image credit: Rafael Cerqueira