USCG Celestial Navigation Practice Exam

In low latitudes, the behavior of the full Moon is heavily influenced by the Earth’s tilt and the Moon’s orbit around the Earth. A full Moon occurs when the Earth is situated between the Sun and the Moon, allowing the entire face of the Moon to be illuminated by sunlight.

In this context, a full Moon typically rises around the time the Sun sets. This is because, at full Moon, the Moon is positioned directly opposite the Sun in the sky. As the Sun dips below the horizon, the full Moon rises on the opposite side. This phenomenon occurs consistently in low latitudes, where the angles of celestial bodies can be more predictable due to the position of the equator.

Understanding this pattern is crucial for celestial navigation, especially in low-latitude regions, as it helps navigators accurately predict lunar positions in relation to solar observations.