Moon phases are the result of the changing illumination of the lunar disc as the Moon orbits Earth, completing a synodic cycle of about 29.53 days. Mariners have long used the visual appearance of the Moon to estimate the time of high water and to aid dead‑reckoning when celestial bodies are obscured.
The gravitational pull of the Moon (and to a lesser extent the Sun) creates tidal bulges that travel around the globe. When the Earth, Moon, and Sun are aligned (new or full Moon) the bulges reinforce each other, producing spring tides; when they form a right angle (first and third quarters) the bulges partially cancel, yielding neap tides.
By calculating the lunar age for a given UTC date and time, a navigator can predict the phase, identify the likely tidal condition at a coastal station, and adjust course or timing accordingly.
How does the Moon's gravitational pull affect tides?
What is a synodic cycle in moon phases?
How can mariners use moon phases for dead-reckoning?
What is the difference between new and full Moon in terms of tides?
How does the calculator help with maritime navigation?
Can the calculator be used for any other purposes besides navigation?
Results are for informational purposes only and do not constitute professional advice.