Moonrise, Moonset and Meridian Passing Times Calculator – Timehubzone (2024)

FAQs

How do you calculate moonrise time? ›

By subtracting the hour angle of the rising point from the local time of culmination of the rising point, we obtain the time (local to the station) of moonrise. By adding the hour angle of the setting point to the local time of culmination of the setting point we obtaii~ the time (local to the station) of moonset.

A meridian is a location's longitude (a line that runs from the North Pole to the South Pole of Earth). When we use the word meridian, it usually refers to the moment that the Moon crosses or passes a location's meridian; this marks the exact moment when the Moon reaches the highest position in the sky.

The exact times depend on the lunar phase and declination, as well as the observer's location. As viewed from outside the polar circles, the Moon, like all other celestial objects outside the circumpolar circle, rises from the eastern half of the horizon and sets into the western half due to Earth's rotation.

While one sunrise to the next is about 24 hours, one moonrise to the next is about 24 hours and 50 minutes. The extra 50 minutes are due to the Moon's orbit about the Earth. It therefore shouldn't be surprising that there are days where moonrise occurs shortly before sunrise and moonset occurs shortly after sunset.

The Moon rises on an average 50 minutes later each day in Earth's skies due to the difference in Earth's rotation and Moon's revolution. Moon completes one orbit around Earth in 28 days, moving 13º every day. Hence, the Earth has to rotate an extra 13º every day after completing one rotation for the Moon to be visible.

Because the Moon is constantly in motion, the time span from one moonrise or moonset to the next is a little longer than 24 hours. For example, if the Moon rises just before midnight on day 1, it may not rise again until just after midnight on day 3, meaning that day 2 does not have a moonrise.

The meridian passage is the moment when a celestial object passes the meridian of longitude of the observer. At this point, the celestial object is at its highest point. When the Sun passes two times an altitude while rising and setting can be averaged to give the time of meridian passage.

The Moon orbits the Earth about once a month. The Earth, however, revolves around its polar axis once a day, every day, and so every meridian passes the Moon every day.

What time is the full moon on the meridian high in the sky at transit? ›

So, at sunset (about 6:00 PM), the full Moon is rising. Six hours later, the Earth has rotated an additional one quarter of the way around. Now, the Moon is directly in front of you (that is, this time it is transiting your meridian). So, the full Moon transits at midnight.

It is midnight when the moon is at its highest point in the sky looking south. It is 3 a.m. when the moon is half way up the sky between the western horizon and the highest point the moon can get looking south.

It is the Earth's rotation on its axis that makes the moon rise in east and set in the west. The picture below is of the moon setting in the west behind the Sierra Nevada mountains in the morning.

Moonrise (and, incidentally, the time of high tide) occurs about 50 minutes later each day than the day before. To determine the moonrise time for each day of the month, add 50 minutes each day after a phase or subtract 50 minutes each day before a new phase.

In its most general sense, twilight is the period of time before sunrise and after sunset, in which the atmosphere is partially illuminated by the sun, being neither totally dark or completely lit.

What time is it on the moon? Astronauts, set your watches. Time on the surface of the moon has been calculated to tick at a rate of 57 millionths of a second a day faster than it does on Earth, a difference that could be crucial as lunar exploration ramps up.

This shift means Earth has to rotate a little longer to bring the Moon into view, which is why moonrise is about 50 minutes later each day. As it rises at a later time, the Moon appears in a different part of the sky.

The Moon has to make it through an entire loop of the Earth in about 28 days, which means it's moving by about 13 degrees in the sky every day. The Earth, meanwhile, rotates through 15 degrees every hour, in order to rotate 360 degrees every 24 hours.