Sonia M. Rompoti, MSc, Bsc

Measuring time is important in our era, maybe more than ever! In the past, gauging time used to mean determining whether or not you would survive. For example, if you planted a crop at the incorrect time of year, you wouldn’t have enough food to eat over winter. As timekeeping was a matter of life and death, humans looked to a dependable source: the moon. As a result, a calendar based on moon phases was devised. Although it may not be utilized anymore, it was an important instrument in people’s everyday life for centuries. Yet, its repercussions may still be felt even today.

An overview of a lunar calendar

A moon calendar, often known as a lunar calendar, is a calendar that follows the monthly cycles of the moon’s phases. It is one of the world’s oldest calendars, producing lunar months, often known as synodic months. A lunar month is just the period between two consecutive syzygies, such as new and full moons.

Although solar calendars, which are determined by the sun, have had an impact on the Gregorian Calendar, lunar calendars were also critical; as they aided in determining where each month alternates between 29 and 30 days. Keep in mind that the term month comes from the word moon.

Furthermore, ancient civilizations employed moon phases to assist them to determine the four seasons. Because each season includes three full moons, they knew when to accurately organize important tasks like harvesting and hunting.

The moon calendar is now utilized for rituals rather than a formal business. Easter, Ramadan, Rosh Hashanah, and the Chinese New Year are just a few examples of lunar-based celebrations.

Are you still perplexed about how a lunar calendar works? Read on and it will all make sense.

The number of days between each moon phase

There are 29.53 days between each phase of the moon on average. However, this varies just marginally. Some months have 28 days and some have 30. What’s remarkable is that the moon orbits the Earth in around 27.3 days. It will, however, take 2.2 days to “catch up.” What’s the reason? During the time it takes the Moon to complete one orbit around Earth, it travels approximately 45 million miles around the Sun.

Another question you could have is, when does the first day of the month begin on lunar calendars? It all depends. Lunar calendars, for example, such as the Hebrew and Hirji, began when a lunar crescent was observed. The Hindu calendar began the day after a new or full moon. In addition, lunisolar calendars, such as the Chinese, decided the beginning day of the month based on when an astronomical new moon appeared in a certain time zone.

If this topic interests you, stick around for more information on it during this important moon week!

Origins and Current State of the Moon Calendar

The moon calendar’s genesis

Lunar calendars, as previously said, are among the earliest calendars ever utilized. But do you ever wonder how it all started?

According to the Encyclopedia Britannica, “the Sumerians were probably the first to construct a calendar based wholly on the recurrence of moon phases. Each Sumero-Babylonian month began on the first day of the new Moon’s appearance. Although one intercalary month was employed on a regular basis,” the Britannica article continues, “intercalations were haphazardly introduced when the royal astrologers noticed that the calendar had fallen seriously out of pace with the seasons.” Greek astronomers finally “devised rules for intercalations to synchronise the lunar and solar years.” The Roman republican calendar was most likely based on the Greek lunar calendar.” The Greeks were also the first to notice how the moon impacted everything from tides to agriculture to human conduct. This data was entered into their calendars. By 1582, people had begun to depend more heavily on the Gregorian calendar. However, China did not accept it until 1912, and Russia did not adopt it until 1918, and until then they solely regarded the lunar calendar to be of full power.

But is the lunar calendar still in use, and if yes, where?

The lunar calendar is no longer widely used nowadays. The Gregorian calendar is now used in almost every country on the planet. However, there are certain exceptions. Saudi Arabia, for example, continues to utilize the lunar Islamic calendar.

Moon calendars are mostly used for religious and cultural purposes outside of Saudi Arabia. The lunar calendar is used to commemorate Easter and Chinese New Year. This explains why the dates differ from year to year. Furthermore, Ramadan begins and ends with the first glimpse of the Waxing Moon. This explains why the crescent moon is used as a symbol in many Islamic countries’ flags. The moon is also used to calculate when the Jewish calendar begins in the autumn for Rosh Hashanah, the Jewish New Year. These events are so significant that they are now recognized as legal holidays in most nations.

Important Moon Phases

The lunar calendar’s moon phases

“When it’s there, the moon is the easiest celestial object to spot in the night sky.”

The Lunar calendar contains eight lunar phases. The location of the moon in reference to the sun determines each phase. So, here are the eight moon phases in chronological order:

The New Moon

The first phase is referred to as a new moon. When the moon lies squarely between the Earth and the sun, it is called a new moon, as the moon’s dark side faces the Earth. As a result, the new moon appears totally dark. This is a good time to set our intentions, which are going to be manifested as the moon fills up.

Cresent Waxing

Have you caught a glimpse or a small slice of the silver moon in the sky? This is the start of the Waxing Cresent stage, which starts a couple of days after the new moon stage.

The first quarter

When the moon is 90 degrees between the sun and the Earth, this phase begins. It got its name because the moon had completed a quarter of the full lunar cycle.

Gibbous waxing

As the moon is starting to increase towards full form, Gibbous Waxing stage arrives. This phase technically encompasses the time between the first quarter and full moon phases.

The Full Moon

The moon usually becomes completely lighted two weeks following the new moon. As a result, the moon is now halfway through its orbit.

Some special moons exist during the year:

When the moon is at its closest point to the Earth, it appears as a supermoon.

When the moon is at its furthest distant, it is called a micro-moon.

Finally, a lunar eclipse occurs when the moon passes right through the Earth’s shadow.

Gibbous Moon

Waning implies a decrease after the full moon stage, as it seems smaller a week following a full moon because the amount of moon visible clearly diminishes.

The third quarter

The three-quarters of the moon’s journey are now complete, and it occurs three weeks after a new moon.

Crescent Waning

The Waning Crescent is the penultimate lunar phase in which the moon appears as a sliver in the sky. It begins four weeks after the new moon.

What about the Full Moon?

Aside from the eight moon phases, each full month of the year has its own distinct name, which is mainly associated with specific agriculture phases or even the weather.

The Harvest Moon, for example, comes when the moon is closest to the fall equinox, which is normally around September. Farmers were able to work late harvesting crops sown in the spring and summer due to the sunny weather.

The following is a list of common full moon names, based on the calendar month:

Moon following Yule in January

Snow Moon in February

Sap Moon in March

Grass Moon in April

Planting Moon in May

Honey Moon in June

Thunder Moon in July

Grain Moon in August

Fruit Moon in September (or Harvest Moon)

Hunter’s Moon occurs in October (or Harvest Moon)

Frosty Moon in November

Before Yule, the Moon is all well known December full moon

The moon’s influence on the Earth

Although the moon is just 1/6 the size of our planet, it still has a significant impact on our world. The most notable example is the rise and fall of sea levels, sometimes known as tides. Keeping in mind that the human body is more than 60% water, there is no need to explain how the moon affects us as well.

Furthermore, if Earth did not have a moon, the duration of a day would not be 24 hours. It would just take 8 hours. To put it another way, the Earth would be rotating significantly quicker. That would result in some extremely strong gusts, which could be even lethal for any living organism. It’s no wonder, therefore, that the moon has affected everything from popular culture to calendars.