Understanding what the phases of the Moon are that appear in the lunar calendar and why we see the Moon wax and wane each month is exciting, but above all it is being able to look at the sky and capture even a tiny part of the magic that makes everything possible.

Here you will find a complete guide to understand the phases of the Moon and be able to identify them when you look at the night sky.

Phases of the Moon: what they are and why they occur

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If we see light on the Moon it is not because the Moon emits any light, but because sunlight also reaches its surface. The Sun always illuminates half of the Moon, in the same way that it always illuminates half of the Earth, and the illumination on the Moon moves as the Moon rotates on itself and around the Earth.

The different ways in which we see the Moon from Earth, depending on the surface that the Sun is illuminating at any given momentis what we know as phases of the Moon.

The phases of the Moon They depend on the position in which the Sun, Moon and Earth are located. at each moment of the lunar cycle:

• When the Sunlit half of the Moon coincides with the side of the Moon that we see from Earth, we see the Full moon.
• When the Sun illuminates only the side of the Moon that we cannot see from Earth, the side visible to us remains in darkness and the New moon.
• The rest of the timeas the Moon advances in its orbit around the Earth, we see only a portion of the Moon’s illuminated surface. The other part is on the side of the Moon that we cannot see from Earth.

The time between one new Moon and the next is known as lunar cycle or lunation and lasts 29.53 days. During each lunar cycle or lunation, therefore, all the phases of the Moon occur gradually and following an order.

Phases of the Moon: what are they

Although it could be said that there are as many phases of the Moon as there are nights that occur over the years, they have been established four main Moon phases and four intermediate Moon phases based on the percentage of illumination of the Moon’s face that we see from Earth.

The lunar cycle or lunation begins with the new moon phase. and, from there, the others follow one another.

From an astronomical point of view, the main phases of the Moon occur at an exact time which depends on the angle that the Moon and the Sun form with respect to the Earth. They are the Full Moon, the New Moon, the Waning Quarter and the Waxing Quarter. That is why exact times are given for these phases in the lunar calendar.

Instead, the phases of the intermediate Moon They are used to refer to how we see the Moon in the transition days between those main lunar phases. They do not occur at an exact time.

The phase of the Moon is the same in the northern hemisphere and the southern hemisphere. That is, when it is a full moon in the northern hemisphere, it is also full in the southern hemisphere, and the same for the rest of the lunar phases. However, in the quarterfinals and intermediate phases the moon looks differentwith the light directed to one side or the other. It also varies as we approach or move away from the equator.

Therefore, when you look at the lunar calendar of the southern hemisphere, the phases of the Moon coincide (with the exception of minor date variations due to the difference in time zones), but the moons are oriented backwards.

Phases of the Moon explained one by one

New moon or new moon 🌑

The new moon phase occurs in the moment when the Moon, in its orbital movement, is between the Earth and the Sunforming an angle of 180º.

When this happens, the Sun completely illuminates the far side of the Moon, while the side we see from Earth remains completely dark.

In the sky the new moon it is very difficult to seenot only because it is not illuminated by the Sun, but also because it is located in the firmament closest to the Sun. It rises during the day, shortly after dawn, and the Sun is so bright that it prevents us from seeing anything else. It also sets shortly after the Sun sets, so during our night it disappears from the sky.

We can only see the new Moon when a solar eclipse. In fact, solar eclipses always occur during a new Moon, when when the Moon comes between the Earth and the Sun it does so in a perfect or almost perfect alignment and prevents us from seeing the Sun or a part of it.

• New Moon Illumination: 0%
• New Moon Rise: shortly after dawn.
• New Moon Setting: shortly after sunset.

Crescent moon (concave or visible new moon) 🌒

When the visible side of the Moon begins to receive sunlight we enter the crescent Moon phase.

In these first days when the crescent Moon looks very finite, we talk about New moon visible. The concave shape that the Moon draws in this crescent Moon phase makes it also called Concave crescent moon.

In this phase, the Moon looks different in the northern hemisphere and in the southern hemisphere: in the northern hemisphere it draws a «D», while in the southern hemisphere draw a «C».

• Concave Crescent Moon Illumination: from 0.1% to 49.9%
• Moonrise: in the morning.
• Moonset: in the afternoon.

Crescent quarter 🌓

The crescent phase occurs at the exact moment when The Moon makes an angle of 90º with the Sun with respect to the Earth, which is known as square. This position occurs twice throughout the lunar cycle, in the waxing phase and in the waning phase. Since this phase is the first of the lunar cycle in which the square occurs, It is also called «first quarter»«.

Then, we see half of the visible side of the Moon illuminated. What happens is that, of the surface of the Moon illuminated by the Sun, we are only seeing 50%. The other 50% remains on the far side of the Moon.

During the crescent phase, In the northern hemisphere we see the right half illuminated of the Moon; in the southern hemispherelooks illuminated the left half.

• Illumination of the Moon in the first quarter: 50%
• Moonrise: around noon.
• Moonset: around midnight.

Gibbous crescent moon 🌔

Once the crescent phase has passed, from Earth We begin to see the Moon illuminated by more than 50%.

This intermediate lunar phase is known as the gibbous crescent Moon because of the humped shape that the Moon acquires in the firmament, although It is also called «Convex Crescent Moon». It is the lunar phase that takes place between the first quarter and the full Moon.

During this phase of the Moon, we can contemplate the Moon in the sky from the moment it sets, as the Moon rises before the Sun sets.

• Illumination of the gibbous crescent moon: from 50.1% to 99.9%.
• Moonrise: in the afternoon.
• Moonset: at dawn.

Full moon or full moon 🌕

The full moon phase occurs when Moon, Earth and Sun alignas in the new Moon, but this time The Earth is in the middle, forming an angle of 180º between the three.

The visible side of the Moon is completely illuminated and the hidden side is plunged into the darkness of the universe.

The full Moon is the phase of the Moon most anticipated by everyone, not only because of its spectacular nature, but because it is the phase of the Moon that is most present throughout the night: appears over the horizon when the sun sets and remains in the firmament until dawn.

In the full Moon phase we can see the Moon, therefore, throughout the night. It is only hidden when a lunar eclipse. That is why lunar eclipses always occur on a full Moon, when when the Earth comes between the Moon and the Sun it does so in a perfect or almost perfect alignment and prevents us from seeing the Moon or a part of it.

• Illumination during the full moon phase: 100%
• Moonrise: towards the sunset.
• Moonset: towards dawn

gibbous waning moon 🌖

Once the full Moon phase has ended, from Earth We begin to see the Moon still very illuminated but every day a little less.

To this intermediate lunar phase, which takes place between the full moon phase and the last quarter phaseit is known as the crescent gibbous Moon because of the humped shape that the Moon acquires in the firmament, although It is also called the «Convex Waning Moon».

During this phase of the Moon, we can watch the Moon appear in the sky each night a little later, after sunset.

• Illumination of the gibbous crescent Moon: from 99.9% to 50.1%.
• Moonrise: in the afternoon-night.
• Moonset: early in the morning.

Last quarter 🌗

The last quarter phase occurs, like the first quarter, at the moment when The Moon forms a square with the Sun, that is, an angle of 90º. with respect to Earth. Since the Moon has already traveled three quarters of its orbit, at this last quarter phase It is also known as «third quarter».

Then, we see half of the visible side of the Moon illuminated. It is the opposite half to the one we saw illuminated in the crescent phase. In it northern hemisphere it is about the left halfwhile in the southern hemisphere the light is illuminated right half.

• Illumination of the Moon in the last quarter: 50%
• Moonrise: around midnight.
• Moonset: around noon.

Waning moon (or concave waning) 🌘

As sunlight retreats from the near side of the Moon, there comes a time when less than half of the Moon is illuminated. We thus enter the last stretch of the waning phase. It is the intermediate phase that goes from the first quarter to the new Moon.

As the lighting reduces after the last quarter, The Moon draws a more pronounced concave shape every dayand hence this phase is also known as the concave waning phase.

In this phase, the Moon continues to look different in the northern hemisphere and in the southern hemisphere: in the northern hemisphere draw a «C», while on the hemisphere draw a «D».

• Concave Waning Moon Illumination: from 49.9% to 0.1%.
• Moonrise: first thing in the morning.
• Moonset: early afternoon.

To know more about the Moon…