Before we get into what the Last Quarter moon phase is exactly, let’s first look to understand the different phases of the moon in general, and why they occur.
The Moon
With an apparent magnitude of about −2.5 to −12.9, the Moon is the brightest object in our night sky. Still, it is about 400,000 times dimmer than the Sun whose apparent magnitude is −26.74.
Though it looks bright in our sky, the Moon does not produce its own light. It only reflects light from the Sun. Because of that, it is not fully lit up all the time. As it rotates on its axis, one side of it is illuminated by the Sun while the other is in darkness.
In short, as seen from space, half of the Moon’s surface is always illuminated. It has a dayside and a nightside just like Earth.
Phases of the Moon
As the Earth’s orbit brings it around the Sun and the Moon moves around Earth, the objects in our sky are not fixed in place. Sometimes, we see the dayside, at other times, the nightside faces us. Because of this, the Moon’s shape seems to change from time to time.
The apparent change in the shape of the Moon is caused by the moon cycle. Of course, the Moon does not shrink or grow over time. We just see different fractions of it as it moves and is illuminated in different areas. These changes in the Moon’s appearance are called the Moon phases or the lunar phases.
There are eight phases of the Moon. These changes unfold over a 29.5-day period called the lunar month (synodic month).
| Moon Phase | Sunlit Part as Seen on Earth | Average Moonrise and Moonset Times | |
|---|---|---|---|
| New Moon | – 0% illumination | Invisible Phase | 6 am–6 pm |
| 🌒 Waxing Crescent | – 0.1% to 49.9% illumination | Northern Hemisphere: Right side is lit Southern Hemisphere: Left side is lit | 9 am–9 pm |
| 🌓 First Quarter | – 50% illumination | Noon–Midnight | |
| 🌔 Waxing Gibbous | – 50.1% to 99.9% illumination | 3 pm–3 am | |
| 🌕 Full Moon | – 100% illumination | Fully lit | 6 pm–6 am |
| 🌖 Waning Gibbous | – 99.9% to 50.1% illumination | Northern Hemisphere: Left side is lit Southern Hemisphere: Right side is lit | 9 pm–9 am |
| 🌗 Last Quarter | – 50% illumination | Midnight–Noon | |
| 🌘 Waning Crescent | – 49.9% to 0.1% illumination | 3 am–3 pm | |
What Is the Last Quarter Moon?
The Last Quarter Moon is a half-moon. Also called the Third Quarter phase, this is the last primary phase of the Moon. The other primary phases are New Moon, First Quarter, and Full Moon.
We can think of the Last Quarter as the opposite of the First Quarter phase. The difference is that, during the First Quarter, the Moon is waxing. The sunlit part seems thickening as it is on its way to becoming a Full Moon. However, during the Last Quarter, the visible portion is thinning, as it is leading to a New Moon.
A Half Moon
We use the nickname “half-moon” when we see either the First Quarter or the Third Quarter Moon. Let’s see where they fit in the context of the lunar cycle.
Our Moon’s monthly dance starts with a New Moon when the Earth, Moon, and Sun are in a straight line.
With the Moon at the center, one side of it is facing the Earth while the other is facing the Sun. The Sun-facing portion is experiencing daytime while the side that is facing us is bathed in darkness. We cannot see the Moon this time, so we call it the “invisible phase.”
After the New Moon are the waxing phases. During which, the illuminated portion increases. It starts with the Waxing Crescent Moon where we start to see a sliver of the Moon’s disk. It grows until we can see half of it during the First Quarter. If the sunlit part is more than half of the Moon, then it is Waxing Gibbous. It grows even further to become the Full Moon.
Immediately following the Full Moon are the waning phases. This time, the visible portion of the Moon is shrinking. The Waning Gibbous phase takes place right after Full Moon. During this phase, the Moon loses a little of the visible part but we can still see most of it. When half of it is dark and half is illuminated, it is already the Last Quarter.
In the Last Quarter phase, the Sun, Earth, and Moon form a right angle, with the Earth as the vertex. This is a primary phase, which means the three bodies are in the exact position during this time. As the Moon continues to move around Earth in a counterclockwise direction, it will reach the last stage—the Waning Crescent phase.
It will continue to shrink until we cannot see it anymore. By the time it becomes invisible, the New Moon will signal the start of a new lunar cycle.
When Does The Last Quarter Moon Occur?
The Last Quarter Moon occurs after the Waning Gibbous Moon. Half of the Moon seems illuminated this time, as seen from our vantage point on Earth. It is the last primary phase of the Moon. Overall, it is second to the last, among the eight phases.
Since it is a waning phase, our natural satellite continues to shrink. The Last Quarter phase occurs before the Waning Crescent Moon, the last phase.
Which Side of the Moon Is Visible?
It is easy to identify the Last Quarter Moon in our sky because of its Half Moon appearance. However, the side of the Moon that is lit up looks different from different locations on Earth. Perspective is responsible for this, and not because the Moon changes from time to time.
The illuminated portion of the Moon is the same no matter where we are. However, since we see it from different angles, our location plays a role when it comes to which part of it looks illuminated.
From the Northern Hemisphere, the left half of the Moon is visible during the Last Quarter. It is reversed in the Southern Hemisphere where the right half is visible. Near the equator, observers will see either the upper or lower half of the Moon lit up.
The sides switch up during the First Quarter phase.
| Observers’ Location | First Quarter (and other waxing phases) | Third Quarter (and other waning phases) |
|---|---|---|
| Northern Hemisphere | Right half | Left half |
| Southern Hemisphere | Left half | Right Half |
| Equator | Upper half (after moonrise) Lower half (before moonset) | Lower half (after moonrise) Upper half (before moonset) |
Moonrise and Moonset Times During the Last Quarter
All celestial objects seem to rise and set on the horizon. That includes the Moon, Sun, planets, stars, and other objects that we see in the sky. Of course, these objects do not really set and rise, they just move in their respective orbits at different speeds.
The Sun, for example, takes around 27 days to rotate on its axis. It orbits the center of the Milky Way galaxy in about 250 million years. As with the Moon, it is tidally locked to Earth. That means, its rotational and orbital periods are the same. As a result, only one side of the Moon is facing us. It takes the Moon 27.3 hours to rotate and orbit Earth (sidereal month).
All these different objects move at different rates. However, they all seem to move across our sky in a day. The reason for this is the Earth’s rotation. It moves on its axis in a counterclockwise direction, that is, from west to east. Because of that, the objects in the sky seem to rise from the east and set in the west.
The rising and setting of the Moon become more and more lately as it progresses in its cycle. During the Last Quarter, it rises at midnight and sets when the Sun is at its highest, at noon. It is opposite the First Quarter Moon which rises at noon and sets at around midnight.
The Daytime Moon
Have you ever wondered why we see sometimes see the Moon during the daytime?
The Moon is actually up in the daytime sky for about half of the lunar cycle. However, seeing it can sometimes be a challenge when it is close to the Sun. Since the Sun is much brighter, its glare will make any other objects invisible.
Still, knowing about the phases will give us an idea of when to see the daytime Moon best. It will tell us when it will rise and set, and whether it will be close to the Sun in the sky.
During the New Moon, for example, the Moon rises with the Sun at around 6 am and sets at about 6 pm. Though it is up in the morning, we cannot see it because the Sun is way much brighter. At Full Moon, it rises at 6 pm and sets at 6 am so it is not up during the daytime.
The Best Time to see the Moon in Daytime
The best time to spot the daytime Moon is during the Last Quarter and the First Quarter. During these periods, the Sun and Moon are not together nor in opposite directions in the sky.
In the Last Quarter, the moonrise is around midnight. It will be at its highest point in the sky when the Sun rises at around 6 am. That means, it is visible the whole morning, before it dips below the horizon at noon.
The opposite happens during the First Quarter phase when the Moon rises at noon. We can still see it in daylight as it is visible the whole afternoon. It is at its highest point at around sunset, before setting at around midnight.
Stargazing Under the Last Quarter Moon
As we know, the Moon is the brightest object in the night sky. Because of that, it can affect how well we can observe the other fainter celestial bodies. Still, the different phases of the Moon present many opportunities for astronomical observations.
The Moon phases have different advantages depending on the object you are trying to observe. If you want to observe the Moon at its most spectacular state, then it is best to observe it during the Full Moon.
Most people camp out and set up their telescopes to observe more unique objects. From stars to planets, to galaxies and nebulae, we can spot a lot of gems up above. However, these objects are much more distant than the Moon so we need a dark sky to see them. With that said, the best time to spot them is during a New Moon.
Even so, even if the sky is not at its darkest during the Last Quarter phase, it is still a good time for stargazing. Since it is a Half-Moon, the night sky has just the right brightness during this phase. It is not as dark as the New Moon, but also not as luminous as the Full Moon.
We can still enjoy observing some celestial objects during the Last Quarter. We can maximize this by choosing a spot away from light pollution. In fact, the period between the Last Quarter up to the First Quarter of the next cycle is ideal for these observations.
Effect on the Sea and Tides—Neap Tides
The position of the Sun and Moon relative to Earth has great effects on tides. The Sun and Moon’s gravitational pull causes the change in our seas and oceans. With that in mind, the different phases of the Moon tell us about these tide changes.
With the Sun and Moon on the opposite sides of the Earth, their pull of gravity is combined. That means, during the New Moon and Full Moon, the changes in tides are at their maximum. We call this the “spring tide.” It means that high tides are exceptionally high and the low tides are also very low.
The opposite happens during the quarter phases, when the Sun, Earth, and Moon are at a right angle. In this position, the Sun and the Moon are exerting their influence on Earth from two different directions. Because of that, gravity from both bodies is canceled out. This results in what we call the “neap tides.”
Though the Sun is much bigger, the gravitational pull of the Moon has a bigger impact because it is much closer to us. So, even if the pull is canceled during the quarter phases, we still get small changes in tides because of the Moon.
Neap tides are the opposite of spring tides. It is when the high tides are relatively lower and the low tides are relatively higher. In short, we get moderate tides during this time. That said, there is a little difference between high tides and low tides on the Last Quarter phase of the Moon.
Interesting Moon Facts
- The dividing line on the dayside and nightside of the Moon is called the “terminator.”
- The side of the Moon that is facing us is called the near side. The other part of the Moon that is facing away from Earth is called the far side. There is no “dark side” because both sides receive sunlight during different phases.
- The Moon orbits the Earth in 27.3 days. We call this a sidereal month. A lunar month or a synodic month lasts 29.5 days. This is when the Moon completes a lunar cycle, from one New Moon to the next.
- Sunsets can help in identifying whether the Moon is waxing or waning. If you can see the Moon at sunset, then it is waxing. If you cannot spot it during this time, then it is waning.
Frequently Asked Questions
What happens during the Last Quarter Moon phase?
At the Last Quarter phase of the Moon, the Sun, Earth, and Moon are at a right angle. This results in neap tides or average tide changes.
This primary phase is an exact position of the Moon, when it is only a quarter away from completing the lunar cycle. From our perspective here on Earth, we can see a half-moon.
What is the difference between the First Quarter and the Last Quarter Moon phases?
We can see a “Half Moon” during the First Quarter and the Last Quarter. However, the First Quarter is a waxing phase, which means the visible portion of the Moon is increasing. During the Last Quarter phase, it is waning or shrinking.
Also, the word “quarter” here has something to do with its position in its orbit around Earth.
At the First Quarter phase, the Moon has traveled a quarter into its orbit. It is halfway through this path at Full Moon. Around the Last Quarter, it is only a quarter away from making a full circle around Earth. And when it does, it will be a New Moon.
Is there an eclipse during the Last Quarter phase?
There is no eclipse during the Last Quarter phase. Eclipses happen when one object casts a shadow on another. This means that it only occurs when the Sun, Earth, and Moon are in a line.
Eclipses only take place during two phases: New Moon and Full Moon.
A solar eclipse happens when the Moon’s shadow falls on Earth. During a Full Moon, the Earth blocks direct sunlight from reaching the Moon. As a result, the Earth’s shadow falls into the Moon and causes a lunar eclipse. Still, there is no eclipse every month because the Moon’s orbit is titled by 5 degrees.
Does the moon orbit clockwise or counterclockwise?
The Moon revolves in a counterclockwise direction. That means it moves around Earth in a west to east direction.
Sources:
https://www.open.edu/openlearn/ocw/mod/oucontent/view.php?id=69107§ion=3.12
https://www.timeanddate.com/astronomy/moon/third-quarter.html
https://www.timeanddate.com/moon/phases/@z-us-10001?year=2022
https://moon.nasa.gov/moon-in-motion/moon-phases/
Image Sources:
The Moon: https://theplanets.org/wp-content/uploads/2014/09/moon.png
Last Quarter Moon: https://moon.nasa.gov/internal_resources/362
Phases of the Moon: https://storage.needpix.com/rsynced_images/phases-of-the-moon-150852_1280.png
Which Side of the Last Quarter Moon Is Visible: https://storage.needpix.com/rsynced_images/moon-588471_1280.jpg
Moonrise and moonset: https://storage.needpix.com/rsynced_images/moon-382384_1280.jpg
Daytime Moon: https://storage.needpix.com/rsynced_images/moon-204778_1280.jpg
Stargazing Under the Last Quarter Moon: https://storage.needpix.com/rsynced_images/nature-2576045_1280.jpg
Effect on the Sea and Tides: https://storage.needpix.com/rsynced_images/seychelles-1219564_1280.jpg