A Roman astrologer once refused to cast a chart until he knew which quarter of the sky the Moon occupied. He was not being difficult. He was reading a different book than we do. The first quarter moon and the last quarter moon are both half-illuminated, but they are opposite in phase, in timing, and in meaning: the first quarter is a waxing half, the last quarter is a waning half, and they stand at the two crossroads of the lunar month.
The difference is not cosmetic. It is structural. The two halves of the Moon look identical to the naked eye, yet they belong to different halves of the cycle, different energies, and different traditions of practice. One builds. The other releases. Knowing which one hangs in the sky tells you where you are in the month, and what the night is asking of you.
What exactly is a quarter moon?
A quarter moon is the moment when the Moon has completed one quarter or three quarters of its orbit around Earth. The term is astronomical, not visual. At both quarters, we see exactly half of the lunar disk illuminated, because the Sun, Earth, and Moon form a right angle.
The first quarter moon occurs about seven days after the new moon. The Moon has traveled one quarter of its orbit, and the right half of its disk is lit for observers in the Northern Hemisphere. It rises around noon and sets around midnight. The illuminated side faces west, toward the setting Sun.
The last quarter moon, also called the third quarter, occurs about 22 days after the new moon, or seven days after the full moon. The left half of the disk is lit in the Northern Hemisphere. It rises around midnight and sets around noon. The illuminated side faces east, toward the rising Sun.
The names confuse people. The first quarter is not the first time the Moon is a quarter lit. It is the first quarter of the orbit. The last quarter is the third quarter of the orbit, the last one before the cycle closes. Sources disagree on which name is older, but both have been in continuous use in English astronomy since at least the 17th century, when they appear in the almanacs of John Gadbury and Vincent Wing.
Where do the quarter moon names come from?
The names come from the fourfold division of the lunar month, a system older than writing. Babylonian astronomers divided the synodic month, the 29.5 days from new moon to new moon, into four phases. Greek astronomers inherited the scheme. Ptolemy, writing in the second century CE in his Almagest, used the quarters to compute lunar positions for eclipse prediction.
The English terms arrived through medieval Latin. The Venerable Bede, in his 8th century treatise De Temporum Ratione, described the lunar month as divided into four parts, and he gave each part a name in the Anglo-Saxon calendar. The first quarter he called nihtwæcce, the night watch. The last quarter he called bæddæg, the biding day. The names did not survive, but the structure did.
What mattered to Bede and his readers was not the shape of the Moon but its age. The quarter moon told you how many nights had passed since the new moon, and therefore how many nights remained until the next one. That mattered for tides, for planting, and for the dating of Easter, which is still computed as the first Sunday after the first full moon following the vernal equinox.
How the two quarters differ in symbolism
The first quarter moon is a growing thing. It has passed the dark of the new moon and is moving toward fullness. Its light increases each night. In the Western esoteric tradition, this is the phase of building, of intention, of action taken in the world. The seed has been planted at the new moon. At the first quarter, it breaks the soil.
The last quarter moon is a diminishing thing. It has passed the full moon and is moving toward darkness. Its light decreases each night. This is the phase of release, of completion, of letting go. What was built at the first quarter is now harvested, dismantled, or allowed to fall away.
The symbolism is not arbitrary. It follows the visible evidence. A waxing Moon gains light, so it has been associated with increase since antiquity. A waning Moon loses light, so it has been associated with decrease. Plutarch, in his essay On the Face in the Moon’s Orb, written around the first century CE, described the Moon as a place of purification, where souls were cleansed between incarnations. The waning half of the cycle was the cleansing half.
In practical terms, the two quarters ask different things of you. The first quarter asks what you are building. The last quarter asks what you are willing to surrender. One is the phase of effort. The other is the phase of release. They are not opposites in the sense of good and bad. They are opposites in the sense of inhale and exhale.
What each quarter means in practice
The first quarter moon is the phase of obstacles and decisions. In the lunar cycle, it follows the new moon, when intentions are set. At the first quarter, those intentions meet the world, and the world pushes back. This is why the first quarter is traditionally associated with action, with the moment when a plan must be tested.
We light a candle at the first quarter, but not for the intention itself. That was done at the new moon. The first quarter candle is for the work of the week ahead, for the friction of making something real. The flame is the effort. The wax is the time it takes.
The last quarter moon is the phase of release and revision. It follows the full moon, when things are at their peak. At the last quarter, the peak has passed, and what remains is the work of letting go. This is the traditional time for banishing, for cutting ties, for clearing space.
We do not light a candle at the last quarter. We let one burn out. A small dish of salt and water sits on the windowsill overnight, and in the morning it is poured into the ground. The gesture is simple. The salt absorbs. The water carries. The earth takes.
The two quarters also govern different kinds of divination. The first quarter is favorable for questions about beginnings, about what to do next, about the outcome of an undertaking in its early stages. The last quarter is favorable for questions about endings, about what to release, about the lessons of a completed cycle. A reading done at the wrong quarter is not wrong. It is simply reading the wrong page of the month.
First quarter vs last quarter: a direct comparison
The two quarters are mirror images, and the mirror is exact. In the Northern Hemisphere, the first quarter is lit on the right. The last quarter is lit on the left. In the Southern Hemisphere, the illumination is reversed, which is why Australian and New Zealand sources sometimes describe the same phases with opposite sides lit.
The timing is also mirrored. The first quarter rises at noon and sets at midnight. The last quarter rises at midnight and sets at noon. One is a daytime moon, visible in the afternoon sky. The other is a nighttime moon, visible in the hours before dawn.
The first quarter is a waxing phase, moving toward the full moon. The last quarter is a waning phase, moving toward the new moon. One is approaching maximum light. The other is approaching minimum light. In the esoteric tradition, this is the difference between growth and decay, between manifestation and dissolution.
The closest adjacent concept is the gibbous moon, the phase between the quarter and the full or new moon. The waxing gibbous follows the first quarter. The waning gibbous follows the full moon and precedes the last quarter. The gibbous phases are the deep work of the cycle, the long middle stretch. The quarters are the thresholds, the moments of decision.
What people get wrong about quarter moons
The most common error is calling the first quarter a half moon. It is not wrong, but it is imprecise. The Moon is half illuminated at both quarters, but the term half moon does not tell you which half of the cycle you are in. The terms first quarter and last quarter are precise. They tell you where you are in the orbit.
The second error is assuming the first quarter is the first time the Moon is visible. It is not. The crescent moon, visible a day or two after the new moon, is the first visible phase. The first quarter comes a full week later.
The third error is confusing the last quarter with the new moon. Both are dark phases in the sense that the Moon is moving toward darkness, but the last quarter is still half lit. The new moon is not lit at all. The last quarter is the threshold. The new moon is the door.
A fourth error, common in popular astrology, is treating the first quarter as a time of pure positivity and the last quarter as a time of pure negativity. Neither is true. The first quarter is the phase of struggle, when a plan meets resistance. The last quarter is the phase of completion, when a cycle ends cleanly. Both are necessary. Both are useful. One is not better than the other.
FAQ
Is the first quarter moon the same as a half moon? Yes, visually. Both the first and last quarter moons appear half illuminated. The difference is which half of the cycle you are in: the first quarter is waxing, the last quarter is waning.
Can you see the last quarter moon during the day? Yes. The last quarter moon rises around midnight and sets around noon, so it is visible in the morning sky. The first quarter moon rises around noon and sets around midnight, so it is visible in the afternoon and evening.
Which quarter moon is best for banishing? The last quarter moon, because it is a waning phase. Its decreasing light has been associated with release and removal since antiquity. The first quarter, by contrast, is better for building and action.
Why is the last quarter moon sometimes called the third quarter? Because it is the third quarter of the Moon’s orbit, counting from the new moon. The terms are interchangeable. The first quarter is the first quarter of the orbit, and the last quarter is the third.
The two quarters are the hinges of the lunar month. One opens the door to fullness. The other opens the door to darkness. Knowing which one is overhead tells you where you are in the cycle, and what the night is asking of you. If you want to track the phases against your own practice, start with our guide to the lunar cycle. For the symbolism of the Moon itself, see our glossary entry on lunar deities. And when you are ready to work with the phases directly, our guide to moon phase rituals walks through what to do at each threshold. The Moon is not a decoration. It is a calendar, and it is always on time.