The second brightest object in the sky after the sun is the moon. Unlike the sun, it is perfectly safe to observe the moon and has fascinated us, humans, for millennium; for this instance, we answer the big question of what are the phases of the moon and in the correct order.
The moon changes its apparent shape over the month as it orbits the earth; this is what is called phases. Our closest celestial partner, the moon, has eight named phases throughout the month. People often want to know the moon phases, and I aim to list them below with more helpful information.
You may have noticed from the list above that there is no “half-moon”; this is due to the term not being astronomical.
As the moon moves into each phase, they are separated by the approximate number of days. We use approximate days because the days can change slightly due to the moon’s elliptical orbit. We have given an illustration below to show how the moon moves. I have also included the approximate day and explained each phase.
Learning the moon phases is crucial for bagging yourself the lunar 100 if you take up the challenge.
The phases are also said to wax on a full moon and wane off to the next new moon.
Waxing Crescent: 0 – 7.4 days
The waxing part of the name means that the moon is starting to illuminate and grow. The crescent part of the name means that the moon is less than half of the moon is illuminated.
At this stage of the moon’s movement, we are viewing the night side of the moon.
First Quarter: 7.4 days
Exactly half of the nearside of the moon is illuminated during the first quarter. Shadows are cast from east to west at this stage, with excellent views available.
The moon is around 90 degrees away from the sun at this stage of its lunar cycle. Also, the moon has moved around a quarter of the way around the earth since the new moon happened.
Waxing Gibbous: 7.4 – 14.8 days
At the waxing gibbous stage, the moon is over 50% illuminated but less than 100%. A phase of the moon that is often just called gibbous.
The term waxing means that the moon is getting bigger; the gibbous part refers to the less than full shape.
Full Moon: 14.8 days
Maybe the stage when it’s most impressive to the naked eye. However, not the best for viewing the moon with a telescope when picking out features. The reason for this is that there very few shadows cast to pick out the surface features.
The moon’s dayside is 100% pointed at the earth’s night side, giving us a view of the full moon down on earth.
Waning Gibbous: 14.8 – 22.2 days
The terminator emerges on the eastern side of the moon and creeps towards what is called the meridian. If you have a telescope, then the waning gibbous phase is when the shadows start to grow on the eastern side, and surface features start to appear.
The waning part of the name means that the moon is getting smaller and the gibbous refers to the shape being less than 100%.
Last Quarter: 22.2 days
Only the moon’s western hemisphere is now available; the last quarter rises early morning and is breathtaking and unmistakable.
The moon from this stage is now leading the sun in its orbit.
Waning Crescent: 22.2 – 29.53 days
Waning refers to the moon getting smaller, and the crescent refers to the shape being a curved shape.
During this stage, it is very hard to observe due to the thin nature. If there is a lot of sunlight, you may find it near impossible to view the moon at this stage. Timing your observing is crucial if you need to find a lunar 100 surface feature.
New Moon: 29.5 – 0 days
The new moon is when the lunar synodic month restarts. The new moon is when the night side of the moon is facing the earth. It can be near impossible at times to see this phase of the moon with the naked eye.
Why does the moon have phases?
Why does the moon change its shape? When people don’t know that the term they are looking for is Phase, they often call it to shape and don’t find an answer.
The reason that the moon has phases is that two different things are happening.
First, when the sun sets and the moon rises, the moon that faces earth when it rises gets the full blast of the sunlight. Second, the moon orbits the earth, which changes the moon’s section to be illuminated by the sun, then this gives us a different portion of the moon we see in our sky.
Learning what the moon phases are will help you nail down the lunar 100. I hope that this article helps you pinpoint the perfect day to find the lunar surface feature.
Over the 29.5 days of a lunar month, there are excellent times for finding surface features and better views. Each side of a full moon is perfect for a telescope view, but a full moon is fantastic if you look at it with the naked eye.
We also learned that the moon is waxing on a full moon and is waning off to the next new moon.