文章介绍了月球的29.5天周期性变化，即月相。当前（9月8日）正值亏凸月，月球可见度为99%。文章详细列出了裸眼、双筒望远镜和望远镜可观测到的月球表面特征，并预告了下一次满月将在10月6日出现。此外，文章还解释了月相形成的原理，即太阳、月球和地球相对位置的变化导致月球被照亮的部分不同，并详细描述了新月、峨眉月、上弦月、盈凸月、满月、亏凸月、下弦月、残月这八种主要的月相。

🌕 **月相周期与当前状况**：月球的可见度变化构成了一个约29.5天的周期，称为月相。文章发布时（9月8日），月相为亏凸月，约99%的月面被照亮，这意味着满月已过，月光将逐渐减少直至新月。

🔭 **月球表面观测细节**：文章提供了不同观测设备的月面观测建议。仅凭肉眼可见阿基米德山脉、第谷环形山和静海。使用双筒望远镜可进一步看到亚平宁山脉、阿基米德环形山和阿尔卑斯山脉。若使用望远镜，则能观测到阿波罗12号着陆点、海吉努斯沟和高加索山脉。

🗓️ **未来月相预告与原理阐释**：下一次满月将在10月6日出现。月相变化是由于月球绕地球公转导致太阳、月球和地球之间角度不断变化，从而改变了月球被太阳照亮并从地球上可见的部分。文章详细介绍了新月、峨眉月、上弦月、盈凸月、满月、亏凸月、下弦月、残月这八种月相的形成和外观特征。

The Full Moon has passed, which means each night until the New Moon, we'll see less and less moon each night. This happens as we progress through the lunar cycle.

The lunar cycle is a series of eight unique phases of the moon's visibility. The whole cycle takes about 29.5 days, according to NASA, and these different phases happen as the Sun lights up different parts of the moon whilst it orbits Earth. 

Let's find out what's happening with the moon tonight, Sept. 8.

What is today’s moon phase?

As of Monday, Sept. 8, the moon phase is Waning Gibbous, and it is 99% lit up to us on Earth, according to NASA's Daily Moon Observation.

There's still lots of moon to see, so if you have a cloudless sky, here's what you'll be able to see when you look up. With just the naked eye, enjoy a glimpse of the Aristarchus Plateau, the Tycho Crater, and the Mare Tranquillitatis.

If you have binoculars, you'll also see the Apennine Mountains, Archimedes Crater, and the Alps Mountains. If you're lucky enough to have a telescope, point it upwards to see the Apollo 12 landing spot, the Rima Hyginus, and the Caucasus Mountains.

When is the next full moon?

The next full moon will be on Oct. 6.

What are moon phases?

According to NASA, moon phases are caused by the 29.5-day cycle of the moon’s orbit, which changes the angles between the Sun, Moon, and Earth. Moon phases are how the moon looks from Earth as it goes around us. We always see the same side of the moon, but how much of it is lit up by the Sun changes depending on where it is in its orbit. This is how we get full moons, half moons, and moons that appear completely invisible. There are eight main moon phases, and they follow a repeating cycle:

New Moon - The moon is between Earth and the sun, so the side we see is dark (in other words, it's invisible to the eye).

Waxing Crescent - A small sliver of light appears on the right side (Northern Hemisphere).

First Quarter - Half of the moon is lit on the right side. It looks like a half-moon.

Waxing Gibbous - More than half is lit up, but it’s not quite full yet.

Full Moon - The whole face of the moon is illuminated and fully visible.

Waning Gibbous - The moon starts losing light on the right side.

Last Quarter (or Third Quarter) - Another half-moon, but now the left side is lit.

Waning Crescent - A thin sliver of light remains on the left side before going dark again.