本文介绍了月球的周期性变化以及当前（8月12日）的月相。月球围绕地球公转，受太阳光照射角度影响，呈现出从新月到满月再到残月的八种不同月相，整个周期约为29.5天。8月12日为盈凸月，月球表面88%被照亮。此外，文章还提及当晚是英仙座流星雨的观测高峰期，并介绍了无需辅助工具即可看到的月面特征（如开普勒环形山）以及使用望远镜可观测到的更多细节（如阿波罗16号着陆点、高加索山脉）。文章还预告了下一次满月日期为9月7日，并详细解释了八种月相的成因与表现。

🌕 月相的形成源于月球围绕地球的公转以及太阳、月球、地球三者相对角度的变化。月球周期约为29.5天，在这个过程中，月球被太阳照亮的部分在地球上呈现出不同的可见形态，从而形成新月、娥眉月、上弦月、盈凸月、满月、亏凸月、下弦月、残月这八种基本月相。

✨ 8月12日，月球正处于盈凸月阶段，大约88%的月面被太阳照亮，在北半球的夜晚，月球右侧（南半球为左侧）会逐渐变暗。这一时期也是英仙座流星雨的观测高峰，尽管月光可能会影响部分流星的可见度，但仍有流星能够穿透月光被看到。

🔭 在无辅助观测条件下，可识别月面上的开普勒环形山、静海和风暴海。若使用望远镜，则能观测到阿波罗16号着陆点、席勒环形山以及绵延323英里（约520公里）的高加索山脉等更精细的地貌特征。

🗓️ 文章指出，上一次满月发生在8月9日，而下一次满月将出现在9月7日。月相的周期性变化为天文学爱好者提供了规律性的观测机会。

The moon is still big and bright in our skies following the full moon, but you'll notice that each night it's a little darker on the right-hand side (left if you're in the Southern Hemisphere). This is because of 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. 

So, what's happening with the moon tonight, Aug. 12?

What is today’s moon phase?

As of Tuesday, Aug. 12, the moon phase is Waning Gibbous, and it is 88% lit up to us on Earth, according to NASA's Daily Moon Observation.

There's a lot to see on the moon tonight, and it's also the start of the peak of the Perseids Meteor Shower. The moonlight may dim some of the meteors, but some should still cut through the light.

Alongside this, with no visual aids on the moon, you can spot the Kepler Crater, Mare Serenitatis, and the Mare Vaporum. Add a telescope and you'll see the Apollo 16, the Schiller Crater, and the Caucasus Mountains, a 323-mile-long mountain range.

When is the next full moon?

The next full moon will be on Sept. 7. The last full moon was on Aug. 9.

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.