文章介绍了月球的周期性外观变化，即月相。当前正值农历十八，月相为“盈凸月”，即87%的月面被照亮。文章还列举了肉眼可见的月面特征，如哥白尼环形山、静海等，并建议使用望远镜可观测更多细节。此外，文章解释了月相形成的原因是太阳、月球和地球之间角度的变化，以及月球围绕地球公转所形成的29.5天周期。文章最后详细列举了新月、娥眉月、上弦月、盈凸月、满月、亏凸月、下弦月、残月八种主要月相的特征。

🌕 **月相的形成与周期**：月相是由于月球围绕地球公转，导致太阳、月球和地球三者相对位置不断变化，从而我们看到的月球被太阳照亮的部分随之改变。整个月球周期约为29.5天，每个月都会经历一个完整的月相变化过程。

🔭 **月球观测的可见特征**：即使在没有视觉辅助的情况下，也能肉眼看到月球表面的显著地貌，例如哥白尼环形山、静海和第谷环形山。使用双筒望远镜或更高级的天文望远镜，则能观测到更多精细的特征，如更远的环形山和月球上的特定着陆点，极大地丰富了观测体验。

💡 **八大基本月相详解**：文章详细介绍了月球的八种基本月相：新月（不可见）、娥眉月（右侧 sliver 亮）、上弦月（右侧半圆亮）、盈凸月（超过半圆亮）、满月（全圆亮）、亏凸月（右侧开始变暗）、下弦月（左侧半圆亮）、残月（左侧 sliver 亮）。理解这些月相有助于我们更好地把握月球的运行规律。

We're moving towards to the New Moon, which means for the next few nights the moon is going to look smaller and smaller to us. This is normal as we work though the lunar cycle, and we're currently on day 18.

What is today’s moon phase?

As of Saturday, Nov. 8, the moon phase is Waning Gibbous. This means 87% of the moon is lit up tonight, according to NASA's Daily Moon Observation.

No visual aids? No problem, there's still lots for you to see tonight, like the Copernicus Crater, the Mare Tranquillitatis, and the Tycho Crater. A pair of binoculars will let you see even more, including Gassendi Crater, Clavius Crater, and the Alphonsus Crater. If you’ve got a telescope handy, it’s worth using to check out Reiner Gamma, the Apollo 17 landing site, and the Fra Mauro Highlands.

When is the next full moon?

The next full moon will be on Dec. 4.

What are moon phases?

NASA notes that as the Moon orbits Earth over about 29.5 days, it goes through a series of phases. These phases occur because of the changing angles between the Sun, Moon, and Earth. Depending on its position, the Moon can appear fully illuminated, partly illuminated, or completely hidden, even though we always see the same side. What changes is how much sunlight reflects off its surface, creating a repeating sequence known as the lunar cycle.

The eight main moon phases are:

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. (Northern Hemisphere)

Third Quarter (or Last 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.