This evening signifies the First Quarter lunar phase, indicating that approximately half of the moon is observable.

The moon experiences eight unique phases, referred to as lunar phases. NASA clarifies that these phases take place as the Sun illuminates various sections of the moon during its orbit around Earth.

Continue reading to find out what celestial sights await you tonight, Sept. 29.

What is the phase of the moon today?

On Monday, Sept. 29, the moon is in its First Quarter phase, and as per NASA’s Daily Moon Observation, 46% of its surface is lit up this evening.

Even without tools, you can spot features such as the Mare Crisium, Mare Tranquillitatis, and Mare Vaporum. Using binoculars will provide great views of the moon’s Apennine and Alps mountain ranges. A telescope will uncover the landing sites of Apollo 17 and 16 along with the Caucasus Mountains.

When will the next full moon be?

The upcoming full moon is set to happen on Oct. 6. The previous full moon occurred on Sept. 7.

What defines moon phases?

According to NASA, the phases of the moon are connected to its 29.5-day path around Earth. As the moon progresses, the angles between the Sun, Moon, and Earth shift, forming the phases we see. The moon may sometimes look full or be entirely obscured, yet we consistently view the same side. The variation lies in the sunlight that reflects off its surface, influenced by its position in orbit.

This results in full moons, half moons, and moons that are not visible. There are eight principal moon phases in a cyclical pattern:

New Moon – The moon is positioned between Earth and the sun, causing the visible side to be dark (not visible).

Waxing Crescent – A small segment of light becomes visible on the right side (in the Northern Hemisphere).

First Quarter – Half of the moon is illuminated on the right side, appearing as a half-moon.

Waxing Gibbous – More than half of the surface is lit, but it is not fully illuminated yet.

Full Moon – The entire face of the moon is lit and can be seen.

Waning Gibbous – The moon begins to lose light on the right side.

Last Quarter (or Third Quarter) – Another half-moon phase, but with the left side illuminated.

Waning Crescent – A thin slice of light persists on the left side before it becomes dark again.