As we enter the fourth day of the lunar cycle, the Moon is gaining illumination. Keep reading to find out what you can see tonight.

What is the Moon phase today?

As of Tuesday, April 21, the Moon phase is Waxing Crescent. Tonight, 20% of the Moon will be lit, according to NASA’s Daily Moon Guide.

With the unaided eye, you should be able to spot the Mares Crisium and Fecunditatis. If you have binoculars or a telescope, you can also observe the Endymion Crater.

When will the next Full Moon occur?

The next Full Moon is anticipated on May 1, the first of two in May.

What constitutes Moon phases?

NASA indicates that the Moon completes a full orbit around Earth in approximately 29.5 days, transitioning through eight stages. Although the same hemisphere of the Moon always faces Earth, the area lit by the Sun alters as it progresses along its orbit, resulting in the cycle of full, half, and crescent shapes. These variations are known as lunar phases, totaling eight:

New Moon – The Moon is positioned between Earth and the sun, rendering the side we view dark (invisible to sight).

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

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

Waxing Gibbous – More than half is lit, yet not fully illuminated.

Full Moon – The entire surface of the Moon is brightly lit and entirely visible.

Waning Gibbous – The Moon starts to lose light on the right side. (Northern Hemisphere)

Third Quarter (or Last Quarter) – Another half-Moon, but now the left side is illuminated.

Waning Crescent – A slender sliver of light lingers on the left side prior to going dark again.