A Night of Light and Shadow: March’s Total Lunar Eclipse

Lunar eclipses are special occasions when light and shadow combine to provide a display that is both memorable and unique. Of the three varieties of lunar eclipses — penumbral, partial, and total — the latter is the one that always gets noticed. On average, a total eclipse of the moon can be seen every two-and-a-half years wherever you live. The last time a total lunar eclipse was visible in this part of the world was March 14, 2025. The next opportunity to see a total eclipse of the moon is coming very soon — on March 3, 2026!

This illustration shows the stages of the eclipse, which will be visible above the western horizon. The eclipse will begin at 3:49 am, when the first hint of Earth’s dark, umbral shadow will begin to appear at the upper left corner of the moon. The total phase of this eclipse will last from 5:04 am to 6:04 am, with mid-eclipse (the most dramatic moment of the event) occurring at 5:34 am. Thereafter, the moon’s familiar whitish color will gradually return as the moon exits the umbral shadow. The moon sets at 6:51 am, preventing observers from seeing the last 26 minutes of this lunar eclipse. Image credit: Rod Nerdahl

The illustration above shows key moments during the eclipse. The first notch caused by Earth’s umbra will appear at 3:49 am. This eclipse is a “night owl” event, but it is one you may want to see nevertheless! Totality will begin at 5:04 am and continue through 6:04 am. Mid-eclipse, when the view is most dramatic, will occur at 5:34 am. After totality ends, the full moon will slowly “reappear,” setting at 6:51 am, 26 minutes before the eclipse show ends.

So, what can we expect to see during the total lunar eclipse on the morning of Tuesday, March 3? There’s plenty to watch and it is worth remembering that eyes and binoculars are the best tools for observing a lunar eclipse.

Eclipses come in two varieties: solar and lunar. Solar eclipses occur when the moon casts its shadow on the Earth. Solar eclipses are only visible during daytime. They can only be observed safely with care — to prevent eye damage. Lunar eclipses occur when the Earth’s shadow falls on the moon and therefore, can only be seen at night. Unlike solar eclipses, an eclipse of the moon can always be observed safely; eye protection is not necessary.

Lunar eclipses happen when the moon passes through Earth’s shadow. Our planet’s shadow has two components: a larger, outer region in which some sunlight is able to reach. This shadow is called the “penumbra.” There is also a smaller, inner shadow called the “umbra.” The only light that can enter the umbra comes from sunlight filtered through our planet’s atmosphere. This means that the light present in Earth’s umbral shadow actually comes from sunlight transmitted into it by all of the sunsets and sunrises occurring at the time the eclipse happens! Thus, the umbral shadow displays the rich red, orange, and yellow hues we see after sunset or before sunrise onto the moon. The light in the umbral shadow is much fainter than full sunlight or the dimmer light that exists in Earth’s penumbral shadow.

A total eclipse of the moon can only occur when the Sun, Earth and moon lie in a straight line with respect to each other in space. At such times, the moon, travelling in its orbit around Earth, enters our planet’s shadow. A total eclipse of the moon can only occur when the moon passes completely through the dark, umbral shadow of Earth. Image Credit: Martin Kornmesser – ESA/Hubble, NASA, and ESA

Lunar eclipses can only take place when the moon appears in the direction opposite the Sun. This happens when the moon is at “full” phase. The Earth’s umbral shadow is about 6,045 miles wide (at the moon’s average distance from the Earth). The penumbral shadow is even larger, 10,365 miles wide. Both of these shadows are quite large: three times wider than the moon for the umbral shadow and five times the moon’s diameter for the penumbra.

So, why don’t we see eclipses of moon every time there is a full moon?

The moon travels in an orbit that is tipped five degrees with respect to the path the Earth follows in its orbit around the Sun. As a result, the moon passes above or below Earth’s shadow most of the time. In a typical year, the moon only passes through Earth’s shadow twice, when the orbital planes of the Earth and moon intersect. These times are called “eclipse seasons.”

A typical eclipse season lasts about 35 days. At these times, the moon, Earth and Sun are aligned, making it possible for the moon to pass through one or both of the Earth’s shadows. Then for a few hours, the lucky inhabitants of Earth who happen to be on the planet’s nighttime side, are privileged to witness a lunar eclipse. If the moon enters the penumbral shadow, the eclipse is a “penumbral” one. Because a great deal of sunlight reaches this outer part of Earth’s shadow, most observers don’t see much change in the moon’s appearance during a penumbral eclipse of the moon. 36% of all lunar eclipses are of the “penumbral” variety. Because there is so little to see when a penumbral lunar eclipse occurs, they often go unnoticed.

When the moon’s path takes it through the penumbra and part of the way into the umbral shadow, some portion of the moon will darken noticeably. The result is a “partial” lunar eclipse. “Partial” eclipses make up 35% of the total number of lunar eclipses. They tend to get more notice and therefore, are more frequently observed. On those occasions when the moon travels through the penumbra and also completely enters the Earth’s umbral shadow, the eclipse is said to be “total.” 29% of all lunar eclipses belong to this category. They are very dramatic and are seldom, if ever, ignored!

People often ask, when will I see another lunar eclipse like this one? The answer is really “never.” Celestial events are not programmed like television reruns. Each lunar eclipse is unique. The dynamics of the Sun – Earth – Moon system changes the orientation of Earth – Moon interaction from one eclipse season to the next. Our planet’s atmosphere also contributes to the eclipse show, adding some singular pizzazz to the event. The amount and distribution of clouds and the presence or absence of dust from volcanic eruptions and forest fires defines the degree of darkness and color seen during lunar eclipses. Taken together,
all of these variables make each lunar eclipse a one-of-a-kind display!

This photo shows the progress of a total lunar eclipse that occurred on September 27, 2015. The images of the moon were taken at 33⅓ minute intervals between 8:07 pm (the start of the eclipse) through 11:27 pm (the end of the event). Image credit: Rod Nerdahl

If you want to know when the next total lunar eclipse will be visible here, the answer is June 25, 2029. Unlike the March 3 event, in which we will miss part of the outgoing phases of the total lunar eclipse, we will miss part of the ingoing phases of the June 25, 2029 eclipse. Totality will begin 34 minutes after the moon rises! If you want to watch a total lunar eclipse from start to finish, you’ll have to wait until January 11, 2047! Maybe the March 3, 2026 total lunar eclipse is worth losing a little shut eye for — it might even be worth waking the kids up for a quick look at the totally eclipsed moon at 5:34 am!

Information and Illustration prepared by Rod Nerdahl, Bell Museum Astronomy Program Volunteer