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A deep red blood moon during a total lunar eclipse — the Moon bathed in the warm copper glow of Earth's shadow, set against a dark starry sky

Lunar Observing Guide · Blood Moon · Total Lunar Eclipse

Blood Moon: Complete Guide — What Causes It, When to See It, and How to Observe

A blood moon is one of nature's most awe-inspiring celestial events — the full Moon transforming into a deep, coppery red as it passes through Earth's shadow. Unlike solar eclipses, lunar eclipses are completely safe to watch with the naked eye, requiring no special equipment. This guide explains the science behind the blood moon, lists upcoming events, and provides practical tips for observing and photographing total lunar eclipses.

Next eventAugust 28, 2026
Duration~103 min totality
VisibilityAmericas, Europe, Africa
SafetyNo eye protection needed
By Elena Reyes Published: Updated: Reviewed & approved by Juhi Sahni, Senior Editor Editorial Standards
Elena Reyes — Senior Science Editor

Elena Reyes

Senior Science Editor

Covers NASA missions, space science discoveries, and astronomical events for Telescope Advisor. Translates complex astrophysical research into practical insights for backyard observers. Based in the San Francisco Bay Area.

What Is a Blood Moon?

A blood moon is the popular name for a total lunar eclipse — when the Sun, Earth, and Moon align perfectly, with Earth positioned directly between the Sun and the Moon. Instead of going dark, the Moon takes on a deep reddish-brown colour, ranging from bright copper to dark brick-red depending on atmospheric conditions. This striking colour is why the media and the public have embraced the name "blood moon."

The term "blood moon" gained widespread popularity after a 2013–2014 tetrad of four consecutive total lunar eclipses, each visible from parts of North America. While the term is not an official astronomical classification, it has become the most recognisable name for total lunar eclipses in popular culture. Astronomically, the correct term is simply a total lunar eclipse, but the evocative name helps capture public imagination.

Not every full Moon produces a blood moon. Most months, the Moon passes slightly above or below Earth's shadow because its orbit is tilted by about 5 degrees relative to Earth's orbital plane. Total lunar eclipses occur only when the full Moon coincides with the Moon crossing the ecliptic plane — typically two to four times per year somewhere on Earth, though any given location may see a total lunar eclipse only once every two to three years on average.

What Causes the Red Colour?

The blood moon's red colour is caused by a phenomenon called Rayleigh scattering — the same physical process that makes sunsets appear red and the sky appear blue. During a total lunar eclipse, sunlight passing through Earth's atmosphere is filtered: shorter blue wavelengths scatter away, while longer red wavelengths pass through and bend (refract) around the edges of Earth, illuminating the Moon with a warm, reddish glow.

If you imagine standing on the Moon's surface during a total lunar eclipse, you would see Earth blocking the Sun — but the rim of Earth would be ringed with every sunset and sunrise on the planet simultaneously. That ring of reddish light illuminates the lunar surface, creating the blood moon effect. The exact shade of red depends on the amount of dust, clouds, and volcanic aerosols in Earth's atmosphere at the time. After major volcanic eruptions, the Moon can appear exceptionally dark and red. The clear skies following rainfall can produce brighter, more copper-toned eclipses.

Astronomers use the Danjon Scale to classify the brightness and colour of total lunar eclipses from L=0 (very dark, Moon nearly invisible) to L=4 (bright copper-red, with a blueish edge). The August 28, 2026 eclipse is expected to rate L=3 to L=4 under typical atmospheric conditions, making it a vivid and memorable sight.

Upcoming Blood Moons: When Is the Next One?

The next total lunar eclipse visible from North America occurs on August 28, 2026, making this summer the perfect time to prepare for the event. This eclipse will be visible across the Americas, Europe, and Africa, with totality lasting approximately 103 minutes — one of the longer totalities of the decade.

Date Type Totality Duration Visible Regions
August 28, 2026 Total ~103 min Americas, Europe, Africa
February 20, 2027 Total ~89 min Americas, Europe, Africa, Asia
August 17, 2027 Penumbral N/A Asia, Australia, Pacific
January 12, 2028 Partial N/A Americas, Europe, Africa

For the August 28, 2026 eclipse, the Moon will begin entering Earth's penumbra at approximately 1:30 AM EDT (10:30 PM PDT) and totality will begin around 2:45 AM EDT (11:45 PM PDT). The best viewing is from North America, where the eclipse will occur high in the sky during the pre-dawn hours. European observers will see it during the evening twilight, while African viewers will witness it near midnight.

How to Observe a Blood Moon

One of the best things about lunar eclipses is that they require no special equipment or eye protection. Unlike solar eclipses, where you must use certified solar filters, a blood moon is perfectly safe to watch with your naked eyes, binoculars, or a telescope.

With the Naked Eye

Find a dark location away from streetlights with a clear view of the sky. The blood moon is visible across an entire hemisphere, so no specific location planning is needed beyond clear skies. Watch as the Moon gradually darkens, then transforms into its red hue over the course of about an hour. The transition from bright white to deep red is subtle at first, then dramatic as totality approaches.

With Binoculars

10×50 binoculars transform the blood moon experience. The red colour becomes more vivid, and you can see the curved edge of Earth's shadow crossing lunar features in real time. Watch as specific craters (Tycho, Copernicus, Plato) disappear into the shadow one by one. A tripod is helpful for extended viewing but not essential.

With a Telescope

A 4-inch or larger telescope at 50–100× provides a breathtaking close-up. During totality, the Moon's surface takes on a three-dimensional quality as the reddish light creates dramatic shadow effects across the lunar terrain. The craters near the terminator (the edge of Earth's shadow) appear particularly sharp. A 6-inch scope reveals subtle colour variations across the lunar surface during totality — some areas appear more orange while others stay darker. For the best telescope to use, see our Best Telescope for Moon Viewing guide.

How to Photograph a Blood Moon

Photographing a blood moon is surprisingly accessible with modern equipment. A DSLR or mirrorless camera with a telephoto lens (200mm or longer) on a tripod is ideal, but even a modern smartphone held steadily against a tripod mount can capture a recognisable image of the red Moon.

Camera Settings: Use manual mode with ISO 400–1600 (higher ISO during deeper totality), aperture wide open (f/2.8 to f/5.6), and shutter speeds starting at 1/250s for the partially eclipsed Moon down to 1–4 seconds for totality. The key is to bracket exposures — the Moon's brightness drops by a factor of roughly 10,000 from full Moon to total eclipse, so you will need very different settings for each phase.

Composition Tips: Include foreground elements (trees, buildings, mountains) to add scale and interest. Use a wide-angle lens for a "Moonscape" shot that captures the eclipse progression and the surrounding landscape. A time-lapse sequence showing the Moon's colour transition from white through orange to deep red is one of the most rewarding eclipse photography projects. Plan your time-lapse to capture at least one frame every 30 seconds over the 1.5-hour totality window.

Blood Moon Myths and Cultural Significance

Throughout history, blood moons have inspired fear, wonder, and prophecy across virtually every culture. The Inca believed a jaguar was attacking and eating the Moon, and they would shake spears and make as much noise as possible to drive the jaguar away. The ancient Mesopotamians saw lunar eclipses as direct attacks on their king — they would place a substitute king on the throne during the eclipse to absorb any ill fortune.

In Hindu mythology, the demon Rahu is said to swallow the Moon during an eclipse, causing it to turn red. People would fast and bathe in holy rivers to purify themselves during the event. Many Native American tribes also interpreted the blood moon as a time of transformation and spiritual significance, and some still hold ceremonies during lunar eclipses today.

In modern times, the term "blood moon" gained new life through the 2013–2014 lunar eclipse tetrad, which coincided with the Jewish festival of Passover. Some religious interpretations associated the tetrad with biblical prophecy from the Book of Joel: "the sun shall be turned into darkness, and the moon into blood, before the great and the terrible day of the Lord." While astronomers view blood moons as purely natural events, the name has firmly embedded itself in popular culture.

Frequently Asked Questions

What is a blood moon?

A blood moon is the popular name for a total lunar eclipse — when the Sun, Earth, and Moon align, and the Moon takes on a reddish colour from sunlight filtered through Earth's atmosphere.

Is a blood moon dangerous to look at?

No. Unlike solar eclipses, a blood moon is completely safe to view with the naked eye, binoculars, or a telescope. No eye protection of any kind is needed.

When is the next blood moon?

The next total lunar eclipse visible from North America occurs on August 28, 2026, with totality lasting approximately 103 minutes. It will be visible across the Americas, Europe, and Africa.

Why does the Moon turn red during a blood moon?

The red colour is caused by Rayleigh scattering — the same effect that makes sunsets red. Sunlight passing through Earth's atmosphere is filtered, with blue light scattering away and red light bending around Earth to illuminate the Moon.

Do you need a telescope to see a blood moon?

No. A blood moon is visible to the naked eye across an entire hemisphere. Binoculars or a telescope enhance the view, showing the shadow crossing lunar features and more vivid colour.

How long does a blood moon last?

Totality — the period when the Moon is fully within Earth's shadow — lasts between 30 minutes and 107 minutes depending on alignment. The August 28, 2026 eclipse has a totality of approximately 103 minutes.