On September 7, 2025, the sky will host one of the year’s most anticipated astronomical events: a total lunar eclipse lasting 82 minutes, the longest of 2025. Known as a “blood moon” due to its reddish hue, the phenomenon occurs when Earth aligns between the Sun and the Moon, casting its shadow on the lunar surface. Although not directly visible in Brazil, the event can be followed through live streams on platforms like YouTube. It will be most visible in regions such as Europe, Africa, eastern Australia, and New Zealand, captivating astronomers and enthusiasts alike. The red hue results from sunlight filtered by Earth’s atmosphere, creating a unique visual spectacle. This will be the second lunar eclipse of the year, following one in March, and is set to capture the imagination of millions worldwide.
The astronomical event will begin at 15:28 GMT (12:28 Brasília time) and extend until 20:55 GMT (17:55 Brasília time). The totality phase, when the Moon is fully immersed in the umbra, Earth’s darkest shadow, will occur between 17:30 and 18:52 GMT (14:30 to 15:52 Brasília time). During these 82 minutes, the Moon will display its characteristic reddish hue, caused by the refraction of sunlight through Earth’s atmosphere.
- Total duration: 5 hours and 27 minutes, with 82 minutes of totality.
- Visibility: Europe, Africa, eastern Australia, and New Zealand.
- How to watch in Brazil: Live streams on digital platforms.
- Next eclipse in Brazil: March 2026, visible in the Americas.
The phenomenon, known as a blood moon, is one of the most fascinating events in the astronomical calendar, blending science and natural beauty.
What makes the September eclipse unique
The total lunar eclipse on September 7 and 8, 2025, stands out for its exceptional duration, the longest since 2022. The 82-minute totality will allow observers in privileged regions to witness the Moon’s gradual transformation from a silvery glow to a deep red hue. This phenomenon occurs because sunlight, passing through Earth’s atmosphere, has its shorter wavelengths, like blue and purple, scattered, while longer wavelengths, like red, reach the lunar surface.
The Moon’s position, just 2.7 days from perigee (its closest point to Earth in its elliptical orbit), also enhances the spectacle. This will make the Moon appear slightly larger in the sky, amplifying the visual impact. The eclipse will be particularly deep, with 36% of the lunar diameter within the umbra, potentially resulting in a darker, more dramatic coloration.
- Eclipse depth: 36% of the lunar diameter in the umbra.
- Perigee proximity: Moon will appear larger and brighter.
- Color variations: Depend on atmospheric dust and pollution.
The event will be a unique opportunity for amateur and professional astronomers to study Earth’s atmospheric conditions, as the Moon’s hue may reflect particles like volcanic dust.
How the phenomenon occurs
A total lunar eclipse happens when the Sun, Earth, and Moon align perfectly, with Earth blocking direct sunlight from reaching the Moon. This alignment causes Earth’s shadow, composed of the penumbra (outer, lighter part) and umbra (inner, darker part), to cover the lunar surface. The process unfolds in five distinct phases, each with unique visual characteristics.
Initially, the Moon enters the penumbra, experiencing a subtle darkening that is barely noticeable. In the partial phase, the umbra begins to cover part of the Moon, creating a striking contrast. During totality, the Moon is fully immersed in the umbra, displaying the reddish hue that gives the event its blood moon name. After totality, the Moon gradually exits the umbra, returning to the penumbra, until the eclipse ends with the Moon fully clear of Earth’s shadow.
- Eclipse phases: Penumbral, partial, totality, partial, penumbral.
- Totality duration: 82 minutes, from 14:30 to 15:52 (Brasília time).
- Ideal visibility: Start observing 75 minutes before totality.
The reddish hue results from sunlight refracted by Earth’s atmosphere, filtering out shorter wavelengths and allowing red ones to reach the Moon.
Where and how to follow the event
Although Brazil is not in the direct visibility area for the September eclipse, Brazilians can follow the event through live streams. Platforms like YouTube and astronomy-focused websites, such as Time and Date, will offer real-time coverage. For those in visible regions like Europe and Africa, the eclipse can be observed with the naked eye, though binoculars or telescopes can enhance the experience.
In cities like Perth, Australia, the eclipse will occur between 1:30 and 2:52 local time, while in Cairo, Egypt, it will be visible from 20:30 to 21:52 EEST. Observers should seek locations with low light pollution and clear skies for the best experience.
- Visibility locations: Europe, Africa, eastern Australia, New Zealand.
- Perth timings: 1:30 to 2:52, September 8.
- Observation tips: Dark locations with clear horizon views.
- Brazil alternative: Live streams on digital platforms.
The recommendation is to start observing about 75 minutes before totality to witness all phases, from the initial darkening to the event’s peak.
Curiosities about the blood moon
The blood moon has long sparked fascination and stories across centuries. In various cultures, the phenomenon was seen as an omen or supernatural event. Today, science explains the red hue, but its visual impact continues to captivate people worldwide. The September 2025 eclipse will be particularly special due to its extended duration and the Moon’s proximity to perigee.
Another intriguing aspect is the chance to observe stars and constellations more clearly during totality, as the Moon’s brightness diminishes. In some regions, like eastern Australia, the Moon will be positioned in constellations like Leo, near bright stars like Regulus.
- Cultural significance: Eclipses were once viewed as omens.
- Star visibility: More prominent during totality.
- Moon’s position: In Leo, near the star Regulus.
- Atmospheric influence: Dust can intensify the red hue.
The phenomenon also offers a chance to reflect on the dynamics of the solar system and the precision of celestial movements.
Scientific importance of the eclipse
Beyond its visual appeal, the September 2025 lunar eclipse holds scientific significance. Astronomers will use the event to study Earth’s atmosphere, as the Moon’s hue reflects atmospheric conditions, such as the presence of volcanic dust or pollutants. The eclipse’s depth, with 36% of the lunar diameter in the umbra, will also allow detailed analyses of sunlight’s interaction with the atmosphere.
The event is part of a series of lunar eclipses occurring every 18 years and 11 days, known as the Saros cycle. This eclipse belongs to series 123, which includes 72 events, with the next major one in the series expected in 2043.
- Saros cycle: Repeats every 18 years and 11 days.
- Atmospheric studies: Hue reflects dust and pollution.
- Next series eclipse: Expected in 2043.
Observing the eclipse may also inspire new studies on lunar orbits and solar system dynamics, reinforcing the importance of astronomical events for science.