Key Takeaways on the Seven Sisters Eclipse
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The Seven Sisters Eclipse occurs when the moon in its waning crescent phase moves across the Pleiades and blocks the stars from view.
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The event is not rare and has taken place every month since September 2023. The July 2025 event will occur on July 20 in the early hours of the day.
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The Pleiades contain more than a thousand young stars bound together by gravity, the brightest of which can be viewed with the naked eye
On July 20, 2025, stargazers across much of the U.S. and Canada will be able watch as the moon in its waning crescent phase moves across the Pleiades (or Seven Sisters), temporarily obstructing the stars from view.
The event will occur in the early hours and to witness the moon in action, one can look towards the eastern horizon, ensure a clear line of sight, and avoid bright lights as much as possible.
“No telescope or binoculars will be needed, and the darker your viewing location (the fewer city lights around you) the better your view will be, though both objects can be seen even from bright cities,” says Anna Gammon-Ross, astronomer at the Royal Greenwich Observatory.
Viewing the Seven Sisters Eclipse
The Seven Sisters eclipse is not a spectacularly rare occurrence in and of itself. Indeed, according to Time and Date, the event has been taking place every month since September 2023 and is set to do so until July 2029. However, depending on whereabouts, it may or may not be visible as it can only be viewed from certain locations each month.
“The Moon changes its position in the sky relative to the background stars, completing one orbit every 27.3 days, so the two will next pass each other in the sky on [August 16],” says Gammon-Ross.
“However, the Moon’s altitude in the sky varies as it orbits, so sometimes the Moon will pass above the Pleiades, sometimes below it, and sometimes, like in the case of [July 20], it will pass right in front of it,” continues Gammon-Ross.
Read More: Seven Planets Will Soon Align, Creating a Planet Parade in the Sky
What Are the Pleiades?
The Pleiades (pronounced Ply-a-dees) go by many names. This includes the astronomical name “Messier 45” (M45) and, more informally, “the Seven Sisters.”
The name Pleiades derives from Greek mythology – specifically the seven daughters of Atlas, a Titan forced to hold up the heavens. According to legend, Zeus transformed the sisters into stars to protect them from the hunter Orion, and only one of the sisters went into hiding after falling in love with a mortal. Most people can only see six stars without a telescope.
Even with the Seven Sisters name, the Pleiades contain more than a thousand young stars bound together by gravity, the brightest of which can be viewed with the naked eye. The stars emit a luminous blue light thanks to their ultra-high temperature. Surrounding clouds of gas and dust (called nebulae) cast a hazy blue glow around the star formation.
It is an open cluster, meaning all the stars were formed around the same time. In this case, approximately 100 million years ago – when tyrannosaurus and velociraptors still roamed the planet.
The Pleiades are in the constellation of Taurus, some 445 million light years away from Earth, and are considered winter stars. This is because, while the eclipse is set to occur in July, the best time to spot the Seven Sisters from the Northern Hemisphere is between October and April.
Other Events to See in July 2025
There are a few other celestial events to watch out for in July 2025. On July 21 and 22, Venus will appear near the crescent moon with Jupiter close to the horizon. Towards the very end of the month, on July 28, 2025, Mars can be spotted next to the crescent moon.
Skywatchers can also catch the constellation Aquila the eagle, which can be found in the eastern part of the sky throughout the first half of the night throughout the month.
Read More: Get Ready for the 2025 Buck Moon — The Farthest Full Moon from the Sun and the First of the Summer
Article Sources
Our writers at Discovermagazine.com use peer-reviewed studies and high-quality sources for our articles, and our editors review for scientific accuracy and editorial standards. Review the sources used below for this article:
Rosie McCall is a freelance writer living in London. She has covered science and health topics for publications, including IFLScience, Newsweek, and Health.
