What Is a Supermoon? The Truth Behind the Hype
So what is a supermoon, and does it really deserve the hype? A supermoon happens when a full Moon lines up with the closest point in its orbit, making it look slightly bigger and brighter than usual. The Moon does not travel in a perfect circle, so its distance from Earth changes a little each month, and once in a while a full Moon arrives right when it is nearest. The result is real, but gentler than the headlines suggest.
What is a supermoon, really?
The Moon's orbit is a soft oval, so there is a near point (perigee) and a far point (apogee). When a full Moon falls close to perigee, we get a supermoon. At its closest, the full Moon can appear up to about 14% wider and 30% brighter than a full Moon at its farthest. That sounds dramatic, but side by side with an ordinary full Moon the difference is subtle to the naked eye.
Why supermoons look so huge near the horizon
Most of the "wow, it is enormous" moments actually come from the Moon Illusion, not the supermoon itself. When the Moon hangs low near the horizon, your brain compares it to trees, hills, and buildings and reads it as gigantic. The same Moon high overhead looks smaller, even though it is the same size. So a low, golden, rising Moon will always impress you, supermoon or not.
How to enjoy a supermoon
You need no equipment at all, just clear skies and a good view toward the east as the Moon rises. A little planning turns it into a memorable evening.
- Watch as the full Moon rises near sunset, when it sits low and looks largest.
- Find a spot with an open eastern horizon, like a hill, beach, or rooftop.
- Frame it next to trees or buildings to amplify the Moon Illusion.
- Bring binoculars to trace craters along the line between light and shadow.
- Remember the bright Moon washes out fainter stars, so save deep-sky targets for another night.
If you want to understand why the Moon changes shape at all, our guide to why moon phases happen makes it click, and you can see what else is up with our roundup of what is in the sky tonight.
Curious when the next full Moon rises where you live? Open the Starly sky map to see the Moon's exact position, phase, and rise time from your location, and step outside ready to catch it.
Open the sky map with the Moon selected and see where it rises tonight.
Frequently asked questions
What is a supermoon in simple terms?
A supermoon is a full Moon that happens when the Moon is near the closest point in its orbit to Earth, called perigee. This makes it look slightly larger and brighter than an average full Moon, though the difference is subtle to the naked eye.
How much bigger does a supermoon look?
At its closest, a supermoon can appear up to about 14% wider and 30% brighter than a full Moon at its farthest point. Most of the dramatic size you notice near the horizon actually comes from the Moon Illusion, not the supermoon itself.