November 5, 2025: The Beaver Moon reaches its full phase near perigee, appearing slightly larger and brighter in the sky. Learn why the so-called “supermoon” looks so big when rising — it’s the Moon Illusion, not a true size change.
by Jeffrey L. Hunt
Chicago, Illinois: Sunrise, 6:28 a.m. CST; Sunset, 4:40 p.m. CST. Times are calculated by the US Naval Observatory’s MICA computer program. Check local sources for sunrise and sunset times.
Related Articles
Venus Summary Article
Beaver Moon
The bright moon appears farther westward during this Beaver Moon morning. The lunar orb is opposite the sun this morning at 7:19 a.m. Central Time, while still above the horizon across most of North America.
An hour before sunrise, the moon is in the west-northwest, near Hamal, Aries’ brightest star. Use a binocular to spot the star in the moonlight.
Perigee Moon
The moon is closest to Earth (perigee) at 4:27 p.m. Central Time. When a full moon occurs near perigee, it appears slightly larger and brighter than average. The popular press calls these “supermoons,” and the term often captures public attention. Expect to see many images of the Super Beaver Moon during the next few news and social media cycles.
At perigee, the moon’s apparent size is about 14% larger and marginally brighter — changes that are subtle to the unaided eye. The atmosphere reddens the sun and moon and slightly distorts their shapes when they are near the horizon.
Moon Illusion
There is an interesting effect to explore when the full moon, or any lunar phase, is near the horizon — either rising or setting — around sunset or sunrise. The moon, as well as the sun and constellations, appears larger near the horizon than when higher in the sky. This is known as the Moon Illusion.
While not the first to describe the effect, my colleague and close friend, Dr. Carl Wenning, retired from Illinois State University, provided an intriguing explanation. When the moon is near the horizon, it seems farther away, and the lunar orb looks larger than when higher in the sky. We perceive the horizon as more distant than the overhead sky.
To illustrate, Wenning suggests creating an afterimage by briefly looking at a light bulb. Our eyes respond similarly after a camera flash when we “see spots.” The effect is temporary but useful. When viewing a nearby surface, the afterimage looks smaller than when viewed against a distant wall. The afterimage itself is the same size, but it appears larger when seen against a more distant background. The Moon Illusion is explained in the same way — the moon looks larger because it is seen against a more distant horizon than when higher in the sky, which seems closer.
If you have the opportunity to see the moon near the horizon, notice how large it appears. The moon rises in the east-northeast near sunset. Watch it as it climbs into the night sky and note its apparent size compared to the distant horizon.
As the season progresses and Orion climbs into the eastern sky, look for the same effect. Early risers can see Orion perform the illusion in the western sky before morning twilight.
If you are outside when the moon is near the horizon during the next few nights, some may attribute its seemingly large size to the “supermoon.” It’s just the Moon Illusion.
LATEST ARTICLES
- 2026, September 25: Watch Mars Align with the Gemini Twins as it Approaches Jupiter
September 25, 2026: Mars lines up with Castor and Pollux before sunrise while Jupiter shines brightly near Regulus. Watch the Red Planet close the gap to the Jovian Giant ahead of their November conjunction. - 2026, September 24: Venus in Bright Twilight While the Harvest Moon Nears Saturn
September 24, 2026: Brilliant Venus shines through bright twilight while the Harvest Moon approaches Saturn. Before sunrise, Jupiter dominates the morning sky and Mars aligns with Castor and Pollux. - 2026, September 23: Venus at Greatest Brilliancy
September 23, 2026: Venus reaches greatest brilliancy tonight as it moves toward inferior conjunction on October 23. Look for the brilliant Evening Star low in the west-southwest during evening twilight. - 2026, September 22: Autumnal Equinox 2026: Daylight, the Ecliptic, and the Harvest Moon Effect
September 22, 2026: The autumnal equinox occurs today. Learn why daylight and darkness are not exactly equal, how the ecliptic changes angle with the horizon, and why the Harvest Moon rises at nearly the same time each evening. - 2026, September 21: Harvest Moon Nights Begin as Venus and Jupiter Dominate the Sky
September 21, 2026: Venus nears its greatest brilliancy while the Harvest Moon grows brighter each evening. Saturn rises earlier as opposition approaches, and Jupiter and Mars dominate the predawn sky.