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Earthshine is a lovely glow on the unlit portion of the moon

Earthshine - the dim glow on the darkened portion of a crescent moon - is light from Earth cast on the night side of the moon. Watch for it around the new moon.

Editors of EarthSky

January 1, 2026

Saturn at opposition – brightest for 2026 – on October 4

Don't miss Saturn at opposition on and around the night of October 4, 2026. That's when our planet Earth passes between the sun and Saturn.

Editors of EarthSky

January 1, 2026

Radiant point of meteor showers: All you need to know

Meteors enter Earth's atmosphere on parallel paths. So, you'll see meteors appear to come from a single point in the sky: the radiant point!

Editors of EarthSky

January 1, 2026

Why is there no eclipse every full and new moon?

If the moon orbited Earth on the same plane that Earth circles the sun, we'd have an eclipse at every full and new moon. Here's why we don't.

Editors of EarthSky

January 1, 2026

Greatest elongation, superior and inferior conjunction

When Mercury and Venus are as far from the sun as they get from our earthly point of view, they are at greatest elongation. It is the best time to observe them.

Kelly Kizer Whitt

January 1, 2026

The moon illusion makes the moon look huge!

When you see a large-looking moon low in the sky, does the moon look bigger to you? That's the moon illusion that makes the moon look so big.

Deborah Byrd

January 1, 2026

What is stellar magnitude?

The brightest stars to the eye are 1st magnitude, and dimmest stars to the eye are 6th magnitude. How does stellar magnitude work in astronomy?

Bruce McClure

January 1, 2026

Neptune at opposition on September 26, 2026

Neptune at opposition - when it's 180 degrees from the sun on the sky's dome - comes on September 26, 2026. You'll need optical aid to spot it.

Editors of EarthSky

January 1, 2026

What is the zodiac? Why is it important in astronomy?

Maybe you associate the word zodiac with astrology. But it has an honored place in astronomy, too. It's defined by the path of the sun across our sky.

Christopher Crockett

January 1, 2026