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What is a waning gibbous moon?
The waning gibbous moon falls between the full and last quarter moon. Watch for it to rise late at night. Or see it in the west in the morning.
January 1, 2026
Sky measurements: Degrees, arcminutes and arcseconds
What are sky measurements - or distances - in the night sky? Here's what it means for objects to be several degrees (or arcminutes or arcseconds) apart.
January 1, 2026
4 keys to understanding moon phases
As the moon circles Earth, we see different fractions of its lighted face: the changing moon phases. Here are 4 tips for understanding them.
January 1, 2026
What is a new moon? It rises and sets with the sun
The new moon generally can't be seen, except during a solar eclipse. The moon crosses the sky with the sun during the day, and its shadow side faces Earth.
January 1, 2026
What’s the youngest moon you can see with your eye alone?
It has long been a sport for skywatchers to spot the youngest moon after sunset, with the eye alone. What does it take to see a very young crescent moon?
January 1, 2026
How often are there three eclipses in one month?
We last had three eclipses in one lunar month in 2020. It'll next happen in the year 2029. From 2000-2050, there are 3 eclipses in one lunar month 14 times.
January 1, 2026
What is a waxing crescent moon?
A waxing crescent moon shines in the west after sunset, first visible a day or two after new moon with earthshine. It sets after the sun after sunset.
January 1, 2026
Uranus at opposition on November 25, 2026
Don't miss Uranus at opposition on November 25, 2026. At this time, it's brightest for the year and visible to the eye under optimum observing conditions.
January 1, 2026
How to know your eclipse glasses are safe
Unscrupulous companies are printing ISO certification labels on fake eclipse glasses. Check here for reputable vendors from the American Astronomical Society.
January 1, 2026
Rare alignment of Earth, moon and sun in early January
There will be a rare alignment of Earth, the moon and the sun in early January. The moon will be a supermoon on the same date that Earth is closest to the sun.
December 31, 2025
