The Rhythm of the Spheres

Reading the Night Sky

Wandering in Astronomy

The night sky is the oldest pattern of man, and every culture reads it differently. The stars above keep silent time, moving to a rhythm we are just now beginning to understand. Astronomy is where math, science, art, music, and words meet in a wondrous collision. In this section of our site, learn the basics of astronomy: from how a star chart is made, to projections and art that map the night sky, to how an astrolabe works just like it did thousands of years ago. Watch the North Star shift across centuries, explore how one sky has been mapped by many traditions, read what happened on this day in space, and see tonight’s moon for your location.

Map the Stars

The math behind star charts, with a projection explorer and a working astrolabe.

The Moving Sky

How the sky shifts across centuries, with a precession clock you can run.

The Traditions

One sky reads many ways, with a same-sky overlay of the world’s constellations.

This Day in the Stars

The sky’s events, discoveries, and lore tied to today’s date.

The Moon Tonight

Its phase and face, drawn live for where you’re standing.

โœฆ  Astronomy Picture of the Day  โœฆ

Firefall by Moonlight

May 7, 2022
Credit: Tara Mostofi
See this entry on NASA's APOD โ†’
On certain dates in February, an elusive firefall can be spotted at sunset in Yosemite National Park , when water flows, the weather cooperates and the direction to the setting Sun is just right. Often photographed from vantage points below, at the right moment the park's seasonal Horsetail Fall is isolated in the shadows of the steep walls of El Capitan . Then, still illuminated with rays of reddened sunlight the waterfall briefly takes on a dramatic, fiery appearance. But a Horsetail firefall can be photographed by moonlight too. Even more elusive by moonlight, the firefall effect can also be seen when a bright Moon sets at the right direction along the western horizon. And skies were clear enough for this well-planned imaging of an ephemeral Horsetail firefall , lit by a bright gibbous Moon setting in the early morning hours of April 15.

Customized Star Charts Coming 1st Quarter 2027

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โœฆ  EarthSky  ยท  Astronomy.com  ยท  Phys.org  โœฆ
Observing Nov 13, 2026

The Sky Today on Friday, November 13: Spot Mirachโ€™s Ghost

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Soul searching

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Sky This Week Nov 13, 2026

The Sky This Week from November 13 to 20: The Leonids peak

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Astronomy Nov 12, 2026

Hubble offers cosmic sampler of targets for Roman

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Astronomy Nov 12, 2026

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Astronomy Nov 12, 2026

A rare star system emits radio signals every 8 minutes

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Astronomy Essentials Nov 12, 2026

Visible planets and night sky guide for November

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Space Nov 12, 2026

โ€˜Rosetta Stone for Mars:โ€™ Martian meteorite hints at ancient life

A rare 4.1-billion-year-old Martian meteorite, Teghaza 001, provides new clues about Mars' ancient and more habitable past.

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Astronomy Essentials Nov 12, 2026

Is there a North Star for Mars?

Is there a North Star for Mars ... a guide star for future explorers? Not in any satisfying way. But Martian stargazers wouldn't lack for things to see!

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