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.

✦  Astronomy Picture of the Day  ✦

Rock Nest Panorama from Curiosity on Mars

June 25, 2013
This is Mars -- have a look around. More specifically, this is one area picked for its promise of holding clues to the habitability of Mars to ancient life. To better search for telling leads, the robotic Curiosity rover took a series of detailed images from a location called Rock Nest. Over 900 of these images were then composed into one of the highest resolution images ever created of the red planet -- a composite containing over one billion pixels. Shown above, toward the middle of this image mosaic, is Mt. Sharp, the central peak of the large crater where the Curiosity rover landed and is currently exploring. An interactive and zoomable version of this image is available here. Over the next few years, Curiosity is scheduled to roll toward the peak of ancient Mt. Sharp, all the while keeping a lookout for distinguishing geological and chemical markers.

Customized Star Charts Coming 1st Quarter 2027

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✦  EarthSky  ·  Astronomy.com  ·  Phys.org  ✦
Astronomy Sep 6, 2026

'Quiet' pulsar suddenly reveals three glitches in 15 years of observations

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Space Sep 6, 2026

Small asteroid impact today over the ocean near Australia

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These microbes in Antarctica don’t live anywhere else

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Labor Day: Learn its history and traditions

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The Sky Today on Sunday, September 6: The Moon and Mars in Gemini

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Astronomy Sep 5, 2026

FAST finds two mysterious hydrogen clouds with no visible stars

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Astronomy Sep 5, 2026

A black hole as light as 40 tons can exist inside a star if dark matter helps

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Robotic Spaceflight Sep 5, 2026

Sept. 5, 2001: The Milky Way has a black hole

NASA’s Chandra X-Ray Observatory is the agency’s flagship mission for X-ray astronomy. On Sept. 5, 2001, NASA announced that astronomers using Chandra in October of the previous year had witnes…

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Observing Sep 5, 2026

The Sky Today on Saturday, September 5: Titan near Saturn

Looking for a sky event this week? Check out our full Sky This Week column.  September 4: Get in a workout Titan, Saturn’s brightest moon, orbits its parent world with a period of about 16 day…

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