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  ✦

The Magellanic Stream

August 15, 2013
In an astronomical version of the search for the source of the Nile, astronomers now have strong evidence for the origin of the Magellanic Stream. This composite image shows the long ribbon of gas, discovered at radio wavelengths in the 1970s, in pinkish hues against an optical all-sky view across the plane of our Milky Way galaxy. Both Large and Small Magellanic Clouds, dwarf satellite galaxies of the the Milky Way, are seen near the head of the stream at the right. Data from Hubble's Cosmic Origins Spectrograph were used to explore abundances of elements along sightlines to quasars that intersect the stream. The results indicate that most of the stream's material comes from the Small Magellanic Cloud. The Magellanic Stream is likely the result of gravitational tidal interactions between the two dwarf galaxies some 2 billion years ago, the Small Magellanic Cloud losing more material in the encounter because of its lower mass. Gallery: New Bright Nova in Delphinus

Customized Star Charts Coming 1st Quarter 2027

We respect your privacy. Unsubscribe at any time.

✦  EarthSky  ·  Astronomy.com  ·  Phys.org  ✦
Observing Sep 11, 2026

The Sky Today on Friday, September 11: Visit the Deer Lick Group

Looking for a sky event this week? Check out our full Sky This Week column.  September 10: Uranus is stationary With dark, moonless skies tonight, let’s go galaxy hunting. By 9 P.M…

Read
Sky This Week Sep 11, 2026

The Sky This Week from September 11 to 18: Catch the zodiacal light

Friday, September 11Already high in the north after sunset, the planetary nebula NGC 6543 in Draco is famously called the Cat’s Eye Nebula. It’s best seen with a large telescope, but even a sma…

Read
Astronomy Sep 10, 2026

Ancient Swedish Goths had surprisingly accurate calendars

On a mostly flat plain an hour north of Stockholm lies a collection of large burial mounds dating from an ancient culture at least 2,500 years old. These people were not Vikings; they were northern…

Read
Science Sep 10, 2026

Artemis 2 crew lands at Starmus VII — 15 years after Armstrong, Aldrin, and Leonov launched its lengacy

TENERIFE, Canary Islands, Sept. 8, 2026 — Fifteen years after STARMUS brought together the legends who defined the first age of human space exploration, the Festival will welcome the explorers wh…

Read
Astronomy Sep 10, 2026

Continuous video of black hole radio observations challenges shock wave theory

For years, scientists have relied primarily on radio imaging from techniques like very long baseline interferometry (VLBI) to study jets from the active galactic nuclei of supermassive black holes.…

Read
Astronomy Sep 10, 2026

A galaxy with almost no stars? New Cloud-9 observations strengthen the case

Astronomers have taken one of the deepest looks yet at Cloud-9, a candidate "dark galaxy," and found no trace of stars. The paper outlining this discovery was posted to the arXiv preprint server on…

Read
Space Sep 10, 2026

Do black holes have hidden hair? Scientists are searching

If black holes have extra matter around them - aka hidden hair - astronomers could find it by measuring the different characteristics of these ripples.

Read
Astronomy Essentials Sep 10, 2026

Zodiacal light: Start watching for it now

The zodiacal light is an eerie light extending up from the horizon before dawn around the Northern Hemisphere autumn. Southern Hemisphere? Look after sunset!

Read
Earth Sep 10, 2026

What is an Equal Earth projection map? See comparisons here

Everyone is familiar with the Mercator map, a flattened view of Earth. But what is the Equal Earth projection map, and how does it compare?

Read