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  ✦

Night of the Long Leonid

November 22, 2012
© Stéphane Vetter
A cosmic grain of sand left the long and colorful trail across this all-sky view. Its grazing impact with planet Earth's atmosphere began at 71 kilometers per second. With the Milky Way stretching from horizon to horizon, the scene was captured on the night of November 17 from the astronomically popular high plateau at Champ du Feu in Alsace, France. Of course, the earthgrazer meteor belongs to this month's Leonid meteor shower, produced as our fair planet annually sweeps through dust from the tail of periodic Comet Tempel-Tuttle. The shower's radiant point in the constellation Leo is very close to the eastern horizon, near the start of the trail at the lower left. Bright planet Jupiter is also easy to spot, immersed in a faint band of Zodiacal light just below and right of center. The image is part of a dramatic time-lapse video (vimeo here) that began only 7 minutes before the long leonid crossed the sky.

Customized Star Charts Coming 1st Quarter 2027

We respect your privacy. Unsubscribe at any time.

✦  EarthSky  ·  Astronomy.com  ·  Phys.org  ✦
Sep 4, 2026

The aftermath of a solar flare

Mark Johnston from Scottsdale, Arizona On Aug. 21, 2026, an unusually long-lasting M-class flare erupted from a sunspot group near the Sun’s west limb. As the flare’s stretched magnetic fie…

Read
Today in the History of Astronomy Sep 4, 2026

Sept. 4, 973 C.E.: The birth of al-Biruni

Born in Kath, Khwarezm – a region that today would be cover parts of Uzbekistan, Kazakhstan, and Turkmenistan – Abu Raihan Muhammad al-Biruni was a man of many scientific talents. His extensive…

Read
Space Sep 4, 2026

Mars’ southern hemisphere is unusually hot deep underground

A new study from Caltech shows that Mars' southern hemisphere is much hotter than expected deep below the surface. Why is that?

Read
Sun Sep 4, 2026

Sun news: More action from returning sunspot region

Sun news September 4, 2026: Returning region AR4524 fired an M1.2 flare. Its last pass across the Earth-viewed sun was promising, so stronger flares may follow.

Read
Astronomy Essentials Sep 4, 2026

Visible planets and night sky guide for September

Visible planets and night sky guide: The moon reaches 3rd quarter today, rising about midnight to set around noon. Look for the daylight moon tomorrow morning!

Read
Observing Sep 4, 2026

The Sky Today on Friday, September 4: Get in a workout

Looking for a sky event this week? Check out our full Sky This Week column.  September 3: The Moon in Taurus Last Quarter Moon occurs at 3:51 A.M. EDT, leaving our evening sky comple…

Read
Astronomy Sep 3, 2026

Hot subdwarfs come into focus as AI scans thousands of stars in Gaia data

There are myriad ways of "being a star," and scientists spend years trying to uncover and understand them. One unusual type is the so-called hot subdwarf—small stars that burn mysteriously hot fo…

Read
Astronomy Sep 3, 2026

Photo: NASA's Hubble spies superbubble scene

This NASA/ESA Hubble Space Telescope image features a sprawling cosmic vista in the Large Magellanic Cloud, or LMC, the largest of the small galaxies that orbit our Milky Way galaxy. At just 160,00…

Read
Astronomy Sep 3, 2026

Newly discovered 1666 manuscript may trace four-lens telescope experiments to Galileo

A potentially history-altering finding by a University of Limerick researcher may provide the most detailed technical analysis of a telescope demonstrably made by the famous astronomer and scientis…

Read