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  ✦

Star Forming Region NGC 3582

June 11, 2013
© Desert Hollow Observatory
What's happening in the NGC 3582 nebula? Bright stars and interesting molecules are forming. The complex nebula resides in the star forming region called RCW 57. Visible in this image are dense knots of dark interstellar dust, bright stars that have formed in the past few million years, fields of glowing hydrogen gas ionized by these stars, and great loops of gas expelled by dying stars. A detailed study of NGC 3582, also known as NGC 3584 and NGC 3576, uncovered at least 33 massive stars in the end stages of formation, and the clear presence of the complex carbon molecules known as polycyclic aromatic hydrocarbons (PAHs). PAHs are thought to be created in the cooling gas of star forming regions, and their development in the Sun's formation nebula five billion years ago may have been an important step in the development of life on Earth. The above image was taken at the Desert Hollow Observatory north of Phoenix, Arizona, USA. Follow APOD on: Facebook (Daily) (Sky) (Spanish) or Google Plus (Daily) (River)

Customized Star Charts Coming 1st Quarter 2027

We respect your privacy. Unsubscribe at any time.

✦  EarthSky  ·  Astronomy.com  ·  Phys.org  ✦
Space Sep 3, 2026

Saturn’s south pole decagon confirmed! A mysterious 10-sided figure

Saturn’s south pole is now known to have a giant, evolving 10-sided wave, similar to the Saturn north pole hexagon. Read more about it here.

Read
Robotic Spaceflight Sep 3, 2026

Sept. 3, 1976: Viking 2 reaches Mars

Only a little over a month after Viking 1 landed on Mars, Viking 2 followed suit. Though the two Viking landers touched down in different locations, they used identical spacecraft and had the same …

Read
Astronomy Sep 3, 2026

The biggest black hole merger ever observed could be less massive than it appears

Gravitational waves are ripples in spacetime created when pairs of black holes spiral into each other and eventually merge. But if this ripple has been warped by another massive object on its way t…

Read
Earth Sep 3, 2026

Hurricane triplets spin across the Pacific Ocean

Rare hurricane triplets are currently spinning across the Pacific Ocean: Lowell, Karina and Marie. Did El Niño play a part? Find out here.

Read
Space Sep 3, 2026

BepiColombo mission 1 step closer to Mercury today

The BepiColombo mission has been maneuvering its way into orbit around Mercury for 8 years. On September 3, it successfully released 2 orbiters.

Read
Observing Sep 3, 2026

The Sky Today on Thursday, September 3: The Moon in Taurus

Looking for a sky event this week? Check out our full Sky This Week column.  September 2: Venus south of Spica The Moon passes 5° north of Uranus at 7 P.M. EDT. However, you’ll wa…

Read
Sep 2, 2026

Clawing through Cassiopeia

Luigi La Bella from Melilli, Italy The Lobster Claw Nebula (Sharpless 2-157) is a faint emission nebula straddling the constellations Cassiopeia and Cepheus. This complex of gas and dust has been s…

Read
Astronomy Sep 2, 2026

Hubble tracks new decagon encircling Saturn's south pole

Recent observations with NASA's Hubble Space Telescope have revealed a giant, evolving, 10-sided atmospheric wave encircling Saturn's south pole. This discovery marks the first time a large, regula…

Read
Astronomy Sep 2, 2026

Hawai'i high school students name image of glittering galaxy pair

Nā ʻUhane Māhoe Huki Pū i ke Ola is the Hawaiian name given to NGC 7253—a pair of spiral galaxies caught in each other's gravity. Captured by the Gemini North telescope on Maunakea in Hawai'i…

Read