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  ✦

Bright Planetary Nebula NGC 7027 from Hubble

August 26, 2013
It is one of the brightest planetary nebulae on the sky -- what should it be named? First discovered in 1878, nebula NGC 7027 can be seen toward the constellation of the Swan (Cygnus) with a standard backyard telescope. Partly because it appears there as only an indistinct spot, it is rarely referred to with a moniker. When imaged with the Earth-orbiting Hubble Space Telescope, however, great details are revealed. Studying Hubble images of NGC 7027 have led to the understanding that it is a planetary nebula that began expanding about 600 years ago, and that the cloud of gas and dust is unusually massive as it appears to contain about three times the mass of our Sun. Pictured above in assigned colors, the resolved, layered, and dust-laced features of NGC 7027 might remind sky enthusiasts of a familiar icon that could be the basis for an informal name. Please feel free to make suggestions -- some suggestions are being recorded, for example, in an online APOD discussion forum.

Customized Star Charts Coming 1st Quarter 2027

We respect your privacy. Unsubscribe at any time.

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

eROSITA's second data release catalog delivering most comprehensive high-energy census of the cosmos to date

The eROSITA (extended ROentgen Survey with an Imaging Telescope Array) telescope, the primary instrument aboard the Russian-German Spektr-RG space observatory, was developed by the Max Planck Insti…

Read
Robotic Spaceflight Sep 11, 2026

Sept. 11, 1985: The ICE probe encounters Comet Giacobini-Zinner

Launched as the International Sun-Earth Explorer-3 in 1978, a joint NASA-ESA mission, the ISEE-3 probe studied the solar wind and Earth’s magnetic field from the L1 Lagrange point. When its missi…

Read
Space Sep 11, 2026

Did the sun swallow a planet early in its history?

Did the sun swallow a planet early in its history? Models show a super-Earth might have spiraled into the sun and left a fingerprint we can still see today.

Read
Space Sep 11, 2026

Distant proto-supercluster! An early intersection point in the cosmic web?

Astronomers have found the most distant proto-supercluster yet, an early collection of galaxies at a junction in the cosmic web.

Read
Earth Sep 11, 2026

International Cloud Appreciation Day is September 11

The international Cloud Appreciation Day is September 11, 2026. Learn how to participate here and see a gallery of beautiful clouds.

Read
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
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