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  ✦

Stars and Dust Across Corona Australis

September 12, 2013
© Ignacio Diaz Bobillo
Cosmic dust clouds sprawl across a rich field of stars in this sweeping telescopic vista near the northern boundary of Corona Australis, the Southern Crown. Less than 500 light-years away the dust clouds effectively block light from more distant background stars in the Milky Way. The entire frame spans about 2 degrees or over 15 light-years at the clouds' estimated distance. Near center is a group of lovely reflection nebulae cataloged as NGC 6726, 6727, 6729, and IC 4812. A characteristic blue color is produced as light from hot stars is reflected by the cosmic dust. The dust also obscures from view stars in the region still in the process of formation. Smaller yellowish nebula NGC 6729 surrounds young variable star R Coronae Australis. Below it are arcs and loops identified as Herbig Haro objects associated with energetic newborn stars. Magnificent globular star cluster NGC 6723 is at the right. Though NGC 6723 appears to be part of the group, its ancient stars actually lie nearly 30,000 light-years away, far beyond the young stars of the Corona Australis dust clouds.

Customized Star Charts Coming 1st Quarter 2027

We respect your privacy. Unsubscribe at any time.

✦  EarthSky  ·  Astronomy.com  ·  Phys.org  ✦
Earth Sep 13, 2026

Crepuscular rays are sunrays in twilight skies

Crepuscular rays form around twilight when particles in the atmosphere reflect the sun's light beams toward our eyes. See photos of the phenomenon here.

Read
Observing Sep 13, 2026

The Sky Today on Sunday, September 13: Venus, the Moon, and Spica

Looking for a sky event this week? Check out our full Sky This Week column.  September 12: Dione skims Saturn’s pole Blazing at magnitude –4.8, Venus is nearing its greatest illu…

Read
Observing Sep 12, 2026

2026 Full Moon calendar: When to see the Full Moon and phases

The phenomenon of a Full Moon arises when our planet, Earth, is precisely sandwiched between the Sun and the Moon. This alignment ensures the entire side of the Moon that faces us gleams under sunl…

Read
Robotic Spaceflight Sep 12, 2026

Sept. 12, 1959: Luna 2 launches

Less than two years after the successful launch of Sputnik 1, the Soviet Union put a spacecraft on the Moon. Launched Sept. 12, 1959, Luna 2 traveled over 30 hours to crash-land on the lunar surfac…

Read
Astronomy Sep 12, 2026

Why are the stars around our galaxy's black hole missing their companions?

A new study suggests that the young stars orbiting the Milky Way's central black hole may have a surprisingly ordinary origin. But the black hole's influence may be what makes their origin look mor…

Read
Today's Image Sep 12, 2026

Does this Mars image show an alien in a hallway?

What do you see in the Mars image? Some people think the rocks look like a hallway where a little alien is walking. Other instances of pareidolia, here.

Read
Astronomy Sep 12, 2026

Rubin observatory peers deep into the famous COSMOS field

The COSMOS field, or Cosmic Evolution Survey Deep Field, is one of the most famous patches of the universe observed by astronomers. Located in the constellation Sextans, this region was photographe…

Read
Earth Sep 12, 2026

Atlantic hurricane season sets a record: No hurricanes yet!

The 2026 Atlantic hurricane season has set a record. It's the longest we've ever gone in a hurricane season without seeing a hurricane. Read more here.

Read
Astronomy Sep 11, 2026

How big can the universe's first starbursts get?

As our telescopes have improved and we've been able to peer farther back in time, we've begun finding more fascinating features of the universe. But one thing we haven't found for sure is Populatio…

Read