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 Cloudy Cores of Active Galaxies

February 24, 2014
What would it look like to travel to the center of an active galaxy? Most galactic centers are thought to house black holes millions of times more massive than our Sun. The spaces surrounding these supermassive black holes may be far from dormant, however, flickering in many colors and earning the entire object class the title of Active Galactic Nuclei (AGN). Pictured above is a video illustrating how an active galactic nucleus may appear up close. AGN typically sport massive accretion disks feeding the central black hole, as well as powerful jets shooting electrically charged matter far into the surrounding universe. Clouds of gas and dust seen orbiting the central black holes have recently been found to be so dense that they intermittently eclipse even penetrating x-rays from reaching us. These X-ray dimming events, as short as hours but as long as years, were detected in an analysis encompassing over a decade of data taken by the NASA's orbiting Rossi X-ray Timing Explorer (RXTE).

Customized Star Charts Coming 1st Quarter 2027

We respect your privacy. Unsubscribe at any time.

✦  EarthSky  ·  Astronomy.com  ·  Phys.org  ✦
Astronomy Sep 28, 2026

Hydrogen's distant glow opens new way to investigate dark energy

The Canadian Hydrogen Intensity Mapping Experiment (CHIME) has shown for the first time that it can detect the faint glow of hydrogen gas from deep in the universe's past using only its own data.

Read
Astronomy Sep 28, 2026

Testing tiny telescope robots reveals design changes that could improve galaxy maps

Astronomers have cataloged billions of stars and hundreds of billions of galaxies. We have found thousands of planets orbiting stars. We can also map where galaxies sit and trace how the universe c…

Read
Astronomy Sep 28, 2026

A tiny stellar system may be a 'satellite of a satellite'

Astronomers using data from the Euclid space telescope have discovered an exceptionally faint stellar system near the Fornax dwarf galaxy. Called Fornax-7, it appears to contain only about 170 time…

Read
Observing Sep 28, 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
Today in the History of Astronomy Sep 28, 2026

Sept. 28, 1969: The Murchison Meteorite explodes over Australia

At 10:58 AM on Sept. 28, 1969, residents of the small Australian farming community of Murchison, Victoria, heard a series of loud booms. The noise was accompanied by a strong smell and a streak of …

Read
Earth Sep 28, 2026

The Komodo dragon is the world’s largest living lizard

The Komodo dragon is the world’s largest lizard. It's a venomous predator that can hunt, swim between islands and reproduce without a mate.

Read
Astronomy Essentials Sep 28, 2026

Visible planets and night sky guide late September and October

Visible planets and night sky guide. Tonight, look for the bright waning gibbous moon near planet Saturn and the Pleiades star cluster.

Read
Sun Sep 28, 2026

Sun news: Fast solar wind fades, quiet sun returns

Sun news September 28, 2026: The coronal hole stream has faded, and the sun stayed quiet with only small C flares. Calm conditions should hold for a few days.

Read
Observing Sep 28, 2026

The Sky Today on Monday, September 28: Open cluster M39 shines

Looking for a sky event this week? Check out our full Sky This Week column.  September 27: Catch Saturn’s satellites Although the Moon still dominates much of the night, bright dee…

Read