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  ✦

A Colorful Moon

December 19, 2013
© László Francsics
The Moon is normally seen in subtle shades of grey or yellow. But small, measurable color differences have been greatly exaggerated to make this telescopic, multicolored, moonscape captured during the Moon's full phase. The different colors are recognized to correspond to real differences in the chemical makeup of the lunar surface. Blue hues reveal titanium rich areas while orange and purple colors show regions relatively poor in titanium and iron. The familiar Sea of Tranquility, or Mare Tranquillitatis, is the blue area in the upper right corner of the frame. White lines radiate across the orange-hued southern lunar highlands from 85 kilometer wide ray crater Tycho at bottom left. Above it, darker rays from crater Copernicus extend into the Sea of Rains (Mare Imbrium) at the upper left. Calibrated by rock samples from the Apollo missions, similar multicolor images from spacecraft have been used to explore the Moon's global surface composition.

Customized Star Charts Coming 1st Quarter 2027

We respect your privacy. Unsubscribe at any time.

✦  EarthSky  ·  Astronomy.com  ·  Phys.org  ✦
Astronomy Sep 23, 2026

NASA's Hubble seeks lensed supernova, marks 200,000 orbits

NASA's Hubble Space Telescope completed its 200,000th orbit around Earth on Sept. 19, marking another milestone for an observatory that continues to transform our understanding of the universe.

Read
Sep 23, 2026

A wind-blown crescent

Aloke Palsikar, taken from Pie Town, New Mexico The Crescent Nebula (NGC 6888) is an emission nebula about 5,600 light-years away in Cygnus. Its distinctive shape was formed by fast stellar winds f…

Read
Astronomy Sep 23, 2026

Roaming black holes may tell the hidden history of galaxies

If you want to understand the origins of black holes, Yale astronomers say, you need to look beyond the centers of galaxies and start searching in the nooks and crannies. That's where you'll find t…

Read
Astronomy Sep 23, 2026

SKA may detect magnetic fields on distant exoplanets

Studying exoplanets has given astronomers insights into the characteristics that could help them find life beyond Earth. For years, astronomers thought an exoplanet's location in a star's habitable…

Read
Features Sep 23, 2026

Finding light’s true nature

Light exhibits some of the strangest properties in our cosmos. It manifests as both a wave and a particle, and its speed in a vacuum is invariant. While physicists now fully grasp the way light int…

Read
Observing Sep 23, 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
Space Sep 23, 2026

Baby exoplanet: Astronomers find the youngest world yet

Astronomers have discovered the youngest-known exoplanet so far, Elias 2-24 b. The baby exoplanet is twice the mass of Jupiter and 450 light-years away.

Read
Sun Sep 23, 2026

Sun news: Solar wind gust could spark auroras

Sun news September 23, 2026: NOAA issued a G1 storm alert as coronal hole wind arrives tonight. Could the equinox effect give auroras a boost?

Read
Earth Sep 23, 2026

Hurricane Polo lurks off Mexico, now Category 4

Hurricane Polo has weakened to Category 4 as it moves north along Mexico's southwestern coast. It had strengthened from a tropical storm to Category 5 in a day.

Read