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.
All the Water on Europa
Customized Star Charts Coming 1st Quarter 2027
We respect your privacy. Unsubscribe at any time.
The Andromeda Galaxy: All you need to know
The Andromeda Galaxy is the closest large galaxy to our Milky Way. At 2.5 million light-years, it's the most distant thing you can see with the eye alone.
ReadThe Sky Today on Wednesday, September 23: Around Reiner Gamma
Looking for a sky event this week? Check out our full Sky This Week column. September 22: The autumnal equinox The bright Moon stands prominently in Aquarius the Water-bearer this e…
ReadLargest dataset of its kind could clarify how massive stars shaped early galaxies
The more astronomers learn about the universe's earliest galaxies, the stranger they seem. Many of their surprising properties may be explained by differences between their massive stars and those …
ReadAstronomers detect radio signals coming from an exoplanet for the first time
Exoplanets are exotic worlds orbiting distant stars far beyond our solar system. Ever since the first ones were discovered in the 1990s, astronomers have turned their attention to these distant wor…
ReadHow to become a variable star observer
As an astrophotographer, you might feel that you will eventually run out of targets. I disagree — amateurs are discovering new targets all the time, and old targets can look brand new with better…
ReadMilky Way's first microblazar may produce fastest particles in the galaxy
An international team of astronomers from ASTRON, JIVE, the University of Amsterdam and other institutions has found the first so-called "microblazar" in the Milky Way. This stellar system is compo…
ReadMassive star clusters drive galaxy evolution
Astronomers understand the basics of star formation. It starts in giant molecular clouds when an event — perhaps a nearby supernova or a collision with another cloud — triggers a high-density r…
ReadHurricane Polo explodes into a Category 5 storm off Mexico
Hurricane Polo has undergone rapid intensification just off the southwestern coast of Mexico. It went from a tropical storm to a category 5 hurricane in a day.
ReadVisible planets and night sky guide for September
Visible planets and night sky guide: Happy equinox! What is the equinox and why does it matter? And, most importantly, how can you experience it?
Read