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.
The Tulip in the Swan
Customized Star Charts Coming 1st Quarter 2027
We respect your privacy. Unsubscribe at any time.
Dense galaxies are carving out a bubble in the early universe
When JWST's first science results started rolling in, it was a triumph for scientific vision and persistence. For years, the fate of the powerful space telescope was uncertain. It went way over bud…
ReadActive black holes reveal star-forming rings and shock waves in nine nearby galaxies
A new study of nine nearby galaxies has shown that actively growing supermassive black holes may contribute to, rather than prevent, star formation in their host galaxies.
ReadEurope launches two Earth-observation satellites amidst a busy week for China
Rocket launches this week On Monday, Sept. 14 at 9:21 p.m. EST, Avio — a publicly traded Italian aerospace company headquartered near Rome — is set to launch a Vega C rocket from the Guiana Spa…
ReadPhysicists zoom into the birth of cosmic rainstorms with new CERN study
Every second, particles zip through your body at nearly the speed of light. They rain down from a storm high in the sky, where cosmic rays, a powerful type of interstellar matter, constantly strike…
ReadSept. 14, 1915: The birth of John Dobson
On Sept. 14, 1915, John Dobson was born in Bejing. His family moved to San Francisco to avoid political turmoil in China in 1927, and Dobson went on to attend the University of California, Berkeley…
ReadWhy do bars form in some spiral galaxies, but not in others?
Why do bars form in some spiral galaxies, but not in others? Joe RuszHerndon, VA We believe that stellar bars can form in any galaxy that displays ordered rotation. This includes galaxies with disk…
ReadVisible planets and night sky guide for September
Visible planets and night sky guide: Venus reaches its brightest in the sky this week. Don't miss it near the thin moon tonight.
ReadSun news: Violent filament eruption last night
Sun news September 14, 2026: A violent filament eruption sent plasma into space. Initial analysis suggests a glancing blow at Earth on September 17.
ReadVenus brightest in the evening sky this week
See Venus brightest in the evening sky this week, with greatest brilliancy coming around September 18, 2026. Look west after sunset.
Read