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.
Moon Over Andromeda
Customized Star Charts Coming 1st Quarter 2027
We respect your privacy. Unsubscribe at any time.
Chandra uncovers 'hypersoft X-ray sources' that may solve two astrophysical puzzles
Using NASA's Chandra X-ray Observatory, scientists have discovered a new class of objects behaving unlike any they have seen before. Astronomers suggest these newly spotted objects in other galaxie…
ReadIf alien civilizations use hyper-efficient computers, they will have a distinct energy signal we can detect
Love it or hate it, artificial intelligence is likely here to stay. Its ravenous need for computational power has overwhelmed chip manufacturers and power companies alike. While our current AI obse…
ReadDiscontinuity and disorder: Explaining the luminosity bump in evolved stars
Toward the end of their lives, low-mass stars undergo an abrupt dip in brightness, also known as the luminosity bump. While the endpoint of this bump is well understood, its onset has remained elus…
Read2026 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…
ReadSept. 9, 1892: Edward Emerson Barnard sees Amalthea
When Edward Emerson Barnard peered through the 36-inch refractor at Lick Observatory on Sept. 9, 1892, and spotted Amalthea, it marked the first discovery of a moon of Jupiter in 280 years. Galileo…
ReadPeptides in Venus’ clouds could form life-giving shapes
A new study from MIT shows that peptides in Venus' clouds could survive in the sulfuric acid droplets and fold into the shapes need for biological life.
ReadWill fall migration 2026 bring a billion bird night?
Will we see a billion bird night during fall migration this year? And get tips on how you can help birds by turning off exterior lights.
ReadFall hummingbird migration in progress across North America
The fall hummingbird migration typically lasts from August through October. Spot the birds in every U.S. state and Canadian province as they travel south.
ReadThe Sky Today on Wednesday, September 9: Visualize the ecliptic
Looking for a sky event this week? Check out our full Sky This Week column. September 8: The Moon joins Jupiter The waning Moon has moved from Cancer to Leo and is nearing the brigh…
Read