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  ✦

Austrian Analemma

September 22, 2012
© Robert Pölzl
Today, the Sun crosses the celestial equator heading south at 14:49 Universal Time. An equinox (equal night), this astronomical event marks the first day of autumn in the northern hemisphere and spring in the south. With the Sun on the celestial equator, Earth dwellers will experience nearly 12 hours of daylight and 12 hours of darkness. To celebrate, consider this careful record of the Sun's yearly journey through southern Austrian skies. The scene is composed of images made at the same time each day, capturing the Sun's position on dates from September 29, 2011 through September 9, 2012. The multiple suns trace an intersecting curve known as an analemma. In fact, the past year's two equinox dates correspond to the middle (not the intersection point) of the curve. The summer and winter solstices are at the top and bottom. Of course, many would also consider it a good idea to travel the mountain road toward the left, passing the vineyards along the way to reach the nearby town of Kitzeck and toast the equinox with a glass of wine. Near the roadside bench is a windmill-like klapotetz, traditionally used in this wine-growing region to keep the birds away.

Customized Star Charts Coming 1st Quarter 2027

We respect your privacy. Unsubscribe at any time.

✦  EarthSky  ·  Astronomy.com  ·  Phys.org  ✦
Astronomy Sep 9, 2026

Beryllium signal identifies stars that have swallowed rocky planets

An international team led by researchers from the University of São Paulo (USP) in Brazil has developed an innovative method to identify stars that have consumed the planets around them. The techn…

Read
Astronomy Sep 9, 2026

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…

Read
Astronomy Sep 9, 2026

If 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…

Read
Observing Sep 9, 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 9, 2026

Sept. 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…

Read
Space Sep 9, 2026

Peptides 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.

Read
Earth Sep 9, 2026

Will 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.

Read
Earth Sep 9, 2026

Fall 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.

Read
Observing Sep 9, 2026

The 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