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 undertand. Astronomy is where math, science, art, music and words meet in a wonderous collision. On this section of our site, learn the basics, from how a star chart is actually made, to projections and art that map the night sky, to how astrolabe work the same as they did thousand years ago. Watch the North Star shift across centuries and explore how one sky has been mapped by many traditions. Check what happened on this day in space, or see tonight’s moon drawn for where you stand.

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  ✦

Interplanetary Earth

June 13, 2026
In an interplanetary first, on July 19, 2013 Earth was photographed on the same day from two other worlds of the Solar System, innermost planet Mercury and ringed gas giant Saturn. Pictured on the left, Earth is the pale blue dot just below the rings of Saturn, as captured by the robotic Cassini spacecraft then orbiting the outermost gas giant. On that same day people across planet Earth snapped many of their own pictures of Saturn. On the right, the Earth-Moon system is seen against the dark background of space as captured by the sunward MESSENGER spacecraft, then in Mercury orbit. MESSENGER took its image as part of a search for small natural satellites of Mercury, moons that would be expected to be quite dim. In the MESSENGER image, the brighter Earth and Moon are both overexposed and shine brightly with reflected sunlight. Destined not to return to their home world, both Cassini and MESSENGER have since retired from their missions of Solar System exploration.

Customized Star Charts Coming 4th Quarter 2026

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✦  EarthSky  ·  Astronomy.com  ·  Phys.org  ✦
Astronomy Jun 17, 2026

Are alien probes hiding in our backyard? A new study says we've barely looked

Even at this early stage in our spacefaring age, humanity has already begun sending probes that will eventually reach other solar systems, even if that was not their original intention. Five roboti…

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Astronomy Jun 17, 2026

Q&A: Boosting NASA's Swift Observatory to support continued space observation

NASA's "rapid-response" space telescope is slowly falling out of orbit, but a daring mission this summer could allow the Neil Gehrels Swift Observatory to continue scanning the sky for many more ye…

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Astronomy Jun 16, 2026

Webb and Hubble reveal the history of a relic of Milky Way's formation

Researchers using two of humanity's most powerful observatories—NASA's James Webb and Hubble Space Telescopes—have definitively shown that Terzan 5 is not a globular star cluster, as it was onc…

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Jun 16, 2026

A glob and a stellar nursery

Massimo Di Fusco, taken via Chilescope NGC 6727 is a reflection nebula and star-forming region in Corona Australis, part of the larger Corona Australis Molecular Cloud. It is accompanied in this im…

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Human Spaceflight Jun 16, 2026

June 16, 1963: Valentina Tereshkova is the first woman in space

On June 16, 1963, 26-year-old Soviet cosmonaut Valentina Tereshkova made history by becoming the first woman to travel into space. A former factory seamstress, Tereshkova was an accomplished amateu…

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Earth Jun 16, 2026

Dinosaur-killing asteroid created an abode for life

Scientists have new evidence that the dinosaur-killing asteroid that struck Earth created a hydrothermal habitat that lasted for 8 million years.

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Astronomy Essentials Jun 16, 2026

Astro quiz: Test your night sky know-how here!

How well do you know the night sky? Test your know-how of stars, constellations and more with this fun astro quiz. Enjoy!

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Sun Jun 16, 2026

Sun news: Gorgeous eruption! Sun-stuff still awaited

Sun news for June 15, 2026: A beautiful prominence unfurled in the southwest over the past day. Meanwhile, a coronal mass ejection is still on the way to Earth.

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Observing Jun 16, 2026

The Sky Today on Tuesday, June 16: The Moon meets up with Mercury and Jupiter

Looking for a sky event this week? Check out our full Sky This Week column.  June 15: Mercury at greatest eastern elongation The Moon passes 3° north of Mercury at 4 P.M. EDT. Looki…

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