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  ✦

NuSTAR X-Ray Telescope Launched

June 19, 2012
© Fiona Harrison et al., Caltech, NASA
What's left after a star explodes? To help find out, NASA launched the Nuclear Spectroscopic Telescope Array (NuSTAR) satellite into Earth orbit last week. NuSTAR's ability to focus hard X-rays emitted from the nuclei of atoms will be used, among other things, to inspect the surroundings of supernova remnants so as to better understand why these supernovas occurred, what types of objects resulted, and what mechanisms make their surroundings glow so hot. NuSTAR will also give humanity unprecedented looks at the hot corona of our Sun, hot gasses in clusters of galaxies, and the supermassive black hole in the center of our Galaxy. Pictured above is an artist's illustration depicting how NuSTAR works. X-rays similar to those used in your dentist's office enter the telescope on the right and skip off two sets of parallel mirrors that focus them onto the detectors on the left. A long but low-weight mast separates the two, and the whole thing is powered by solar panels on the upper left. Part of the excitement involving NuSTAR is not only what things it is expected to see, but by looking at the universe in a new way, what things that are completely unknown that might be discovered. NuSTAR has a planned two year lifetime. Slide Set (ASOW): NuSTAR by PI Fiona Harrison

Customized Star Charts Coming 1st Quarter 2027

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✦  EarthSky  ·  Astronomy.com  ·  Phys.org  ✦
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