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Anyone who enjoys looking at star maps from long ago soon realizes that the concept of “constellations” was applied rather loosely, depending on the whims of each cartographer. And over time some constellations were proposed but never caught on — or were later abandoned. (Check out Bob King’s amusing look at some of these.)
It wasn’t until 1922 that the International Astronomical Union agreed on a list of 88 constellations, drawn from Western traditions, to cover the entire celestial sphere. Six years later the IAU adopted precise boundaries for each one that were published in 1930.
These days, even seasoned starwatchers would be hard pressed to name most of the constellations, in part because those of us at mid-northern latitudes can’t see the ones in the far southern sky and vice versa. For example, someone living at latitude 40° north has no chance of seeing any of the night sky south of declination –50° (ignoring atmospheric refraction). This geometry renders 14 constellations completely hidden and another 15 only partly in view throughout the year.
But that shouldn’t stop you from being curious about both the well- and lesser-known constellations that fill the sky. And now you can explore them any time, thanks to a new online resource launched this week by the National Science Foundation’s NOIRLab in partnership with the European Space Agency.
NOIRLab / NSF / Eckhard Slawik
The 88 Constellations Project brings together several resources. Most impressive is a complete set of downloadable high-resolution images acquired by German astrophotographer Eckhard Slawik. His images, recorded on film, combine exposures with and without a diffusing filter to allow the stars’ colors to shine through — a technique pioneered by the late Akira Fujii. Slawik has also combined his individual frames into an all-sky image that lets you navigate around and zoom in on any location.
The entry for each constellation includes a comprehensive description and its historic origins, as well as the stick figures and finder charts (created in partnership with Sky & Telescope). Also available are images and descriptions of each constellation’s most prominent deep-sky objects.
As you explore what’s available at NOIRLab’s 88 Constellations Project, don’t forget that other websites also offer excellent introductions to the sky. One example is Iacopo Sassarin’s theskylive.com, which lets you know whether a given constellation is currently visible from your location. (Do you have others to suggest? Then add a comment below with the links.)
And of course, don’t forget Sky & Telescope’s interactive sky chart, which you can customize for any location, date, and time.