Bowie’s Bolt: Asterism or constellation?

After David Bowie’s passing, the media reported that a new “constellation” was created to honour the rock star. Can it really be?

Constellations vs. Asterisms

An asterism is simply a celestial figure formed by connecting stars together. When we look at the heavens, geometric patterns stand out among the hundreds of twinkling points that dot the night: A bright triangle adorns the summer sky; a huge hexagon illuminates winter evenings; and in spring, there’s a sickle rising in the east.

Star patterns can also be more complex. With some imagination, we can picture people, animals and objects… like our ancestors did when they created the “classical constellations” to immortalize the various characters of their mythologies in the heavens. For them, the starry sky was an illustrated account of legendary heroes and their deeds—a celestial storybook.

But the early constellations also served a greater purpose: They helped identify and track important stars that were used as navigational and agricultural guides. Ancient explorers and traders set their course according to the stars, and farmers planted and harvested crops according to the rising and setting of certain bright stars.

Each culture had its own perspective and references, though “western” culture, anchored in Greco-Roman, North African and Mesopotamian traditions, provided the standard representation of the celestial sphere that’s used globally today.

Constellations then and now

In his 2^nd century Almagest, Claudius Ptolemaeus (Ptolemy) catalogued the position of the thousand brightest stars, located in 48 constellations. Then, nearly 1500 years later, the authors of the first printed star atlases created new ones to fill the voids between the original 48. But their number, shapes and sizes varied from atlas to atlas: Some never caught on and were quickly abandoned. Meanwhile, the exploration of the southern hemisphere in the 17^th and 18^th century spurred the creation of about two dozen more constellations.

Clearly, uniformity was needed… In the 1920’s the International Astronomical Union entrusted Belgian astronomer, Eugène Delporte, with the task of ensuring that each square degree of sky would fall within a constellation. His publication, Délimitation scientifique des constellations (1930), firmly fixed the number of constellations and their boundaries at 88, and it serves as the absolute reference today.

In the modern sense, a constellation includes not only the bright stars that form its asterism, but also the surrounding region of sky up to its neighbours’ boundaries. The 88 official constellations fit together like the pieces of a spherical jigsaw puzzle. New constellations can’t be created, and existing ones can’t be modified… at least, not officially!

But nothing prevents us from creating our own asterisms! Amateur astronomers often do it, whether to find their way among the stars with the naked eye, or to “star-hop” when using a telescope. And that includes “Bowie’s Bolt”—the asterism inspired by the rock icon’s stage make-up and proposed by Belgian public observatory Mira at the behest of a Brussels radio station. But in fact, “Bowie’s Bolt” can only be seen entirely from the southern hemisphere, and some of the asterism’s seven stars are, in fact, too faint to view with the naked eye…

In collaboration with Louie Bernstein.