Pickering's Triangle

This triangle of glowing filaments belongs to the same cloud of debris as the Veil Nebula: the remains of a star that exploded thousands of years ago, in the constellation of Cygnus. But it carries a name of its own, for a very human reason.

It is called Pickering's Triangle. Yet it was not Edward Pickering who discovered it: it was Williamina Fleming, in 1904, while examining photographic plates. Fleming was one of the “Harvard Computers”, women hired to pore over the observatory's data for a pittance. First taken on as the housemaid of Pickering, the director, she became one of the finest astronomers of her time. But as was the custom of the day, the discovery was credited to her boss, and it is his name that stuck.

Today, some set the record straight by calling it Fleming's Triangle. Whatever the name, these delicate wisps are a shard of the same shock wave that, for thousands of years, has been racing through space and lighting up the gas in its path.

A word about the colours: the image was taken through a filter that keeps only the light of two gases. The red-orange is hydrogen; the blue is oxygen. This stays fairly close to what those gases truly emit; the tones were simply accentuated in processing to bring out the filaments.