Abstract: Fleming’s Triangle, also known as Fleming’s Triangular Wisp, is a delicate and lesser-known filament within the Veil Nebula, a sprawling supernova remnant in the constellation Cygnus. It’s often known as Pickering’s Triangle, but the true discoverer was Williamina Fleming, a pioneering astronomer at the Harvard College Observatory who identified it in 1904 while examining photographic plates.

At the time, the credit was given to Edward Charles Pickering, the observatory’s director, following the conventions of the time.

Pickering wasn’t the one who spotted it—but his name stuck. He was a pioneering American astronomer known for leading the Harvard Observatory and for hiring a team of women, later called the “Harvard Computers,” to catalog and classify stars. Fleming, originally hired as Pickering’s housemaid, became one of the most accomplished members of that team. She also discovered the Horsehead Nebula and helped develop a system for classifying stellar spectra.

So while Pickering’s Triangle bears his name, it’s really Fleming’s legacy that shines through the wispy filaments of that supernova remnant. Some even refer to it as Fleming’s Triangular Wisp in her honor, like me.

So hooray for Women!

Key Features

• Location: Central region of the Veil Nebula, between the brighter Eastern and Western arcs

• Coordinates: RA 20h 48m 31s Dec +31º 28′ 16″

• Size: Roughly 43×20 arcminutes, spanning about 30 light-years across

• Distance from Earth: ~2,100 to 2,400 light-years

• Composition: Filaments of ionized hydrogen (red) and oxygen (blue), shaped by shock waves from the ancient supernova

Co-Pilot AI comments on my uploaded photo

That’s a beautiful capture, Andy! The delicate interplay of yellow and blue filaments really highlights the complexity of the shock-front interactions in Fleming’s Triangle. You’ve nailed the ghostly textures that make this region so captivating—almost like celestial embroidery stitched into the dark fabric of space.

💡 A Few Highlights in Your Image

• Wispy filaments: That shimmering lace of ionized gases (especially [O III] in blue and Hα in yellow) echoes the turbulence from the supernova blast thousands of years ago.

• Depth of field: The layering of stars behind and within the filament network adds a rich dimensionality, drawing the eye from edge to core.

• Color balance: Your palette choices emphasize the energy of the shock fronts without overpowering the subtler threads—a great artistic and technical decision.

If you’re open to it, I could help you refine star reduction or enhance contrast along the filament edges using PixelMath or subtle histogram tweaks in PixInsight. Or if you’re planning a multi-panel mosaic of the Veil, we could lay out your next targets—like the Witch’s Broom or NGC 6960. Let me know how you'd like to build on this beauty!