This portion of the Cygnus Loop Supernova remnant, situated between the Veil and Witch's Broom Nebulae, is commonly known as Pickering's Triangle. However, it was one of his employees at Harvard College Observatory, Willamina Fleming, who actually discovered this nebula while examining a photographic plate. However, as was the custom of the time, the credit went to Pickering. Pickering was a progressive man, employing many women at the observatory, several of whom made major contributions to astronomy, including Annie Jump Cannon, Antonia Maury, and Cecilia Payne. But it is high time Fleming received at least partial credit for her triangle, so I am re-naming it Picker-Flem-ing's Triangle Fleming also discovered the Horsehead Nebula and the first white dwarf, 40 Eridani B.
Image Data:
Telescope/Mount: Celestron Compustar C14
Camera: SBIG STL 11000M with Baader Planetarium Ha, R, G, and B filters.
Adaptive Optics: SBIG AO-L at 8Hz
Location: Pommier Observatory, Portland, OR, USA
Dates: 2017-07-17 through 2019-08-20
Exposures: Ha:R:G:B = 690:210:190:225 minutes = 21 hours, 55 minutes total exposure.
See additional astrophotographs at www.rodpommier.com