Pickering’s Triangle, also known as Pickering’s Triangular Wisp, is a fascinating part of the Cygnus Loop, the remains of a supernova explosion that occurred 10 –15 thousand years ago.

It was discovered photographically in 1904 by Williamina Fleming at the Harvard Observatory, although the credit went to the observatory’s director, Edward Charles Pickering – a process that happened all too often then.

The Triangle is a complex network of shimmering filaments and expanding gas clouds, rich in molecular gases that shine in the light of excited hydrogen, oxygen, and sulfur.

This image by one of our members Dean Ashton. HOO. 4 hours total exposure through Ha and OIII narrowband filters. This is known as a HOO pallette where the Ha is assigned to the red channel and OIII data to both the Green and Blue channels.