The Pickering's triangle, which was discovered on Jan 13, 1905 by Williamina Fleming, as well as their neighbors are part of the veil nebula, a cloud of heated and ionized gas and dust in the constellation Cygnus. It constitutes the visible portions of the Cygnus Loop a supernova remnant. The source supernova was a star 20 times more massive than the Sun which exploded between 10,000 and 20,000 years ago (Wikipedia).

The Fleming's triangular wisp was an extremely challenging target prior to the availability of narrow band filters, now it has become a very accessible classic. Yet, capturing all the very fine details and signals of this fascinating deep sky object remains a challenge. I therefore decided to shoot 600 sec subs to capture as much signal as I could. As for my previous images, I only retained the subs with the best HFR values to maximize the quality of the end result. Down to practice, I eliminated >40% of the subs.

During the processing, I started with the now classical solution to generate a starless version and added the RGB stars on top. To my surprise, when I looked at the SL Ha image generated with SXT, I noticed that several details present in the original Ha image were lost. I thus generated a second SL Ha image using StarnetV2, which was ok but also not perfect, and combined both to have the closest image to the original Ha. For OIII this problem was less noticeable.

With respect to the color balance, I generated a pure RGB version of the nebula, calibrated using SPCC, then deleted the stars with Starnet. I then used this result as a basis to balance the colors of the HOO version, so to have a representative color palette as compared to a classical RGB version.

From the deconvolution angle, I generated versions without BXT, with BXT050 and BXT070. In the BXT070 version, I noticed non-natural signals, thus I opted for a mild sharpening with BXT050.

At last, I decided to focus on the Pickering Triangle and to provide as a "A" version the entire framing containing NGC 6979 and 6974.

As usual don't hesitate to provide input on the image.

CS,

Nicola