I remember a grade 10 chemistry lab. where we were asked to describe a flame. A simple experiment where the components or zones of a flame were observed and described.

The blue zone part being the hottest where full combustion occurs and the yellow part of the flame where partial combustion take place at cooler temperature.

In space, NGC6888 reminds me of this simple experiment. The outer envelop of NGC 6888 is blue followed by a red outer layer and a yellow core, following more or less the rules of the grade 10 science experiment.

It is like we are looking down from the tip of a flame towards the blue bottom of the flame. The energy activating all of this energy/colors of NGC6888 is a neutron star within the nebula. That neutron star is like the wick of a candle...

Keep looking up!

Imaging telescopes or lenses: Celestron 9.25

Imaging cameras: ZWO ASI 1600MM-Cooled ASI1600MM Cooled · Orion SSAG

Mounts: Celestron CGX

Guiding telescopes or lenses: Orion 80mm GuideScope Guide scope

Guiding cameras: Orion SSAG

Focal reducers: Celestron Reducer 0,63

Dates:Aug. 31, 2021

Frames: 171x300" (14h 15')

Integration: 14h 15'

Darks: ~30

Flats: ~30

Flat darks: ~30

Avg. Moon age: 23.22 days

Avg. Moon phase: 38.71%

Bortle Dark-Sky Scale: 9.00

Mean FWHM: 2.10