Full-resolution image: https://app.astrobin.com/i/hsx2ry
In the vicinity of the Cygnus Constellation, we find the Cygnus Loop supernova remnant: the shattered remains of a star that once burned 20 times more massively than our Sun. About 20000 years ago, it detonated as a supernova, briefly outshining Venus and visible in broad daylight from Earth. What remains today is a shockwave still travelling outward at some 1.5 million km/h, colliding with a wall of cooler, denser gas and igniting these filaments as it goes (hydrogen in red, ionised oxygen in blue).
What looks like a thin ring is actually deceptive: the true 3D structure is closer to a bowl, a cavity carved out by the star before it even exploded, into which the blast wave is now crashing. We happen to be looking at it face-on, which is why a solid shape reads to us as a delicate, open loop.
The entire structure spans nearly 3° of sky, about six full moons side by side, and stretches across some 110 light-years of space. Lower right is NGC 6960, the Witch's Broom; upper left, NGC 6995, the Bat Nebula. Between them is Pickering's Triangle, a delicate filamentary wedge of heated gas, discovered by Williamina Fleming but credited, as was common at the time, to her supervisor at Harvard, Edward Pickering.
Framed vertically, the whole structure takes on a different character than in the typical alignment I've shown it in before. It evokes a creature caught mid-scream, its edges torn and trailing into the dark like matted hair.
The people who saw this supernova happen with their own eyes were hunter-gatherers living through the last Ice Age. The world they lived in was almost unrecognisable: sea levels were so low you could walk from Siberia to Alaska across Beringia, and Britain was still joined to mainland Europe. Australia and New Guinea were a single landmass. These people created fine stone blades and tools of bone and ivory, wrapped in tailored clothing sewn from hide and fur. The light captured in tonight's image left the nebula much more recently, around 371 BC, a violent period when Spartan dominance over Thebes ceased for good after the Battle of Leuctra.
Acquisition:
- Shot in Bedfordshire, UK, Bortle 5-6
- RGB (Stars): 1h
- HOO: 16h 5min
Equipment:
- ZWO FF65 + 0.75x reducer
- ZWO EAF
- Altair HyperCam 26M
- Altair 7x2" EFW
- Antlia 3nm Pro SHO filters
- Altair ColourPRO LRGB
- SW EQ6R-Pro
- Astromenia 50/200 Guide Scope + ZWO ASI120MM Mini + IR/UV Cut
PixInsight DSO Processing:
- WBPP
- SPFS
- SPCC
- MGC
- BlurX
- NoiseX
- SyQon Starless
- SetiAstro StarStretch
- GHS
- ColorSaturation
- Curves
- CosmicPhotons ScreenStars
- CosmicPhotons StarReduction
Lightroom Processing:
- Contrast enhancement
- Clarity increase
- Shadows & Highlights
- Vibrance
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