This is my astrophotograph of the Eastern Veil Nebula NGC 6992. It is one of the visible parts of the Cygnus Loop, a large supernova remnant in the constellation Cygnus (some other parts of the loop are not visible to the human eye, but emit in radio, infra red and X-ray). Another visible part of the Veil Nebula is known as the Witch’s Broom Nebula, which I photographed in September 2019. The source star of the supernova exploded between 10 and 20 thousand years ago and its remnants have been expanding ever since. The Veil Nebula is currently expanding at about 1.5 million kilometers per hour and now spans an apparent diameter of about 6 full Moons.
The nebula appears to have a structure of red and blue intertwining filaments. The red emission comes from hydrogen atoms, and the blue emission from oxygen atoms. The filament-like structure is due to the expanding shock wave of hot gases which forms a thin shell (with a thickness roughly equal to the distance between Earth and Pluto). This shell can only be seen edge-on, thus giving the appearance of a filament. Undulations in the shell surface give the impression of multiple intertwining filaments.
- 22× 265-s light frames (Gain 900)
- Full use of calibration frames (darks, flats and dark flats)
- Explore Scientific ED 102 mm Apo f/7 refractor
- Sky-Watcher EQ5 PRO SynScan GOTO equatorial mount
- Altair Hypercam 294C PRO colour fan-cooled camera
- Revelation Adjustable Field Flattener
- Altair quad-band one-shot colour (OSC) 2″ filter
- Altair 60mm guide scope
- Altair GPCAM2 AR0130 mono guide camera