The Veil Nebula - West (NGC 6990) is a cloud of heated and ionized gas and dust in the constellation Cygnus, the Swan.
It constitutes the visible portions of the Cygnus Loop, a large but relatively faint supernova remnant.
The source supernova exploded circa 3,000 BC to 6,000 BC, and the remnants have since expanded to cover an area roughly 3 degrees in diameter (about 6 times the diameter of the full moon).
The distance to the nebula is not precisely known, but is estimated to be approximately 2,100 light-years away.
The wisps of gas are all that remain of what was once a star 20 times more massive than our sun.
The fast-moving blast wave from the ancient explosion is plowing into a wall of cool, denser interstellar gas, emitting light.
The nebula lies along the edge of a large bubble of low-density gas which was blown into space by the dying star prior to its self-detonation.
The star shown in the centre is the 4th magnitude star 52 Cyg.
The full nebula is shown as follows:
Equipment:
- Vixen AX103S 103mm f/8.0 ED Apochromatic Refractor telescope.
- Avalon Linear Fast Reverse Mount.
- QSI 683 CCD camera, Kodak KAF-8300 8.3 mega-pixel sensor cooled to -25 °C.
- Astronomik L-RGB, Astrodon 5nm Ha and Astrodon 3nm Oiii filters.
Image exposure (4+ hours in total):
14 x 20min Ha images.
