A wave of Ionised Oxygen (O3) streaks across the background clouds of Hydrogen (Ha).
It is believed to result from a powerful explosion of a star some 11,000 -12,000 years ago.
The shock waves shown in the image as blue from oxygen emission and red from hydrogen emission have been expanding ever since.
The huge star at the top left is Gamma Velorum, a quadruple star system in the constellation Vela.
At a combined magnitude +1.7, it is one of the brightest stars in the night sky, and contains by far the closest and brightest Wolf-Rayet star.
It has the traditional Arab name Suhail al Muhlif.
(wiki)
The open cluster at the centre is Collinder 173.
Image & processing inspired by
Marco Lorenzi 
Large Image
HERE
SV70t Refractor on TAK NJP mount - QSI 683 wsg8 camera.
Ha 240mins, O3 540mins, RGB 30mins ea.
Taken over 3 nights from from Burwood, Suburban Melbourne.
