Post Processing: Deep Sky Stacker, Pixinsight, Photoshop

At about 4,530 light-years away from Earth, toward the constellation of the Big Dog (Canis Major) Sh2-308 or more popularly known as Dolphin Head Nebula is an H-II region. The nebula was formed about 70,000 years ago by the massive Wolf-Rayet star known as EZ Canis Majoris, (which is the bright one near the center of the nebula), throwing off its outer hydrogen layers, revealing inner layers of heavier elements.
This star is in the brief, pre-supernova phase of its stellar evolution and it has over 20 times the mass of the Sun. Fast stellar winds, blowing at 1,700 km/s (3.8 million mph) from this star, create the bubble-shaped nebula as they sweep up slower moving material from an earlier phase of the star's evolution. The hydrogen composing the nebula is ionised by intense ultraviolet radiation. The nebula is approximately 60 light-years across at its widest point, covers slightly more of the sky than a Full Moon.