Ou4: The Giant Squid Nebula.

Difficult to capture , this mysterious, squid-shaped interstellar cloud spans nearly three full moons in planet Earth's sky. Discovered in 2011 by French astro-imager Nicolas Outters , the Squid Nebula's bipolar shape is distinguished here by the telltale blue emission from doubly ionized oxygen atoms. Though apparently surrounded by the reddish hydrogen emission region Sh2-129, the true distance and nature of the Squid Nebula have been difficult to determine. Still, one investigation suggests Ou4 really does lie within Sh2-129 some 2,300 light-years away. Consistent with that scenario, the cosmic squid would represent a spectacular outflow of material driven by a triple system of hot, massive stars, cataloged as HR8119 , seen near the center of the nebula. If so, this truly giant squid nebula would physically be over 50 light-year s across.