Very faint but also very large, a giant Squid Nebula cataloged as Ou4, and Sh2-129 also known as the Flying Bat Nebula, are both in this scene toward the royal constellation Cepheus.
Composed with a total of 17 hours of dual narrowband data, the field of view is almost 3 degrees or 6 Full Moons across.
Discovered in 2011 by French astro-imager
Nicolas Outters, the Squid Nebula's alluring
bipolar shape is distinguished here by the telltale blue
emission from doubly ionized oxygen atoms. Though apparently completely surrounded by the reddish hydrogen emission region Sh2-129, the true distance and nature of the Squid Nebula have been difficult to determine. Still, a
recent investigation suggests Ou4 really does lie
within Sh2-129 some 2,300 light-years away. Consistent with that scenario, Ou4 would represent a spectacular outflow driven by HR8119, a
triple system of hot, massive stars seen near the center of the nebula. If so, the truly giant
Squid Nebula would physically be nearly 50 light-years across.
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