Emerging from the depths of interstellar space, Ou4, known as the Giant Squid Nebula, is a rare and enigmatic structure drifting through the constellation Cepheus. This immense bipolar nebula spans nearly 50 light-years, with its ghostly tendrils of ionized oxygen stretching across the cosmos like the outstretched arms of a deep-sea leviathan.

Unlike typical emission nebulae, Ou4's origin remains a subject of scientific investigation. Initially believed to be a planetary nebula, it is now thought to be a massive outflow of gas ejected by the bright, central triple-star system HR 8119, which bathes the nebula in high-energy radiation, causing it to glow in a striking blue hue. Its faint, wispy structure is best revealed through deep imaging in the oxygen-III (OIII) wavelength, making this HOO capture an ideal palette for showcasing its elusive form.

Surrounding the Giant Squid is the broader Sh2-129, the Flying Bat Nebula, a hydrogen-rich emission nebula that provides a contrasting red backdrop, further emphasizing Ou4’s ethereal glow. The juxtaposition of these two nebulae hints at a complex interplay of stellar winds, radiation, and shock waves sculpting the interstellar medium.

Captured from Saint-Saturnin, France, this deep exposure reveals the extraordinary detail and delicate structures of one of the most intriguing and mysterious objects in the night sky—a spectral giant adrift in the cosmic ocean.

The Squid Nebula, also known as Sh2-129 or Ou4, is one of the most enigmatic and striking deep-sky objects. Located in the constellation Cepheus, this faint emission nebula spans an astonishing three degrees of the sky—roughly six times the diameter of the full moon. It was first discovered in 2011 by French astrophotographer Nicolas Outters.

What makes the Squid Nebula so extraordinary is its ghostly, bipolar shape, which appears embedded within the larger Sh2-129 region, known as the Flying Bat Nebula. The nebula glows predominantly in the OIII wavelength, giving it a bluish hue that contrasts dramatically against the surrounding H-alpha emission of Sh2-129.

Astrophysicists speculate that Ou4 may represent an enormous outflow of material ejected from a triple star system at its center, potentially linked to a massive stellar wind or an ancient supernova event. However, its true origins remain a subject of ongoing study.

Image Description and Details:

A nebula, Ou4, that I find very pretty so at the beginning of July, I started to photograph it. It is carried out in hoorvb. until October I got 113 hours of exposure in order to prepare for this image.

OIII 200X900S

HA 260X600S

RVB 240X300S



Copyright Information: Rémi Méré