The Giant Squid in the Flying Bat (Sh 2-129 and Ou4)

In this amazing image taken by +Nicolas Kizilian using a William Optics Zenithstar 66 refractor with a WO Flattener 6 and a Moravian G2-8300 you can see Ou4 (The Giant Squid Nebula) within Sh 2-129 (The Flying Bat Nebula). Total exposure time was 25 hours, 20 minutes.

The objects are located in the constellation of Cepheus (, about 2,300 light-years away from Earth. If the estimates of distance and location for Ou4 are correct, its long axis has a length of about 50 light-years.

Sh 2-129, the Flying Bat Nebula (the red nebula in the image) is an emission nebula. Located within this emission nebula is Ou4, the Giant Squid Nebula (the blue-green nebula in the image).

Research suggests that Ou4 is a bipolar outflow ( launched by the triple star system HR8119, consisting of three B-type main-sequence stars (, about 90,000 years ago. The tips of the two lobes are moving at speeds of 83 kilometers/second and 112 kilometers/second. It is however also possible, that Ou4 is a bipolar planetary nebula (see Hen 2-437 here:

More information here:

Paper regarding the Ou4 outflow:

What is an emission nebula?

An emission nebula is a cloud of ionized gas (often by ultraviolet radiation from nearby stars) emitting light of various colors (in case of Hydrogen mostly reddish-pink). More information here:

Image credit: Sh 2-129 and Ou4 +Nicolas Kizilian Used with permission

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#science #astronomy #astrophotograpy #emissionnebula #sh2129 #ou4 #bipolaroutflow #space #bipolarnebula
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