Sh2-129 is located approximately 2,300 light-years from Earth^[1,2] in the constellation Cepheus the King.  Within this large HII region lies the faint, blue-tinted, bipolar outflow^[3] designated Ou4.  Due to its distinctive shape, it is commonly called the Squid Nebula^[2].

Ou4 was discovered in 2011 by amateur astronomer Nicolas Outters^[1,4].  Details of the discovery are presented in Outters' original paper ^[5].  The Squid Nebula's morphology featuring a central, disc-like structure, and two opposing elongated lobes is characteristic of a planetary nebula^[4], and it was originally classified as such.  However, it is now thought to be a bipolar outflow from the bright triple star system at the center of Ou4 (HR 8119)^[3,5].  Given the apparent location of Ou4 in the sky, aligned with the young stellar cluster at the centre of Sh 2-129, it is reasonable to suppose that Ou4 is an out-flow launched some 90,000 years ago from the massive triple star system^[3].

This image was obtained using narrowband and wideband filters.  H-alpha (Ha) data highlights the red emission of ionized hydrogen in Sh2-129, while OIII (doubly ionized oxygen) data reveals the faint bluish structure of Ou4.  Wideband RGB filters were used to image the stars in order to preserve their natural color and enhance the overall aesthetic without distorting stellar hues.