Tuesday, Jun 10, 2025

The Squid Nebula is formed from the outflow of gas from the bright star at the centre of the image. The star is a binary, which is probably what caused the nebula to form this unusual shape. The Squid is very large for this type of object, about 50 light years long. The bubble glows in the blue-green OIII light of ionized oxygen, which makes a nice colour contrast to the background red Hydrogen-α nebula Sh2-129. The Squid (Ou4) is very faint, and was only discovered in 2011 by French astro-imager Nicolas Outters, even though the red nebula in the background, SH2-129, was catalogued in the 1950's, and probably known before that.