The Iris Nebula

The Iris Nebula is a reflection nebula 1,300 light years away, illuminated by a partially embedded star (SAO 19158) which is 10X the size of our Sun. The region is 6 light years across in total.

Iris Nebula / Caldwell 4

You can really see how the light from the central cluster illuminates the dust and scatters within it. I love the vast dark, dusty regions around the edges, where the starlight doesn’t penetrate. These are amongst the coldest places in our Universe; dark, shielded locations where gas and dust collect for eons before being awoken by changes in temperature and density from the galaxy beyond.

The Iris Nebula was first noted by William Herschel, but is also known as Caldwell 4. Herschel observed this through his telescope in the 18th Century, whereas the data for my image was acquired remotely via DeepSkyWest in New Mexico, processed with PixInsight, and tweaked in Lightroom. More technical info at


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