#ic 5146

The Cocoon Nebula (IC 5146)

On the left side of this image.

If you use a wide-field eyepiece, also look for dark nebula Barnard 168, which stretches to the right.

07/23/2026

IC 5146

IC 5146 - the Cocoon Nebula (HaRGB)

An especially fun target to shoot, because it's a combination emission and reflection nebula. The red in its center is ionized hydrogen, which emits a deep red glow, but the areas around the nebula with fewer stars are filled with dust, which reflects nearby starlight to produce the pale blue glow at the nebula's apparent edges.

Shot at 1600mm with a 200mm RC telescope and a ZWO ASI533MM Pro. 2h of Ha integrated exposure time, plus 1h each of RGB data.

IC-5146 has the colloquial name “The Cocoon Nebula” because of the round and fuzzy shape. It is situated nearby in our Milky Way galaxy, at a distance of only 4,000 light years. As suggested by its proximity and tight round appearance, it is only 15 light years in diameter.

This is a very active stellar nursery, and surveys by space telescopes have identified hundreds of hot young stars within the nebula.

It is a beautiful target for amateur astrophotographers, as the apparent size is convenient for most backyard telescopes and the rich red colour is certainly rewarding. It is the goal of astrophotographers to render the streaks and ripples at the centre, as well as the faint pale cloud surrounding it. Because of the distinctive location, shape and colour, it is sometimes called “The Ruby Jewel of Cygnus”.

I photographed the Cocoon Nebula from my garden in Strasbourg France on a single night in July 2024. This is an ensemble of 70 photos, where each was a 3 minute exposure (3.5 hours of photography).

More about the Cocoon Nebula: