IC 1318, also known as Butterfly Nebula, is an emission nebula and HII region in the constellation Swan. The nebula is about 4900 light years away from Earth and has an extension of 100 light years. IC 1318 is divided into the three parts IC 1318 A (outside the image towards the north), IC 1318 B (upper right of the image) and IC 1318 C (lower left of the image). IC 1318 B and IC 1318 C are separated by the 20 light-years wide dark cloud LDN 88 (at the center).
The nebulosity emits all of its light in isolated emission lines. The most prominent of those is the Hα line, which was exclusively recorded to obtain the image shown above, displayed here in gray tones. At a wavelength of 656 nm, it is located at the red end of the visual spectral range, and cannot be not very well perceived by the human eye during nighttime.
γ Cygni Nebulosity in Hα
IC 1318 - Butterfly Nebula in narrow-band filters, natural colors, which this image is part of.