Sh 2-119 – Clamshell Nebula

The nebula displays a complex structure formed by two large shells on either side of 68 Cygni, with emission arcs, delicate filaments, cavities and dark clouds silhouetted against Cygnus’s dense star field. In the image, the hydrogen emissions, represented in golden tones, contrast with the bluish oxygen emissions surrounding 68 Cygni and highlight the effects of its radiation and stellar winds on the interstellar gas.

The image was processed in narrowband using an HOO combination and treated with PixInsight’s NarrowbandNormalization script to balance and enhance the different emissions.

At the centre of the field is the small emission region We 2-245, historically catalogued as PK 87−3.1 and PN G087.4−03.8. Although it was considered a planetary nebula for many years, it is now classified as an H II region. Therefore, no central white dwarf has been identified within it, nor is any reliable associated apparent magnitude known. It appears to be superimposed on the vast expanse of Sh2-119: a small concentration of ionised gas projected against a much larger region of ionised hydrogen. This contrast in scale makes the field particularly interesting.