Sharpless 204 (Sh2-204) is a broad, faint emission nebula in Cepheus, forming part of the larger Hα complex together with Sh2-205 and Sh2-206. Though it spans a large region of sky, it lies hidden behind a dense veil of foreground stars and interstellar dust, making its delicate structures easy to overlook:

📷 rgb.jpgThis image reveals the nebula’s striking mix of emission lines: a comparable, strong Hα and SII signal creates the deep red filaments that trace the outer edges of the ionized bubble, while the OIII component is far more elusive and appears only as a faint bluish core. The dark clouds that wind through the field add a sculptural contrast, standing in silhouette against the glowing gas.

Careful processing was required to bring out the faint OIII glow and to merge the narrowband data with broadband exposures that capture the full richness of dust and stars. The result highlights both the energetic ionized regions and the quiet complexity of the surrounding interstellar medium in this often-overlooked corner of the Sharpless catalog.