Sharpless 173 is the large faint red nebula in the centre.

18/18/17 x 10 min each of RGB, 30x20min H-Alpha
Camera: Moravian G4 (16803) w Gen II Astrodon RGB and H-Alpha
Scope: Astrophysics AP155EDF Refractor w Focus Boss II
Mount: Paramount MX
Guiding SBIG ST402ME attached to a Borg 60mm guidescope
RGB and H-Alpha processing in PixInsight; Blend of H-Alpha w RGB and save-for-web in PS CC