M17 - Swan Nebula
From the author of Sizing Up The Universe
22:04 EDT Sept 10, 2017.
Starlight Express Trius-SX-694 on 10" RC at f/9.
Hα = 50 min, O-III = 50 min (in guided 1-minute and 5-minute subexposures).
Richardson-Lucy deconv and Gamma stretch.
22:25 EDT Aug 8, 2007.
Starlight Express SXV-H9 on Takahashi FSQ106 at f/5.
Hα = 65 min, O-III = 30 min (in guided 5-minute subexposures).
Gamma stretch.