I've already done the Helix Nebula in natural colour, so I've imaged it again in narrowband. Lots of H-alpha and Oxygen-III, but barely any Sulfur-II.
- 34x 1200s H-alpha 6nm
- 33x 1200s SII 6nm
- 17x 1200s OIII 6nm
Total exposure 28 hours.
Shot with a QSI 683-ws8 Camera @ -15° though a Skywatcher Black Diamond ED120 on an EQ8 mount
Larger resolution here