Trifid Nebula in HaLRGB - Adam Lundie - Eatons Hill Observatory

Trifid Nebula in HaLRGB

Trifid Nebula in HaLRGB thumbnail
Trifid Nebula in HaLRGB
Almost everyone has a go at imaging the Trifid nebula, which is composed of 3 different type of nebulae; emission, reflection, and absorption. When I noticed some faint red glow in the background, I decided to try integrating some long hydrogen emission line frames to see if I could get any structure out of it. I'm quite happy with the resulting background structures!


  • 31x 600s Luminance bin1x1 + 15 flat + 50x dark + 120x bias
  • 19x 300s Red bin2x2 + 12 flat + 50x dark + 120x bias
  • 19x 300s Green bin2x2 + 12 flat + 50x dark + 120x bias
  • 19x 300s Blue bin2x2 + 12 flat + 50x dark + 120x bias
  • 31x 1200s H-alpha bin1x1 + 20 flat + 50x dark + 120x bias

Total exposure 20 hours 15 minutes.


  • Skywatcher Black Diamond ED120
  • SkyWatcher EQ8 Pro Mount
  • QSI 683-ws8 Camera @ -15C
  • Astronomik Typ 2c LRGB, 6nm Ha filters
  • Starlight Xpress Lodestar X2 Autoguider
  • Innovations Foresight On Axis Guider
  • Starlight Instruments Focus Boss II


  • Orange zone in Brisbane, Australia. (Bortle 7)
  • Imaged over 4 nights, new moon.


  • Planning & camera alignment with Aladin 9
  • Captured with AstroArt 6
  • Guiding with PHD2 + PHD_Dither
  • FocusLock live focusing
  • CCDInspector: Image analysis & rejection
  • CCDStack 2+: Calibrate, align, stack, deconvolution, combine RGB.
  • Photoshop CC: Merge Lum+Ha as luminance, curves, high pass filter, merge HaL+RGB, minimum filter, color adjustment, saturation.