Bubble Galaxy NGC 3521 - Adam Lundie - Eatons Hill Observatory

Bubble Galaxy NGC 3521

Bubble Galaxy NGC 3521 thumbnail
Bubble Galaxy NGC 3521
The large and bright Bubble Galaxy, or NGC 3521, is located in the Leo constellation, which is quite north in the sky for my location. Upon seeing a fantastic test exposure, I could not leave this galaxy alone.

Shooting between trees and through clouds, over 5 nights, the galaxy slowly resolved into the image presented. There are various shells surrounding the galaxy that are most likely from mergers and interactions with other galaxies. The pink regions show star forming nebulae, while the blue regions show young, blue stars.

Image Integration:

  • 51x 240s Luminance
  • 31x 240s Red
  • 27x 240s Green
  • 26x 240s Blue

Total exposure 9 hours.


  • Celestron 11" EdgeHD
  • SkyWatcher EQ8 Pro Mount
  • QSI 683-ws8 Camera @ -15°C
  • Astronomik Typ2 Luminance, Deep Sky RGB filters
  • Starlight Xpress Lodestar X2 Autoguider
  • Starlight Xpress Active Optics
  • Innovations Foresight On Axis Guider


  • Imaged over five nights, some cloud, high humidity. Orange zone in Brisbane, Australia. (Bortle 7)


  • Planning & camera alignment with The SkyX Pro
  • Captured with AstroArt 6
  • Guiding with PHD2 + PHD_Dither
  • CCDInspector: Image analysis & rejection
  • CCDStack 2+: Calibrate, align, stack.
  • PixInsight: Rotate, crop, deconvolution, reduce noise, shrink stars, stretch, HDR median transform, local histogram equalistion, LRGB combination, curves, saturation.
  • Photoshop CC: Complex mask generation, caption, repair chromatic aberration on larger stars, convert to .png.