Astrophotograph of Bode’s Galaxy M81 and Cigar Galaxy M82

This is my astrophotograph of the two large bright galaxies, M81 and M82, commonly known as Bode’s Galaxy and the Cigar Galaxy, respectively. They are gravitationally interacting: The gravity from each dramatically alters the other each time they pass by about every hundred million years. M81 gained its rich spiral arms in the last go round, and M82 developed violent star forming regions and colliding gas clouds. After many more passes over a few billion years, only one galaxy will remain.

This photo was taken on a night with an 85%-illuminated moon. To help combat light pollution, I used my Altair quad-band one-shot colour filter. This seemed somewhat unconventional to me as galaxies are broadband objects, but I’d seen others do it with great success. The filter did an incredible job of blocking out the light pollution, accentuating the star formation regions and nebulae in the spiral arms, and revealing some of the the ionized hydrogen outbursts roughly perpendicular to the disk of M82.

Well lit under the 85%-illuminated moon at 23:30 on 4 April 2020, just after completing a meridian flip.


  • 71× 300-s light frames (Gain 897)
  • 19× dark frames + 32× dark frames from 25 March 2020
  • 60× flat frames
  • 60× dark flat frames


  • Explore Scientific ED 102 mm Apo f/7 refractor
  • Sky-Watcher EQ5 PRO SynScan GOTO equatorial mount
  • Altair Hypercam 294C PRO colour fan-cooled camera
  • Altair quad-band one-shot colour (OSC) 2″ filter
  • Altair 60mm guide scope
  • Altair GPCAM2 AR0130 mono guide camera


  • Sharpcap
  • PHD2
  • DeepSkyStacker
  • Photoshop

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