Astrophotograph of Bode’s Galaxy M81

Three clear nights in a row⁠—that hasn’t happened for about 10 months! I thought I would shoot a galaxy for a change as I’ve been shooting nebulae in the last few sessions.

This is my astrophotograph of Bode’s galaxy (as it was first discovered by Johann Bode in 1774). It is a large and relatively bright spiral galaxy about 12 million light-years away (so about 80 of our own galaxy, the Milky Way, could fit side-by-side in this gap). It is about 90000 light years in diameter, so almost half the size of the Milky Way.

The weirdly shaped triangular stars, each with 3 shadows that look a bit like ‘inverted lighthouses’, are an optical artefact caused by the telescope’s lens spacers. I’m working on fixing that, but the job is a little scary and so I’m working up to it. Basically, my new telescope shipped with shipping screws installed to prevent the optics from moving during shipping. Sometimes these screws are slightly tight and pinched optics are noticed during astrophotography. It’s a simple job to remove the dew shield and loosen the nine set screws, but there’s a risk of decentering/misalignment.


  • 63× 130-s light frames
  • 30× dark frames
  • 32× flat frames
  • 36× dark flat frames
  • 103× bias frames


  • Explore Scientific ED 102 mm apo f/7 refractor
  • Sky-Watcher EQ5 PRO SynScan GOTO equatorial mount
  • Altair GPCAM3 290C colour camera (with UVIR window fitted)
  • Altair 60mm guide scope
  • Altair GPCAM2 AR0130 mono guide camera


  • SharpCap Pro
  • PHD2
  • DeepSkyStacker
  • Photoshop

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