Astrophotograph of the Leo Triplet

This is an astrophotograph of the Leo Triplet — a group of three beautiful galaxies inside a field of view spanning about one degree (two full moons). The three galaxies are, in the framing of the image above, NGC 3628 (left), M66 (bottom right) and M65 (top). All three are large spiral galaxies although they don’t look very similar because their galactic disks are tilted at different angles to our line of sight. NGC 3628 is seen edge-on with obscuring dust lanes cutting across the plane of the galaxy, while the disks of M66 and M65 are both inclined enough to just about show off their spiral structure. The warped and inflated disk of NGC 3628, and the drawn out spiral arms of M66 are telltale signs of gravitational interactions between galaxies in this group. The triplet’s estimated distance from earth is about 30 million light-years.

The images in the gallery below show a different framing of the same astrophotograph with a wider field of view, and a plate-solved version with deep sky object shapes and names. The latter image identifies the large number of smaller galaxies also lurking in this field.


  • 62× 300-s light frames
  • 32× dark frames
  • 50× flat frames
  • 50× dark flat frames
  • 50× bias 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 60mm guide scope
  • Altair GPCAM2 AR0130 mono guide camera


  • Sharpcap
  • PHD2
  • DeepSkyStacker
  • Photoshop

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