DSLR Astrophotography

Digital SLR cameras make surprisingly good astrophotography cameras on bright objects. Good sensitivity, low noise and a convenient form factor make these camera a good choice for shooting the night sky.

One useful modification to the camera is removing the standard IR cutoff filter present in cameras and replacing it with a filter that is tuned to let in more of the red. The new filter should allow light at 656nm, what astronomers call hydrogen alpha, or Hα, the light emitted by neutral hydrogen atoms, the most common element in our universe. This is the red glow that makes the emission nebulae so colorful. An astrophotographer can do the filter change themselves, send it to a specialist who can do the work, or buy an already “modded” camera. Canon has produced two special models specifically for the astrophotography market, the EOS 20Da and 60Da, with this special filter.

Below, one can see the results of using modified, and unmodified cameras and relatively small telescopes…