Canon T3i First Light

I have a fine old camera now: a Canon T3i DSLR circa 2011. The only lense I have is the 18mm-55mm kit lens(30-80mm equivalent) so nothing like the Nikon’s 2000mm equivalent but the sensor in the canon is 22mm by 14 – sixteen times the surface area of the Nikon’s!  The shots below were taken toward the west with the big dipper high in the sky.  The pale one is 30 seconds at f3.5 ISO 800, the darker one ISO 100. The third shot is the paler one with the contrast boosted.

They’re all out of focus but they show way more stars than my poor old eyes can see so that’s a good start.
Two interesting things I learned doing this:

  • Cranking the focus ring all the way does not focus to infinity. You have to actually focus by eye. This make sense in retrospect because that lens could go on many cameras and the distance from lens to focal plane is going to be a bit different.
  • The contrast algorithms work to increase the pixel rgb values above 128 and reduce those below it. The further they are away from the midpoint the more they move. There’s a good explanation here.

At the same time I noticed the space station going by and grabbed a 10 second exposure of that.  That’s also out of focus but kind of pretty after i messed with the contrast. The bright star is Vega by the way.
19-05-19 ISS 3327


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