I mentioned in an earlier post that there were some interesting scenes captured with a DSLR while waiting for much longer exposures on the telescope. Here is an example; a shot of a deep canyon with the Big Dipper overhead. At first glance, this looks like a fairly ordinary daytime photograph – that somehow has stars showing! In fact, this was shot late at night, after the Moon had set. Except for a small area on the right edge of the rim, there is nothing but starlight (and a bit of light from distant cities) illuminating the scene. That bright part on the right edge is light leaking from some campers far out of the frame. This is facing northeast, the only part of the local horizon that doesn’t have a significant “light dome” from a distant city. The pink horizontal lines near the horizon are distant airplanes with flashing lights.
This is a mosaic of 2 frames, each single exposures of 10 seconds, shot with a Canon 6D and a 24mm f/1.4 lens (stopped down to f/2.4) at ISO 6400. I put this together quickly from last night’s outing just to show you what I was talking about. I didn’t use any special software tools to make the mosaic. I intentionally framed the shots to have overlap at the horizon, an area that has very little detail, so even a crude composite of the 2 frames looks pretty natural.
To take this picture (and many more like it), the camera was on a tripod standing right on the edge of the canyon, as was I. In complete darkness. A little unnerving, but well worth it, I think!