Photographs made of hundreds of photographs

Astrophotography is not really photography in the moment-in-time sense. Each final image here is a stack of two hundred or more exposures, aligned and averaged to bring signal out from under the noise.

The workflow

1. Two hundred light frames at 20 seconds, tracked.
2. Fifty dark frames at the same temperature, to subtract sensor noise.
3. Fifty flat frames against an even source, to remove vignetting and dust.
4. Stack, align, stretch, and only then think about color.

What the location gives you

Sky darkness is the one variable you cannot fix in software. Four hours under a genuinely dark sky beats forty under a suburban one, and the drive is the cheapest upgrade in the whole discipline.

We shot the same target from the studio car park as a control. The stacked suburban version has roughly a quarter of the usable detail.

Twelve final images, printed at a metre wide, where the stacking finally becomes visible.