I went back to my star trail photograph this evening and made up another set of photographs I took, this time pointing at the plough.

This time I altered the levels to bring out as much as I could from the image, and was excited to see I’d got a meteor in it!

I did the same to the previous one to see what I could see, but sadly no meteors. Lots of stars I couldn’t see before though.

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On Saturday night I tried something I have been meaning to do for literally years: a star trail photograph. I love these images, they represent the best thing about photography, which is that far from simply setting down moments as we see them, it has the power to reveal the ordinary world in ways never possible before. Think of a still of a waterfall and how unnatural it must have looked to the first people ever to capture such an image: an imperceptible fraction of a second frozen solid with individual drops crystallized out of the movement blur. This is a perfectly mundane sight to our eyes, despite the fact that before the nineteenth century no human eye in all history ever saw such a thing.

At the opposite end of the spectrum are long exposures.  A 1/20 second exposure produces a fairly natural-looking image of a waterfall: this seems to be about the time-lag our brains work at (hence the number of frames per second in a movie) and anything above starts to look progressively less like the world as we perceive it. Movement creates a cumulative image and averages out randomness, giving moving water a milky-white look as all the random chinks of light blur into each other. [I found myself standing in front of a weir a couple of weeks after posting, so took some photos to illustrate this]

The cumulative nature of long exposures can bring out signals too dim to see with our constantly refreshing visual sense, and it can also combine the effect of continual movement over time. To point a camera at a cloudless night sky for thirty seconds will capture enough light to show up stars, and any exposure much longer than a minute is enough to show them changing apparent position in the sky, which seems astonishingly fast to me.

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