Star Trail Photograph! (first attempt)

May 24, 2010

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.

We were camping on a lovely site overlooking Robin Hood’s Bay near Whitby (see here for some roundographs taken that day), and I pointed my camera towards the North Star and set my shutter speed to thirty seconds. An hour-long exposure is possible with a film camera but with digital, noise can start to build up (I don’t really understand this properly… I would have thought that noise being random would cancel itself out as the exposure continued, but this apparently isn’t the case). I repeated this twenty-five times, with a brief pause between each exposure while the camera processed each image.

I remembered my tripod but forgot my camera remote control, which meant that I couldn’t lock the shutter on repeat fire. I therefore had to sit next to it for the whole duration pressing the shutter release every thirty seconds. I am a human though and as such am not very good at unvarying repetitive tasks (and was drinking wine and looking through our friend’s telescope at the same time), so was not always very prompt at the button, which is why there are small irregular gaps in the length of the trails.

This type of image is one of the few photographic techniques that still has the capacity to surprise I think. It’s difficult to get a sense of the movement of the stars across the sky, and therefore the movement of the Earth in any other way. That same night we saw Saturn’s rings and the greatest thing that struck me was the speed at which it left the telescope’s field of view: it was possible to actually see movement. That was a strange feeling to actually see the 1000 miles per hour rotation of the planet you’re standing on. This feeling was repeated in a second-hand sort of way the next evening when I put together the exposures I’d taken. The colours were a surprise too: such clearly defined blues and oranges where in the sky they all looked plain white to me.

The next one I try will be more of a landscape. The last shot in the sequence can be used to paint in any foreground objects with a torch in much the same way as the still life light painting from a previous post. Next opportunity I get. I can’t wait :-)

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2 Responses to “Star Trail Photograph! (first attempt)”

  1. Bess said

    Hi LadyCrafthole,

    I’ve always been thinking of doing this one day.

    I followed you here from Flickr. Although i’ve faved some of your photos long time ago (almost 6 mths, i guess), this is the first time i visit your blog.

    Wanna let you know that ur really talented and inspirational. Sorry that i didn’t ask for you permission to use this but I’ve already used it coz i like it very very very much. Don’t know if you recognise this. Would like to share with you. You are really my inspiration.
    http://blog.losinar.com

    • I am so thrilled Bess, that is the loveliest compliment I have ever had, thank you!

      I agree with everything you said about painting: I have never felt so calm and happy in my life as when I have been painting.

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