Tuesday, October 02, 2007

Night moves

There's a lot of movement in this photograph, if you look carefully.

The picture was taken at 1:16 a.m. The exposure was 30 seconds at f5. The long exposure allowed the moonlight to illuminate the grass and clouds. The moving clouds were blurred in the long exposure, as were the leaves on the top of the tree at right.

The long exposure and the rotation of the earth also caused the stars to trail; they are elongated instead of being points. An even longer exposure would leave longer streaks or trails as the stars moved across the sky.

The constellation Orion is visible at the top of the frame. Orion is a winter constellation that can be seen late at night (or early in the morning) in the fall. The reason I was out taking pictures was that I received an email that auroras might be visible in mid- to low-latitudes. I did not see any.

1 comment:

erik said...

great shot tom...i love night shots. especially the long 30 minute type that give really long star trains...

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