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Stories from Mt John: Seeing

“Seeing” is one factor that makes a big difference to good planetary photography. Seeing refers to the impact the Earth’s atmosphere has on the telescopes ability to pick up a stable image. In the video below you can see the planet Mars wobbling around. That is the seeing.

Bad seeing means there is lots of wobble - good seeing is a nice steady image. Seeing is hard to predict, except to say that it tends to be worse when the planet is lower in the sky, where there is more atmosphere between the telescope and the planet.

To counteract bad seeing the photos we are taking are composites of thousands of frames, displaying an average of the best frames seen over the course of a few minutes. This technique also reveals details that you wouldn’t pick up with a single image.

The night this little video was taken, the seeing was particularly average.