One of the joys of wide-angle astronomical imaging is that once the camera, tracking device and intervalometer start their work, they are quite happy running unattended. This leaves me to sit and watch the sky wheeling overhead, usually with mouth open in awe at the naked-eye view of a dark sky. Or if I had a van full of gear, I could set up a scope for viewing, but I'm normally not that organized. The other night, while imaging the "ghost comet" and current Comet Lovejoy, I had another impromptu experiment to try...
Optics Picture of the Day - an always interesting site on atmospheric phenomena, in a recent post on "Time Varying Lights". But I've seen this done even earlier. Imagine hand-holding a telephoto shot of a star for a several second exposure. The results can be interesting, as shown in the link and also here at left. The star Canopus, only a few degrees off the southern horizon, was twinkling moderately, and in its long path through the atmosphere, different colors are refracted differently, resulting in a constantly-changing, almost psychedelic light show. The short time exposure, with the hand-held wiggles added record the changing intensity and colors. I braced myself against the open door of the van to provide a little extra "bounciness" to the image. I suspect that I could have done a better job of hand-holding otherwise. If you use an image-stabilized lens, make sure you turn that feature off! These shots were taken with the Canon 70-200 lens set to the maximum.
This was a fun little 10 minute project to do while my other camera was busy exposing. Would I do it again - absolutely! Perhaps even a little more focal length would show scintillation and color even better. I've got a little 80mm Meade scope that might be perfect! Go ahead and try it!
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