CCD camera with motorised CCD chip

[themos]

I was thinking what if you motorise the CCD chip support board so that you can move the chip in and out of focus without using the telescope focuser. Has anyone heard of such an implementation?

[GordonCopestake]

It's called a motorised focuser isn't it? I'm not sure you would have enough travel if you mounted it within the camera body itself? Might be enough for fine focus though, perhaps computer controlled

[barkis]

If there was an advantage to be gained, then maybe. I can't see one, but then again, others may.

There might be a case for focusing in the normal way, then added electronics could focus the chip with extreme accuracy. In that scenario, the chip movement would only need to be tiny. A bit like adaptive optics really.

Ron.

[themos]

It's called a motorised focuser isn't it? I'm not sure you would have enough travel if you mounted it within the camera body itself? Might be enough for fine focus though, perhaps computer controlled

For fine focus control, a mm will be enough to get you right through to the other side of the critical focus region (which is calculated in Wodaski's book as f²*2.2 microns, where f is the number 5 in a f/5 scope). There is no advantage in moving the entire drawtube. A simple metal strip, slightly bent and under torsion from a driven screw would be enough. Does the situation change when there's a barlow in the way? Is it ok to keep the barlow steady and vary the position of the CCD or must one move the two together as one?