Original poster: Jim Lux <jimlux@xxxxxxxxxxxxx> At 09:23 AM 10/2/2006, Tesla list wrote:
Original poster: "Peter Terren" <pterren@xxxxxxxxxxxx>Well, I've taken well over 500 photos today and have whittled them down to 100 for a closer look.There is a little mirror aberration giving ghosting due to flex of the mirror in the support giving horizontal displacement. Seemed to get worse during the day so needs a new design with no stress and epoxied in place. Possibly a proper mirror.
polished solid metal is probably your friend. You could have a machinist make a suitably balanced mirror with an integral shaft, and then spend some of your copious free time <grin> with some lapping compound bringing it to a shiny finish.
Actually, though, I have spent a few hours in the evening brass lapping waveguide flanges to a mirror finish in front of the television. It doesn't take long to get from the "vertical mill" finish to an actual mirror.
The "big boys" in the rotating mirror camera business use things like electric or air powered die grinders to spin them. 10,000 RPM is easy, especially with an air turbine. Standard inexpensive air tool die grinders are cheap and very, very fast.
The other thing that they do is run the mirror in a partially evacuated housing, or one filled with helium (which has very low density and viscosity, so low drag). While this sounds totally impractical, it's actually not all that hard to arrange, especially with a digital camera, which doesn't need to have film changes.