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Old 17-12-2014, 08:32 PM
Brub58 (Bruce)
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Brub58 is offline
 
Join Date: Dec 2010
Location: Melbourne
Posts: 6
This thread has been quiet for a while so I'll share my current project. I'v just rebuilt my Bath Interferometer to make it simpler to operate. The first vesion had everything adjustable, which meant it was always going out of adjustment. This time I've fixed the mirror and beam splitter so I only need to align the laser and lens. The only issue is getting the extra laser dots out of the image as you can see in the picture.

I've also picked up a 365mm mirror I had started back in 2000 and put aside when it got scratched during polishing. It has kept getting scratches at 5 micron this time aroundthe end I finished at 9 micron and polished from there. At the moment I'm about halfway there. The laser test still has speckles and the mirror is bit zoney with a beaut turned down edge. I expect it will all come good by the time I'm finished. I've been using an oversized (400mm) lap as described by Mel Bartels, but I'm not happy with the contact so I'm going to make a new full sized tool before doing an more polishing. I've attached a ronchi image and the open fringe report which seem to agree in general terms.
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