My first laser cut Nipkow disc http://www.taswegian.com/NBTV/forum/viewtopic.php?f=35&t=2452 worked really well but the apertures have a thickness of 1.5mm so there is considerable parallax when using a magnify glass as the focal point is close to the disc. When no magnify glass is present there is very small parallax occlusion. I even get overlap at this point.
Here is a comparison of the same disc. Left side no magnifying glass, right side magnifying glass
This brings me to the idea that I can laminate some 0.38mm polypropylene to some clear acrylic to get a rigid/thin aperture accurate disc I will give this a go when I get some time.
I cut the smallest hole I could in 0.38mm polypropylene, it turned out right on 0.2mm if you discount the intended round hole overlap. Here is a pciture. I will have 0.38mm black polypropylene in stock next week. I tested the 0.6mm black and it has no detectable light leakage
Mircons haha... Microns woops
Cheers
Keith