my name is Hans-Heinrich, I live in Austria/Europe.
Please let me draw your attention to a software that I have recently written: VCS-Virtual Couder Screen - Version 2
When parabolizing my 350mm 1:5.8 mirror some years ago I decided to use a webcam in order to display the Foucault shadowgrams on a computer's display. This was very comfortable but I was not satisfied with the commonly used couder screens positioned in front of the mirror. All those problems with difraction in small zones, difficult brightness-comparison of related zones, the great number of visible zonal apertures and so on.
This is why I wrote a software that emulated couder screens directly on the computers display. There was no need to have a real mask any more! The software really worked very well, as there was of course no diffraction at all and thus I could realise very small zones.
Recently I have improved the software. The most important new functionality in this Version is 'Auto Compare', providing a fully automatical real time comparison of zones - much more exactely than a visual comparison!
Other benefits are:
- Automatical comparison of zone brightness exactely along the effective radius. A great advantage e.g. when measuring the outer zone. An eventually existing sunken edge is visible but it does not influence the measuring results at all.
- 'Anti Seeing' mechanism
- Count of zones can be varied arbitrarily
- Flexible zone radii according to Texereau, Couder, N.O. Carlin, Pin Stick plus free radius definition
- Comfortable management of readings (automatic averaging)
If you are interested please watch this introduction video:
Here a video showing how 'Anti Seeing' works:
And here is the link to my website:
Alois Ortner, a very well known austrian optician has tested VCS and writes in a german forum (http://www.astrotreff.de/topic.asp?TOPIC_ID=130724
"VCS is fast and accurate. ... I was astonished when making repeated readings, could hit the center (I measure without a central obstruction) with +- 0.01mm, the zones with +-0.006 mm and the edge with 0.003 mm"
Greetings from Austria