[ATM] testing tunnel

[Guy Brandenburg <gfbrandenburg@yahoo.com>]

Has anybody ever put pencil to paper (or mouse to screen) and described their ideal testing tunnel?

I'm somewhat frustrated by the environment I currently have to do ronchi and foucault and what-have-you testing. There is too much floor vibration, and also too many air currents, and you have to open a large gate, and so on. One of our regulars brought in a very large 120VAC muffin fan to experiment with, in order to see whether a blast of air from the side on the mirror would improve things; it definitely made it WORSE, even when held in someone's hands so that vibration of the stand wouldn't be an issue. We tried numerous different angles.

I'm thinking of using surplus 2 by 8s to make a long, heavy table about 24 feet long and roughly 28 inches wide, set along one wall of our workshop, with space underneath for storage of stuff. Why 24 feet? Because we have defnitely had some projects that required a ROC of 20 feet, and it's proably best to arrange for even longer than that. On top would be some PVC or copper or galvanized plumbing pipe arranged in such a way as to hold a shroud. The shroud would probably start off being black roll plastic, but might eventually graduage to some sort of cloth, using loops designed to hold shower curtains in place. This would of course require moving massive amounts of stuff around in the basement of the center where we hold classes. And I'm worried that some of the cabinets and so on that I would have to put in front of the 24-foot table would inevitably block access to some places we would want to put mirrors in.

Any suggesionts would be more than welcome.

Guy Brandenburg


"Thus, from the war of nature, from famine and death, the most exalted object which we are capable of conceiving, namely, the production of the higher animals, directly follows. There is grandeur in this view of life, with its several powers, having been originally breathed into a few forms or into one; and that, whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being, evolved."
- wrote Charles Darwin.
Guy Brandenburg, Washington, DC
My home page on astronomy, mathematics, education:
http://home.earthlink.net/~gfbranden/GFB_Home_Page.html
or else 
http://tinyurl.com/r6fh2
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