Homebrew PCBs

On Sat, 8 Jan 2005 12:24:58 -0800 (PST), ron amundson  
<mnphysicist@...> wrote:

>
> Another possibility is to put a slightly higher
> pressure within the optical train. Just make sure its
> clean air. You can put vent holes near the exposed
> surface of the lens as well. However, getting the
> hole's correct can be tricky...  We built a optical
> system for a saw mill blade years ago, and it stayed
> pretty cleaned compared to everything else in the
> vicinity.
> For what you are doing, the thin lens equations should
> work fine, as you don't need to be too concerned with
> off axis distortions, or even chromatic distortion of
> the image.
> Ron

I guess a small fan with a good filter could be used for that, my shop air  
isn't oil free.
blowing dust away from the lens sounds good.
But then, i have a better idea, why not use a vacuum cleaner to collect  
all the dust away from the
lens. Better dispose of it than have it in the air. The new vacs are a lot  
less noisy than what i'm used to, must look out for one in the junk i can  
repair.

ST