[ATM] Parabolization

[Francis J. O'Reilly]

I concur.

Polishing should be continued until sunlight magnified by a bi-convex lens 
of short focal length (A magnifying glass) passes through the surface of the 
glass in it's entirety.

Grey glass is unacceptable.

It does not coat well and is virtually useless as a reflective surface.

A rule of thumb once was two hours polishing for every inch of aperture, 
however with the polishing compounds now available, that rule may have 
relaxed somewhat.

Francis J. O'Reilly