Re: ATM Apodizing Mask

["Frank Q" <frank@katestone.com.au>]

Hi David/All

Yep, I got the GIF File.

We used a similar type of arrangment to break the
diffraction edge on the rims of acoustic sounder shields.
Here extraneous sound can diffract around the edge of
the shield and find its way to the transducer - not good !!

For the optical case, it is the sharp (ie 100% reflection
/ transmission to 0% refl/trans) regular edge (I was almost
going to say "straight edge") of the objective that causes the
observed Airey pattern. If we break the edge into lots of
edges which are at "strange" angles (as was shown in David
Nicholls image) then this will disrupt the ring pattern although
I believe that the central maximum or Airey disk will be
fractionally larger as a result.

FWIW
Cheers
Frank Q