From: "Jeff Anderson-Lee" 
To: "Michael Peck" , 
Reply-To: "Jeff Anderson-Lee" 


"Michael Peck"  replied:
> At 04:28 PM 7/22/2003 -0700, Jeff Anderson-Lee wrote:
> > > My estimate from reprocessed images: 23.8 nm.
> > >
> > > James' original data (pooled): 20.0 nm.
> > >
> > > Royce interferometry:   47nm
> > >    minus coma                    46 nm
> > >    minus coma & astig.   38 nm.
> >
> >Yes, but Royce's measurement are reported in wavefronts, not waves.  To
>
> I converted all those numbers to surface errors in nanometers. Royce's
> "bottom line" number was something like 0.145 waves RMS on
the wavefront.
> Multiply that by his source wavelength of 633nm and divide by 2 and I hope
> you get 46 nm.
>
> I also subtracted off the astigmatism components in his report to get the
> number that I think would be most comparable to what you'd get in a
> foucault test. All of the numbers I listed should be "apples to
apples"
> comparisons if I did my arithmetic right. I'm rarely 100% confident my
> arithmetic is right, so I hope someone double checks my work.

Aw shucks.  I double checked your math and it works out to 46nm.  [Bummer.
I was hoping we just had a simple arithmetic error!]

One other question: would adjusting the reputed ROC affect the SE numbers
significantly?  I know that RTAFT tries to make a "best-fit"
computation of the ROC, which could produce a somewhat different result
than what Royce used (although I would be surprised if it was 50%
different!).

Jeff

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