From: "Jeff Anderson-Lee" 
To: "Michael Peck" , "James Lerch"
        
Cc: "ATM List" 
Reply-To: "Jeff Anderson-Lee" 


> First - and unfortunately - second impression: The agreement between Robo
> and these interferometric results is not so good. Here are estimates of
> surface RMS from Robo and Royce:
>
> 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
quote page 2 of the report: "Surface errors are 1/2 these
numbers", so isn't the the surface error given buy the report 1/2 of
38nm or 19nm?

If Robo reported a surface error RMS of 20.0 nm, then the agreement is
within 1.0nm or 5%.  Not bad.

Jeff Anderson-Lee
Scramento, CA

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