Re: [ATM] 6-points cell voor 20 inch mirror?

["Arjan te Marvelde" <arjan.te.marvelde@hetnet.nl>]

Mark,

I don't think this statement scales very well. Some cell designs are less
susceptible to construction errors than others. I believe that especially
the 3 and 6 point cells can take a smaller error margin (i.e. factor 2
rather than 4). Also the pad size will influence this factor.

/Arjan te Marvelde

>>>I have been advising an upper cut off of 2.5 nm, so I would not usually
say this cell is good enough for this mirror.  I know 2.5nm sounds
awfully low.  There is a reason.  Jeff Anderson Lee made a study with
Plop, investigating the effect of construction errors on the resulting
deformations.  He found that errors of a magnitude that could reasonably
be expected in home workshop construction, 1 to 2mm, can worsen residual
deformation by a factor of 2 to 4.

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