From: Mel Bartels 
cc: atm{at}shore.net
Reply-To: Mel Bartels 


> >The star test is supposedly good down to 1/50th wave, but I've never read
> >anything about what it looks like at this level.


Is this Peak to Valley or RMS, and in what wavelength of light?  I am not
trying to give anyone a hard time - but 1/50th with explanation is pretty
much meaningless.

My experience with the star test shows two divisions based on aperture:

if 10 inches or under, star test maybe in experienced hands (that's a big
if) can catch 1/25 RMS visible light, usually though is 1/2 to 1/3 that
detectable

if 16 inches or larger, the ability is halved because seeing makes top
notch star testing so difficult

Mel Bartels

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