Re: [ATM] 20" F4.5 Done

[Mitch_Bisnauth@Cknainc.com]

MitchR.....I don't know anything about testing mirrors - but that would 
make Pegasus's residual "system" error is bigger than the actual measured 
item, (in rough numbers 1/20 = measured item & 1/10 = "system 
error")...seems reverse of what you would expect, (or have I got this 
entire statistics/metrology thing wrong w.r.t mirrors....??)

Geogre --- What is Pegasus's explaination?

(--- is it a "localized" w/front reading that was generated with the 
mirror in a specific orientation? )

(That scope looks like a work of art...)

MitchB



"Mitchell R" <funnybone101@embarqmail.com> 
Sent by: atm-bounces@atmlist.net
01/30/2008 06:43 PM

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<atm@atmlist.net>
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Subject
Re: [ATM] 20" F4.5 Done







Hi all
Finally I finished the construction of my telescope. 
A 20" with F4.5 Primary Mirror from the Pegasus Optics 
and a 4" secondary from the Antares Optics. 
It took me 4 months with very afternoon and evening job,

too running for materials and highly improvisational ... 
Details of the construction finished and standing, you can see 

http://geonik.homeip.net/home/complete/tabid/106/Default.aspx

I received measurement data from John Hall director of Pegasus optics,

Listed below.
There seems a Wavefront PV Error 1/19.71 Wave 
but below there is a Worst Case P-V Error 1/9.93 Wave 
What I finally can not understand is what is my mirror Wavefront error? 

I bet that there is 1/9.93 Wave, but the 1/19.71 is confusing me.
Can someone explain that to me?


***
Let me first say what a nice looking scope! Very nicely done! 
My *guess* would be the company has a certain amount of determined max 
error
in their testing that they find from mirror to mirror or set or readings 
to
set of readings and factoring in the "error factor" if you will they are
stating that even if their testing was off by their determined max error 
it
would still be 1/9.9 wave. 

Hope my wording is understandable, and again that's my idea, not really
sure.

Anywho, Great scope!

Mitchell 


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