Re: ATM 11.2" F/2 Primary testing questions :)

["Bill & Lois Kelley" <wekelleylwk@sedona.net>]

To All,
I decided to forward this to the gurus on the list after I
sent the comments and query below to Tommy. He answered part of them
by saying the 65" F2 mirror was of cellular construction and would be
spherical
and flexed. Does anyone have any idea how this could be flexed to a
parabola?
The analysis I ran assumed solid mirrors of 3 to 5" thick with an equal
radius on
the back. And an Adler annulus puller gave terrible results at all
thickness.
I know you can't flex cellular mirrors because I have a 6" F5 cellular
mirror,
and the open cells printed through badly to the surface figure when flexed.

I hope this guy is onto something we don't know- any ideas??
Regards,  Bill Kelley


----- Original Message -----
From: "Bill & Lois Kelley" <wekelleylwk@sedona.net>
To: "AstroIdiot" <tgooch@arkwest.com>
Sent: Monday, December 31, 2001 10:22 PM
Subject: Re: ATM 11.2" F/2 Primary testing questions :)


> Tommy-
> Pardon me for butting in, but this was also posted to the ATM list and
> I couldn't resist. Since I worked with Alan Adler to develop flex, I
> decided to run a flex analysis on a 65" F2 mirror. I presumed it was
> not of cellular construction since when flexed the cellular shape prints
> through to the surface (and very badly so). I tried different thicknesses
> from 3" to 5", but couldn't get a figure better than 1/10th wave. At 5"
> thick the tension required was up in the many thousands of pounds and
> beyond the programs ability to calculate, allowable wedge was something
> less than 1/10,000th of an inch, and the gravity effect was above 200%.
>
> There must be something I am missing! ??
>
> Congratulations on your excellent new friends, and my best to you in
> the New Year.   Regards-  Bill Kelley
>
>
> ----- Original Message -----
> From: "AstroIdiot" <tgooch@arkwest.com>
> To: "Ric Rokosz" <radicell2@yahoo.com>; "James Lerch"
> <jlerch1@tampabay.rr.com>; <atm@shore.net>
> Sent: Monday, December 31, 2001 2:10 PM
> Subject: Re: ATM 11.2" F/2 Primary testing questions :)
>
>
> >
> > Talk about fast mirrors I'm excited. An old friend of Rick and Richard
> > moved his operation up the road from me. You may remember
> > Ray Demaris of Stabilite. I watched part of the construction of a 65"
> > F2 in front of his shop and he is also working on a 72" for a major
> > university. 72" (6 foot) glass disk is beautiful to behold. He is very
> > friendly and I'm going to try to pick up some tips and help on mirror
> > making. He slumps his faceplates and fuses the ribs in his oven (big
> > enough for even larger blanks) and has an interferometer setup large
> > enough to test these monsters.
> >
> > Tommy
> > P.S. The 65" is for personal use and is a sperical mirror that is flexed
> > into shape at the eyepiece. (I've hit the ATM motherload)
> >
> >
> > ----- Original Message -----
> > From: "Ric Rokosz" <radicell2@yahoo.com>
> > To: "James Lerch" <jlerch1@tampabay.rr.com>; <atm@shore.net>
> > Sent: Monday, December 31, 2001 9:15 AM
> > Subject: Re: ATM 11.2" F/2 Primary testing questions :)
> >
> >
> > >
> > > ---
> > > Ric
> > > Toronto,CDN
> > >
> > > __________________________________________________
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> >
> >
> >
> >
>