Re: [ATM] RC cass secondary and starlaps.

[Kevin MIchael Zabbo <chaosopher23@yahoo.com>]

I have not made my secondary yet, but that time will
come.

I still have to make my primary into a parabola (the
silicone replacement for pitch did not work, it didn't
do anything worth mentioning, previous claims of being
faster were because of a faulty test setup) and decide
on a single cage or interchangeable cages for
Newtonian, Cassegrainian, and Gregorian secondaries. 
That question is left up to how much machine shop work
I'm willing to buy.

Primary needs a more rigid test setup where I can do
fast repeats between test and figuring.  I need some
hard pitch to do it right, too.  The stuff I have is
too soft, even though it's 50 degrees average this
time of year in MS.

Kevin
--- Ken Hunter <atm_ken_hunter@yahoo.com> wrote:

> Congratulations Jim!
>    
>   When you feel that you have nailed the procedure
> down, please write it up so that we can share in
> that knowledge. Bill Mariott and I are going to
> follow the same path as you except we are going to
> be making 20 inch RC cass's with Fused Quartz
> elements. You wouldn't want to try a big one later,
> or would you? I still have a 20 inch FQ blank and
> smaller pieces available.
>    
>   Ken Hunter
>   
> 
> Jim Burrows <burrjaw@earthlink.net> wrote:
>   I have finally, FINALLY, gotten the wavefront RMS
> down to 32.1 nm on 
> my 10" RC cass (one test only, more to come, and if
> they agree, on to 
> a star test).
> 
> I've been using starlaps for figuring the secondary,
> many, many laps 
> with 4 petals and only very small RMS improvements.
> 3 or 4 spells 
> ago, I tried 3 petals - WOW, big difference! The RMS
> went from 106 
> down to the 32. I'm guessing there might be a little
> physics going 
> on here - if one petal of a 4-petal lap wears down,
> the mirror-lap 
> contact may be determined by the other 3 petals,
> like a stable 
> 3-legged stool, but then the overall shape of the
> lap would be incorrect.
> 
> -- Jim Burrows
> -- http://home.earthlink.net/~burrjaw
> -- mailto:burrjaw@earthlink.net
> -- Seattle N47.4723 W122.3662 (WGS84)
> 
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Wanted: Literary agent to represent me as an author.  I have two horror-science fiction novels ready to publish and several more in process.  See first chapters and more at: http://www.myspace.com/kevin_magi_93

Thank you.


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