Re: [ATM] Not tde or tue, important oblate spheroid, ellipsoid

["Jerry" <wa4guu@verizon.net>]

Number 1 is the correct stroke. Even though you have a hill in the center,
that stroke almost always will dig the center faster than outer zones. So it
is quite likely you will remove the hill faster than you correct the edge
zones.
 
Resist the temptation to work long sessions. 15 or 20 minutes of work and
then test. It is possible the hill will be gone in that time. If it isn't
going away then the stroke can be adjusted to do so. If you work too long
you could see a deep hole in the center the next time you test. That can be
fixed too, but you don't want to be bouncing back and forth from one problem
to another problem. 

I was just getting ready to send you this link to Mikes figuring page.

http://bi-staff.beckman.uiuc.edu/~melockwo/mirror_making/full_lap/full_lap.h
tml

Scroll down just a little beyond half way to section 1.2 Alternative
Parabolizing Strokes. The one on the left is what you want to do this time.
If you did not have the bump in the center then it would have been the one
on the right. Make the W as large as shown in the illustration but be
careful not to tip over the edge. Stroke slow.

Let me know how many lines per inch or lines per mm are on the Ronchi
grating you are using.

I would like to see another picture of the lap.

Jerry




-----Original Message-----
From: atm-bounces@atmlist.net [mailto:atm-bounces@atmlist.net] On Behalf Of
Mike Lockwood
Sent: Tuesday, January 08, 2008 11:38 AM
To: 'atm_list'
Subject: Re: [ATM] Not tde or tue, important oblate spheroid, ellipsoid

Hi,

Jerry said use the big W parabolizing stroke, which is #1 below. 
That's what you should use.

The center deepening stroke will dig a hole in the center in a hurry, 
and you don't need to do that now.

	Mike Lockwood

lütfü çakmak wrote:
> Thanks for your beneficial advice and everything. 
> I took courage from those.
> Mot big W ?
>
http://stellafane.org/atm/atm_mirror_ref/atm_strokes.htm#The%20Normal%20Stro
ke
> 1- the W normal stroke for parabolizing
> 2- the W center deepening stroke 
> Which one should do ? I took a little bit hesitation.


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