From: Guy Brandenburg 
To: David Lonard ,  atm{at}shore.net
Reply-To: Guy Brandenburg 


I must say, that is the strangest looking lap that i have ever seen. How
did you make it? The lap is the most important thing about the process. Guy
Brandenburg

David Lonard wrote:
>
>
> Hello Group,
>
> I would like to thank all those who have given advice.
> So far the biggest consensus that I have received thus
> far has been to extend my stroke to bring the sphere out
> further to the edge, which I have been doing and seems
> to be working well.  I have still been concentrating a
> lot of strokes along the more spherical axis since I
> still think that the edge is higher along this axis.
> Along the more hyperbolic axis, I am using a longer W
> (or V?) stroke.  I have an updated ronchigram photo at
>
> http://www.geocities.com/lonard3/mirror.jpg
>
> I have also made what I hope is a more reasonable star lap
> as was suggested.  Several of you have said that I should
> wait on the star lap, but I have tried using the full
> lap and things go wildly oblate spheroid when I do so.
> At any rate, the ronchi bands are getting rather straight
> with this current lap so I think it is currently useful.
>
> To answer your question about machine work Dennis, when
> the surface came to polish, the ronchi pattern was packed
> with multiple nasty zones, too many and too deep to honestly
> know if I had astigmatism at that point.  The 12/24/02 image
> is the product of probably 20 hours of subsequent hand
> polishing.  I actually did put it back on the machine,
> but strong zones started to return, so I stopped.  To
> be fair, my machine isn't very mechanical sound, made
> out of wood and was practically destroyed during the
> violent hogging out process.
>
> I'm sure that there is still plenty of interest in a
> 20 x .875 inch mirror so I will try to give more
> updates.
>
> David
>
>
>
>
>
>
> _________________________________________________________________
> The new MSN 8: smart spam protection and 3 months FREE*.
>
http://join.msn.com/?page=features/junkmail&xAPID=42&PS=47575&PI=7324&DI=7474
&SU=
>
http://www.hotmail.msn.com/cgi-bin/getmsg&HL=1216hotmailtaglines_smartspampro
tection_3mf
>
>
>
>

--- BBBS/NT v4.00 MP