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Re: [ATM] first ronchi images,,,, ouch
I think you have some very strange and weird astigmatism. These errors are, IMHO, easier to see with ronchi than with foucault. IMHO, the cure is to turn your mirror and your lap much, much more frequently; check whatever it is that the underneath item is lying on; think about putting it on some outdoor carpet or something like that; and polish for a good long time. I think you also have TDE, which short strokes with a relatively hard lap for about 1/2 to 1 hour will eliminate.
But 1/3 COC with lots and lots of random rotation should solve the astigmatism.
If you don't fix the astigmatism, the scope will not gie you good views.
That is my 2 drachmas.
Guy
Jim Burrows <burrjaw@earthlink.net> wrote: At 2006-03-09 03:14 +0000, Charles wrote:
>So I decided to put it on the ronchi and
>take a few photos,,,, well here is the link, please try to be kind. I do
>want feed back though as I believe I have a turned down edge, and maybe
>more.... any advise you can give is allways gratefull.
>http://www.geocities.com/quantemlp/page4.html
In muh opinion, as our commander-in-chief sez, the funny little bulges on
the left side of the in-focus images are from the grating, not on the
mirror. But I don't have the years of Ronchi experience that Mel Bartels
has, indeed none . So I'd suggest hacking up a mask, get behind the
knife edge with pencil and note paper, and do some Foucault tests to see
what is REALLY going on with the mirror profile.
Guy Brandenburg
Washington, DC
My home page:
http://home.earthlink.net/~gfbranden/GFB_Home_Page.html
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