Re: [ATM] TUE Turned up edge

[Mike Lockwood <melockwo@uiuc.edu>]

Rodney,

Rodney Mayes wrote:
> Hi,  I haven't posted in quite some time, but I could sure use some
> help at this point.  I definately have a turned up edge on my 10"
> f/7.5.  It is completly polished.  I believe I have a high center
> as well.  My question is this: can one begin parobolizing on a
> mirror with TUE?  Will deepening the center by parobolizing
> eliminate the TUE?  Or, is this just wishful thinking?  Would you
> try reducing the edge first then working the center?  Work the
> center first?  Forgive my ignorance.  First time mirror maker here.
> Any help appreciated.  Thanks in advance.  Rodney 

 From the sound of it (TUE, high center), you have an oblate sphere. 
Actually I suspect you have a turned-up outer zone, and a turned-DOWN 
edge (TDE).  If the diffraction ring around the outside of the mirror 
is brighter on one side than the other, then that indicates TDE.

Here are a couple of pages that might help you out:

http://bi-staff.beckman.uiuc.edu/~melockwo/mirror_making/oblate/oblate.html
http://bi-staff.beckman.uiuc.edu/~melockwo/mirror_making/full_lap/full_lap.html

Don't forget to search the list archives for terms like "oblate 
sphere" or "turned up edge".  Searching before asking a question is 
appreciated, but you have to find the right phrase to use in the 
search, so it can be challenging sometimes.

	Mike Lockwood

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