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Re: ATM First Mirror, First Test, First TDE?


Edwin,

When you work TOT, in general you are pushing down the edge.
When you work MOT, in general you are pushing down the center.
This is stroke dependent.  That is if you work with a center over center 
stroke (1/3 diameter) you don't effect the figure much at all.  If you 
add a little (narrow) W (still 1/3) you start to effect the figure.  If you
make your strokes longer, some unusual things can happen.  For example a 
long C/C TOT stroke will create a flat bottom (ok not really flat, but less
curved) and a steep edge. \_______/  This is counter intuitive, but its what 
happens to me (I tend to uses strokes which are too long)  If you work C/C MOT 
with really long strokes, you deepen the center and flatten the edges. 
<html><pre>
_         _
 \       /
  `-_ _-'
</pre></html>
again this is an exageration.  This is how you parabolize small mirrors.
    
I try to pay attention to my stroke length and keep it short.  For your specific
situation I would work 1/3 MOT C/C with a narrow W for 15 or 30 minutes and see 
where it was taking me.  If there wasn't making much difference I would widen 
the W.  Many people with a TDE just polish out to a sphere again (1/3 W and 
1/3 C/C and then go on.  I try to cut corners.  It rarely helps

Anthony