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[ATM] Flexing the Ubiquitous 4.5-inch Mirror

Hi,
 
I am trying to decide if flexing a 4.5" mirror using Alan Adler's method over Bill Kelley's original center-pull method will give me detectbly better views at the eyepiece. Alan's method looks easy enough.  My only real concern is it adds a bit of additional height to the mirror cell.  I really don't have the option of moving the spider and focuser forward.  My understanding is that if I did use Alan's method and went with aluminum instead of polycarbonate, I can reduce the thickness of the plates by something like one-third.  Is that right?  Anyway, here are the FLEX.EXE inputs and SPOT RATIOs. Please let me know what you think.
 
Thanks
 
David Taft
Manassas, VA
 
"This is particularly true for the ubiquitous imported 4 1/2-inch telescope mirrors...."

 

     Alan Adler, S&T November 2000 

     "Flexing Spheres into High-Quality Telescope Mirrors"


~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~



Unflexed Sphere:

 

DIAMETER -------------------------------------------------> 4.5

NUMBER ---------------------------------------------------> 8

MIRROR-BLANK THICKNESS -----------------------------------> .64

SECONDARY DIAMETER or 0=CALCULATE A GOOD SIZE ------------> 1.1

PULLER BETA1 or 0=FIND BEST or 1=APPROXIMATE WITH RULE ---> 0

PULLER BETA2 or 0=FIND BEST or 1=APPROXIMATE WITH RULE ---> 0

BACK SHAPE SPEC (SEE NOTE BELOW) -------------------------> 1

TAPER EXPONENT or 0=SPHERICAL BACK -----------------------> 1

FLEX: 1=FIND FLEX   0=ANALYZE UNFLEXED SPHERE ------------> 0

 

SPOT RATIO= .569  

 

Adler:

 

FLEX: 1=FIND FLEX   0=ANALYZE UNFLEXED SPHERE ------------> 1

 

SPOT RATIO= .008  

 

Kelley:

 

PULLER BETA1 or 0=FIND BEST or 1=APPROXIMATE WITH RULE ---> .01

PULLER BETA2 or 0=FIND BEST or 1=APPROXIMATE WITH RULE ---> .1

 

SPOT RATIO= .173  

 


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