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Cheap aspheric lenses?



 
 
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  #1  
Old March 5th 04, 07:22 PM
Richard
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Default Cheap aspheric lenses?

The University of Rochester has developed a machine that can produce
positive aspheric lenses to 1/20th wave in minutes. The machine,
called
something like Magnetohydrodynamic, uses a moving belt with a special
liquid layer. The liquid has a marked surface tension. The lens
blank
is held on a spindle and pressed to the liquid on the belt. The
liquid
depth is about 2mm and the submersion of the lens in the liquid (depth
controlled submersion) produces specific pressures and material
removal.
This method avoids many problems associated with other forms of lens
"grinding." The process has been commercialized and could have a
marked
effect on the cost of implementing aspherics in eyepiece designs.
Now I'm waiting for the distortionless, Plossl-sized eyepieces with
100 deg. fields for $200!!
  #2  
Old March 5th 04, 07:41 PM
Thomas M
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Default Cheap aspheric lenses?



This method avoids many problems associated with other forms of lens
"grinding." The process has been commercialized and could have a
marked
effect on the cost of implementing aspherics in eyepiece designs.
Now I'm waiting for the distortionless, Plossl-sized eyepieces with
100 deg. fields for $200!!


What about cheap objectives with above average quality?


  #3  
Old March 5th 04, 09:57 PM
Chris1011
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Default Cheap aspheric lenses?

The University of Rochester has developed a machine that can produce
positive aspheric lenses to 1/20th wave in minutes. The machine,
called


This is not new, it has been covered here on SAA before. The technology is now
some 8 years old. There is a company in Rochester that has been selling
machines for this purpose for several years. It is not cost effective for
amateur or commercial optics. Forget about having anything like this for
objective lenses too.

For eyepieces, molded aspheric optics might someday be cost effective. These
are being used right now in consumer digital cameras. I don't know what this
will buy you over eyepieces that are now available.

Roland Christen
  #4  
Old March 6th 04, 08:02 PM
Richard
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Default Cheap aspheric lenses?

"Thomas M" wrote in message news:oJ42c.74189$A12.52233@edtnps84...
This method avoids many problems associated with other forms of lens
"grinding." The process has been commercialized and could have a
marked
effect on the cost of implementing aspherics in eyepiece designs.
Now I'm waiting for the distortionless, Plossl-sized eyepieces with
100 deg. fields for $200!!


What about cheap objectives with above average quality?


I don't know how large a lens it can be applied to.
-Rich
 




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