[geeks] New Horizons

[Sridhar Ayengar]

Sandwich Maker wrote:
> " From: Patrick Giagnocavo 717-201-3366 <patrick at zill.net>
> " 
> " 
> " []
> " 
> " 
> " Later, lenses whose surface is not part of a section of a sphere, known as aspherical lenses, also became possible (the Leica Noctilux f1.2 lens, which was also based on a highly modified Planar design that Leitz has been working with for over 60 years now).  
> " 
> " It was certainly known that asph. lenses could correct certain lens defects, but the difficulty was in producing them.
> 
> am i right in guessing that the surfaces on real aspheric lenses are
> -conic-sections- [in rotation]?  i'm think what parabolic, hyperbolic,
> etc mirrors do for telescopes.

Even a sphere is a rotated conic section.

Peace...  Sridhar