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Re: [ATM] Re: Satisfying "Millies-Lacroix" is neithernecessary nor sufficient for "diffraction-limited" performance?"

At 2004-06-23 20:07 -0400, Vladimir Sacek wrote:

>This sounds more like Conrady than lord Rayleigh. As I gather, the
>original Rayleigh's criterion was derived from  a number of empirical
>test for spherical aberration *at the paraxial focus", coma and
>astigmatism (Applied Optics II, p626). The 1/4 wave wavefront error
>criterion was generalized, and it was assumed that it causes
>approximately 20% fainter central disc.

V. N. Mahajan (inventor of the best Strehl approximation from RMS, "Strehl 
Ratio for primary aberrations...", J. Opt. Soc. Am. 9(72), Sept. 1982, p. 
1262) says, "Rayleigh (Philos. Mag. 8, 403 (1879)) showed that a 
quarter-wave of primary spherical aberration reduces the irradiance at the 
Gaussian focus by 20%...".  So I guess Rayleigh had computed it, and got it 
right to 4 decimal places - Mahajan says the Strehl ratio for 1/4 wave 
spherical aberration is 0.8003.

         -- Jim Burrows
         -- mailto://burrjaw@earthlink.net
         -- http://home.earthlink.net/~burrjaw
         -- Seattle N47.4723 W122.3662 (WGS84) 

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