Re: Re[2]: [ATM] A new flat-field anastigmatic aplant?

["vladimir" <svla@isp.com>]

Hi Richard,

> The design optimises nicely :
> 
> Surf      Radius    Thickness       Conic
> OBJ    Infinity     Infinity           0
> STO    -2423.31    -1319.082  -0.9518228
>   2   -351.6338     279.1091           0
>   3   -410.7441    -505.7408           0
> IMA    30559.74                        0
> 
> Tertiary has 62mm central hole. Design was optimised
> with EFFL=-1100mm
> 
> Focal plane curvature of about 100 feet, and worst case spot
> size over a 1 degree FOV is 0.3um rms, 0.6um geometric for a
> 4.9um airy disk. Worst case Strehl 0.997. Big central
> obstruction though. 

Much obliged - it was really bugging me. Turns out that
there is little difference between Zemax and Atmos. 
With this same input, RV Raytrace gives roughly twice larger 
compact off-axis geometric blur, with a few rays scattered over 
4-5 mu area, and Winspot gives a 2-3 mu compact blur.
I'd say they're still doing pretty well for the money. 

CO is unacceptably large for 1 degree field, assuming full
illumination or acceptable edge vignetting. This particular system
can't handle more than 0.5-0.6 degree field diameter with
acceptable edge vignetting and CO. When scaled down for an
f/3 primary and f/2.7 effective system, it comes close to 
handling 1 degree field diameter w/acceptable CO (~60%).
The spot is still less than 2 microns across the field.

It may be possible to design a system with better field/CO.
Don't know at this point.

Keep that Zemax running... :)

Vlad



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