Re: ATM An Old TMs Simple Query

["Richard F.L.R. Snashall" <rflrs@rcn.com>]

Jerry Hudson wrote:
> To ol' Coyote -
> 
> Your formula,
> 
>> a*rho^2+b*rho^+b*rho^4...
> 
> giving the shape of the Schmidt plate, is
> exactly opposite in sign to the wavefront
> aberration describing an uncorrected spherical
> mirror.  The glass introduces just enough extra
> path length where it is thicker to compensate.
> 

In fact, Kingslake uses this exactly.  Couched
in the latter part of the proof:

	"Along the axis this optical path is
	evidently (nt+r+a).  Equating these.."

I was slightly taken back when I saw this.  Don't
know why, just was.

		Rick S.