[Elecraft] Why predistortion ?

[Paul Van Dyke]

Well part of the problem with the original Hubble lenses where they were
miss ground in the 1st place

Paul KB9AVO

On Tue, Sep 15, 2020, 9:57 PM Fred Jensen <k6dgw at foothill.net> wrote:

> Isn't that what they did to Hubble originally?
>
> 73,
>
> Fred ["Skip"] K6DGW
> Sparks NV DM09dn
> Washoe County
>
> On 9/15/2020 5:41 PM, Drew AF2Z wrote:
> > That's funny, I was also thinking of astronomy-- the
> > Schmidt-Cassegrain telescope where the inherent aberrations of the
> > relatively simple spherical mirror is corrected (pre-distorted?) with
> > a lens...
> >
> > 73,
> > Drew
> > AF2Z
> >
> > On 09/15/20 18:39, Fred Jensen wrote:
> >> Didn't the term "pre-distortion" originate in the astronomy world
> >> where one creates an artificial star with a powerful laser, and then
> >> distorts the telescope mirror in real time to minimize atmospheric
> >> effects [twinkling]?  That also reduces the twinkle on real nearby
> >> stars too. Maybe that's something else.  Pre-emphasis/De-emphasis in
> >> FM broadcast [and analog land mobile FM] is sort of pre-distortion too.
> >>
> >> 73,
> >>
> >> Fred ["Skip"] K6DGW
> >> Sparks NV DM09dn
> >> Washoe County
>
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