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 <[email protected]> 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 > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[email protected] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to [email protected] ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [email protected]
