Re: [ATM] Non Achromatic Eyepieces

[George Anderson <tillerman1@videotron.ca>]

If memory serves me right...
Try doing a web search on Petzval, the second set of lenses is located
near the focal mid point, and I believe that the colour correction is
quite good on this configuration.
Roland (of AP fame) posted a perscription for a petval scope on SAA some
years ago (around 1998 I believe) and with his permission I re-posted it
here around the same time.

George Anderson
Montreal Canada

Clear skies and good health

Anthony Stillman wrote:
> 
> >...special eyepieces to correct secondary color
> 
> The farther the correcting element is from the abberating element, the more
> difficult it is to correct the abberation.
> 
> Correcting secondary color half or so way down the light cone is quite
> do-able.  Roger Ceragioli has done some work in this area and reported it.
> Here are links to a few of his postings.  I'm sure I remember a post where
> he described a working telescope that he'd made, but I couldn't find it.
> 
> <http://astro.umsystem.edu/atm/ARCHIVES/FEB00/msg00691.html>
> 
> <http://astro.umsystem.edu/atm/ARCHIVES/FEB00/msg01348.html>
> 
> <http://astro.umsystem.edu/atm/ARCHIVES/FEB00/msg01352.html>
> 
> <http://astro.umsystem.edu/atm/ARCHIVES/FEB00/msg01404.html>
> 
> <http://astro.umsystem.edu/atm/ARCHIVES/MAR02/msg00539.html>
> 
> Anthony
> 
> reddite quae sunt Caesaris Caesari
> Give back what things that are Caesar's to Caesar.
> 
> (Render unto Caesar what is Caesar's.)
> 
> In Latin all "c" -s are hard.  Brings new meaning to what the Prussians
> thought of themselves.
> 
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