Re: [APML]: Meade/Celestron Focal Reducers

["Philip Perkins" <philip@astrocruise.com>]

> No, I was thinking of using one in a mirror testing scheme I've dreamed
> up. The test uses laser beams, and measures spherical aberration along
> the optical axis. I wanted to put one of these in-line, so I was
> wondering how much aberration they have.

Not seen any sign of spherical aberration but they definitely reduce coma -
also unfortunately they introduce very severe vignetting. I've used both
Meade and Celestron devices (still have the Celestron one) - you can see an
actual image of the vignetting (if interested) under Articles / Lumicon GEG
Report on my page ... 
http://www.astrocruise.com

You should find it under the Vignetting section of that report ...

Philip Perkins  --  philip@astrocruise.com
51 27'N 1 36'W  --  Wiltshire, UK
43 54'N 5 32'E  --  Luberon, France
Astrocruise     --  http://www.astrocruise.com