Mark,

I see what you mean about the distortion, but still better images than I
have done so far! You mentioned that you do not use the 'spacer'. Is that
the T-thread extender that comes with the FR?. What is it's purpose if you
can do without?

Another question I had involves the proper FR to CCD chip distance. In my
setup, what is the optimum placement? The spacer may have something to do
with that, but if so, does the position (or lack) of the CFW8 screw that up
(as it is in between the two)?

Thanks for the site URL, it was nice to see real pictures explaining what
you were talking about.

Anthony J. Kroes
Green Bay, WI


> -----Original Message-----
> Mark de Regt
> Sent: Tuesday, August 28, 2001 12:09 PM
> Subject: [M]: RE: Focal reducer recommendation
>
>
> Anthony--
>
> I image with a 10" LX200/NGF-S/Meade f/3.3/CFW8/ST-7E. I use this without
> spacers, and get an effective focal ratio of f/4.6. I have no
> problems with
> back focus; there is some field distortion at the edges;
> vignetting is mild.
> I very much doubt either would affect astrometry or photometry, but I only
> take pretty pictures, so I cannot say for certain.
>
> I like the f3.3 reducer, since it significantly increases my FOV at an
> acceptable cost in distortion. Also, between the unsettled air where I
> live, and the less than rock-solid LX200 mount, the lower
> resolution is more
> forgiving.
>
> The Meade f/3.3 reducer cannot be used visually, only for imaging.
>
> To get an idea what distortion there is (and isn't), you can look at my
> images.
>
> http://home.earthlink.net/~akilla/MAD
>
> --Mark de Regt
>
> > -----Original Message-----
> > Anthony J. Kroes
> > Sent: Tuesday, August 28, 2001 8:56 AM
> > Subject: [M]: Focal reducer recommendation
> >
> >
> > I am upgrading my scope from 8" to 12"LX200 and was wondering what the
> > current opinion is for recommended focal reducers. I have the
> Meade .63,
> > but am looking at getting a bit wider field of view through the
> > Meade 3.3 or
> > Optec 5.0 or 3.3 reducers via my ST7E.
> >
> > I have read the review/comparison by Chris V. in the archives, but was
> > wondering if there is a different current opinion, and whether
> anyone had
> > direct experience with the using either with the following
> optical train.
> >
> > 12" LX200 / NGF-S / (some brand of .33 FR) / CFW8 / ST7E
> >
> > I am used to working with an 8" LX200, f6.3 and my concerns are
> > vignetting,
> > the 'yellow filter' problem with Optec FR's, sufficient backfocus
> > with these
> > to still be able to use the CFW8, and if either will affect
> astrometry or
> > photometry - fields I wish to explore further with this setup.
> >
> > Any help or constructive opinion either way will be appreciated
> >
> > Anthony J. Kroes
> > Green Bay, WI
> >
> >
> >
>
>

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