Re: [APML] Photographic test of Meade 8" f/4 Schmidt-Newton

["Chris Schur" <cschur@cybertrails.com>]

Walter, sounds like there is quite a variation in the optics here.  mine is
sharp on 35mm up to about the 80 percent zone, then the coma is the dominant
factor.  With small CCD, I got this image:

http://www.psiaz.com/schur/astro/IMAGES/ccd/m17-5mblend-1.jpg

Chris Schur
----- Original Message -----
From: MNewton <mnewton1@bellsouth.net>
To: Discussion of Film Astrophotography <astro-photo@seds.org>
Sent: Monday, May 26, 2003 10:32 PM
Subject: Re: [APML] Photographic test of Meade 8" f/4 Schmidt-Newton


> Chris, this Meade 622, was it the f3.6 schmidt-newt? I have just bought
one,
> it has a boat-load of astigmatism
>
> ----- Original Message -----
> From: "Chris Schur" <cschur@cybertrails.com>
> To: "Discussion of Film Astrophotography" <astro-photo@seds.org>
> Sent: Monday, May 26, 2003 11:25 PM
> Subject: Re: [APML] Photographic test of Meade 8" f/4 Schmidt-Newton
>
>
> > Walter, You are obtaning similiar results that I got with my Meade 622,
> the
> > predecessor of the latest series of schmidt newtonians.  I believe that
> > while it is usable as a film camera, it really shines as a CCD
instrument,
> > the center of the field being bright and exposures are quite short.
> >
> > Thanks for sharing.
> >
> > Chris
> > Astrophotograpy site: http://www.PSIAZ.com/schur/astro/index.html
> >
> > ----- Original Message -----
> > From: Walter Koprolin <a9125657@unet.univie.ac.at>
> > To: <astro-photo@seds.org>
> > Sent: Friday, May 23, 2003 5:15 AM
> > Subject: [APML] Photographic test of Meade 8" f/4 Schmidt-Newton
> >
> >
> > > Hi everybody!
> > >
> > > This might be of interest to the group:
> > >
> > > I recently had the opportunity to shoot two 35mm astrophotos with a
> Meade
> > > 8" f/4 Schmidt-Newton. I have written a short test report about it:
> > >
> > > http://www.astro.univie.ac.at/~koprolin/Art/SN8/
> > >
> > > As you can see, the telescope is problematic in astrophotographic use.
> The
> > > images suffer from vignetting and distorted stars near the edges. If
> > > bright stars are present near or within the photographed field,
multiple
> > > reflections and Schmidt ghosts also become a major hassle.
> > >
> > > All these artifacts except the radial distortion of stars can be
> > > eliminated or nearly eliminated during image processing, but some of
> them
> > > only with considerable effort.
> > >
> > >   Walter Koprolin
> > >   Gallery of Astrophotography & CCD, Observation Reports,
> > >   Telescope Testing: http://www.astro.univie.ac.at/~koprolin
> > >
> > >
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> >
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>
>
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