Re: [APML] Newton-cassegrains: opinions sought

["Rick Krejci" <apml@ricksastro.com>]

I agree that the M1 could be deeper.  But I didn't have an autoguider, so I
was only taking 80 second unguided subexposures at f/10 at a fl over 2000mm
with an Ha filter, so I was pretty happy with the depth I did get <g>.

Rick

----- Original Message ----- 
From: "Stuart Heggie" <stuart.j.heggie@sympatico.ca>
To: "Discussion of Film Astrophotography" <astro-photo@seds.org>
Sent: Friday, January 09, 2004 4:13 AM
Subject: Re: [APML] Newton-cassegrains: opinions sought


> Rick - the Orion shot is beautiful! The M1 seems a bit thin on signal but
> based on my own attempts, I'd be happy if my autoguider would stop moving
so
> my stars are round!
>
> Stuart Heggie
> http://www3.sympatico.ca/stuart.j.heggie/Stuart.J.Heggie/
> Flesherton, Ontario, Canada
>
> ----- Original Message -----
> From: "Rick Krejci" <apml@ricksastro.com>
> To: "Discussion of Film Astrophotography" <astro-photo@seds.org>
> Sent: Thursday, January 08, 2004 10:20 PM
> Subject: Re: [APML] Newton-cassegrains: opinions sought
>
>
> > I just acquired a CN212 and use it for digital photography.  Here is a
> Canon
> > 10D image using newtonian mode
> >
> > http://www.ricksastro.com/Gallery/htm/10D_M42.htm
> >
> > It is slightly cropped and still shows some elongation in the Corners.
> I'm
> > using the standard (if you can call anything standard in Tak land) Wide
T
> > ring, so I'm assuming the spacing from the corrector should be OK.  I
may
> > need to experiment some.
> >
> > Here is a SXV-H9 CCD image in cassegrain focus with their f9.9 reducer:
> > http://www.ricksastro.com/Gallery/htm/SXV_m1_cn212cat.htm
> >
> > Thus far, after about a month of ownership, I like it quite a bit, but I
> > might be concerned if I were using it for a full 35mm frame in newt
mode.
> > The optics are fantastic, and the focus shift is minimal.  Collimation
is
> > very solid when changing optics and it takes about a minute.  I've had
an
> > 8", 10" and 11" SCT, and I would choose the CN212 over any of them,
mostly
> > for it's flexibility and pinpoint optics.
> >
> > Rick Krejci
> > http://www.ricksastro.com/
> >
> >
> > ----- Original Message -----
> > From: "Emmanuele Sordini" <vega@bloomingstars.com>
> > To: <astro-photo@seds.org>
> > Sent: Thursday, January 08, 2004 4:23 PM
> > Subject: [APML] Newton-cassegrains: opinions sought
> >
> >
> > > Hi all,
> > > searching for a more advanced light bucket than a vanilla SCT, I
thought
> > > about going for a top-quality Newton-Cassegrain (~f/4 - f/15), such as
> the
> > > Tak CN-212 or others. That would make two instruments for the cost of
a
> > > single one. My fields of activity are:
> > >
> > > 1) deep-sky film photography (otherwise, I wouldn't be posting on APML
> > > :-)), and
> > > 2) high-resolution planetary imaging with webcams.
> > >
> > > Anybody have experience with such instruments, especially as compared
to
> > > equally-sized SCTs? I feel that they might be better overall, but with
> > some
> > > drawbacks (less compact, more sensitive to local turbulence, and a
> hassle
> > > to collimate, especially when switching configuration). Furthermore,
> they
> > > don't seem to be very popular among amateur astronomers.
> > >
> > > Any opinion/advice will be highly valued.
> > >
> > > Thanks in advance and clear skies,
> > > Emmanuele Sordini
> > >
> > > _______________________________________________
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> > > Astro-Photo@seds.org
> > > http://seds.org/mailman/listinfo/astro-photo
> > >
> > >
> >
> >
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