Re: [APML] O.T.: Alternatives to Film and CCD

["Jim Vineyard" <deepskyphotos@hotmail.com>]

Hap,
  You wrote:

> You can go pretty deep with DSLR's...just stack a boatload of 5 minute
> exposures.  Let me know what you think of my 4 hour Horsehead region shot 
> at
> http://www.machunter.org/hap_alnitak_close.html .  This is 48 5-minute
> images aligned and stacked for 4 hours of total exposure.

  Well, in a word what I think is: "Yummy"

  That, and you've probably been having a lot more fun than me over the last 
year in astro-photography/imaging!  Yes I know these cameras are capable of 
these kinds of results and I think your latter S/N explanation was far 
better than I could have pulled together concisely.  I probably would have 
gone off on some tangent about things I don't fully understand such as 
reaching something like "full well depth" etc on a faint object and just dug 
myself into a hole.  But really we both understand the guys with cooled 
CCD's can go deeper by exposing longer.
  I was impressed that the Meade 0.63x could be used on this scope and chip 
combo, shocked actually, since I owned one too a long while ago and as we 
know the vignetting is pretty terrible on 35mm film, and I had thought it 
was designed only for SCT's.
  I'm not sure the Televue Reducer/Corrector would work any better.  All I 
can relay about the Televue is it appears very touchy about its lens spacing 
from the surface of the film plane, does vignette moderately on 35mm, and 
also must be exactly square in the focusing tube to give quality apo 
results.  I found I pretty much HAD to replace the drawtube collar, with 
it's two set screws with one offered by scopestuff, well right here actually 
and $35 at the time:

http://www.scopestuff.com/ss_fas2.htm

  It locks with a compression ring rather than set screws.  If you get to 
try a Televue I'd love to hear the results (e-mail me privately or sneak it 
into an O.T. on-list) since I already have the one I'm using with the ED80 
for film.  This was the only modification I needed on the ED80.  The focuser 
had no play in it and the optics were the best I've ever personally seen. 
Seemed to be damned near textbook in my particular sample according to a 
good Ronchi testing and star testing while carefully examining Suiter's 
book, this after an important and good thorough cool down.
  The nice thing is I could pick up a Canon this month if I really decide 
to.  Perhaps you can tell I've been contemplating it.  I really think I'd 
like to be able to shoot daylight though and might just settle for a 
non-modified camera even with the trade-offs involved.  But then there is 
that new ST-402 thing lurking out there.  BTW, I've heard mention someone is 
writing a book on DSLR imaging.

Info ALWAYS helps!

Jim Vineyard



----- Original Message ----- 
From: "Hap Griffin" <lgriffin@sc.rr.com>
To: "Discussion of Film Astrophotography" <astro-photo@seds.org>
Sent: Sunday, December 26, 2004 5:55 PM
Subject: Re: [APML] O.T.: Alternatives to Film and CCD


> Answers below:
>
> ----- Original Message ----- 
> From: "Jim Vineyard" <deepskyphotos@hotmail.com>
> To: "Discussion of Film Astrophotography" <astro-photo@seds.org>
> Sent: Sunday, December 26, 2004 6:51 PM
> Subject: Re: [APML] O.T.: Alternatives to Film and CCD
>
>
> > Hello Hap,
> >   Not to step in on Michael's original question.  Which I'd say no, 
> > there
> > are no alternatives to film, or a full astro-dedicated CCD, to be
> > bought/made (other than maybe the little "Totally Autostar Proprietary"
> > Meade "Deep Sky Imager" or a useless still-film-based pinhole camera!)
> other
> > than the DSLR.  But I also think there will be useable astro-films 
> > around
> > for quite some time yet.
> >
> >   But Hap, I've been looking at most of your DSLR images over the last
> > several months and have been wondering if there is a known technical
> reason
> > why you chose to go with the "Meade 0.63x Focal Reducer/Corrector" over
> say
> > the "Tele Vue 0.8x Reducer/Corrector" for use with your Orion ED80?  Did
> you
> > just have the Meade unit on hand, is it just the cost differential for
> equal
> > performance, or is it superior in some way to the Tele Vue for use with
> the
> > ED80 and a Canon DSLR?  I was surprised to see the Meade unit noted, and
> > clearly very useable.
> >
>
> The main reason I went with the Meade was the price.  However, I do see 
> some
> coma in the corners with it and will soon be trying out my imaging 
> partner's
> Televue 0.8x reducer.  If it works better, I'll spring for one.
>
> >   The main reasons I haven't snapped up a Canon DSLR is the constant and
> > fast-paced innovation in digital cameras in general i.e. I don't want an
> > obsolete model in a year or so as I have in a digital point & shoot. 
> > And
> > also I'm a little put off by not being able to go really deep with a 
> > DSLR.
> > I may wait, for the what is it, the SBIG Model ST-402 due to start
> shipping
> > anytime soon.
> >
>
> You can go pretty deep with DSLR's...just stack a boatload of 5 minute
> exposures.  Let me know what you think of my 4 hour Horsehead region shot 
> at
> http://www.machunter.org/hap_alnitak_close.html .  This is 48 5-minute
> images aligned and stacked for 4 hours of total exposure.
>
> >   But anyway, is there a real advantage to the Meade 0.63x over the Tele
> Vue
> > model with the ED80 that you know of?
> >
>
> No, and I'm pretty sure the Televue is the better unit.  Will try one 
> soon.
>
> > Thanks for any info,
> >
> > Jim Vineyard
> > www.deepskyphotos.com
> >
>
> Clear skies!
>
> Hap Griffin
> www.machunter.org/hapspics.html
> www.hapg.org/astrocables.htm
>
> _______________________________________________
> Astro-Photo mailing list
> Astro-Photo@seds.org
> http://seds.org/mailman/listinfo/astro-photo
> 
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