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Re: [APML] E200 vs Provia 400F
The only "true" red nebula (H-alpha emission) I see in your links is M8, and it's not so deep as I can expect from such an object. But
maybe it's due to digitalization and elaboration. Even Provia can go deeper.
The other objects are out from my discussion - red nebulas like Nord America and so on.
Do you ever made a side-by-side comparison of E200 vs Provia 400F on such an object?
Lorenzo
Matt BenDaniel wrote:
> See also:
> http://people.ne.mediaone.net/jeboud/m8.htm
> http://people.ne.mediaone.net/jeboud/m51.htm
> http://people.ne.mediaone.net/jeboud/m1.htm
> http://www.astro.ab.psiweb.com/gallery/comet/1996B2/image/masa-o/6b2_325d.jpg
> http://www.jpl.nasa.gov/comet/wain8.html
>
> At 11:24 PM 1/26/2002 +0100, Lorenzo Comolli wrote:
> >The exposures was 30 min. Visual limiting mag was about 6.5 (or little more) at zenith.
> >I've found for my slides (an many of my friends the same) that the square of f/ (for a 400 or 320iso) is good. 20-30% more is the
> >sky is very very dark (2600m). If more, the sky will be too bright.
> >Provia was developed push +1 so 800iso. 8^2/2=64/2=32 min so the exposure is correct for me. The background is a little bright for
> >my taste. In E200 push+2 (and the same 30 min exp) the sky is a little more dark but I would not make a longer exp.
> >
> >The better color balance in your images is maybe due to the same sensitivity of Provia 400F in B and R channels. E200 is maybe the
> >same sensitivity of Provia in B, but 3 times in R. I would use Provia only on M42 because it's very bright, but not on red nebulas.
> >
> >Lorenzo
> >
> >
> >Matt BenDaniel wrote:
> >
> >> How long were the exposures?
> >> What was the limiting visual magnitude?
> >>
> >> At f/8 under dark skies I would expose 400F for two hours, and I would not push. 400F has a much better color balance than E200.
> >>
> >> See:
> >> http://people.ne.mediaone.net/mbendaniel1/gallery/astro/sword.html
> >>
> >> At 10:47 PM 1/26/2002 +0100, Lorenzo Comolli wrote:
> >> >I've seen the comparison of E200 (push+2=640ISO) vs Provia 400F (push+1=800ISO)
> >> >that a friend of mine made with his 80mm f/8 apo, on various red nebulas in the
> >> >same night. The result is clear: NO more Provia 400F on deep sky... the red in
> >> >E200 is 3 times more visible! And the blue is very similar in each images, or a
> >> >little better in E200. Grain is far better in E200.
> >> >
> >> >Why in Japan 400F is so diffused???
> >>
> >> --
> >> Matt BenDaniel
> >> http://starmatt.com
> >>
> >> -- APML Archives at <http://astro.umsystem.edu/apml/> ---
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> >
> >
> >
> >
> >--
> >____________________________________________________________
> >Lorenzo Comolli
> >Internet: http://digilander.iol.it/comolli/
> >E-mail: mailto:comolli@libero.it
> >
> >Socio del Gruppo Astronomico Tradatese
> >Internet: http://gwtradate.tread.it/tradate/gat/
> >____________________________________________________________
> >
> >
> >
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> --
> Matt BenDaniel
> http://starmatt.com
>
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--
____________________________________________________________
Lorenzo Comolli
Internet: http://digilander.iol.it/comolli/
E-mail: mailto:comolli@libero.it
Socio del Gruppo Astronomico Tradatese
Internet: http://gwtradate.tread.it/tradate/gat/
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