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Re: [APML] 7331 (again!)
Rob, Tony, and the group,
I took both images into photodshop for comparison.
I have always thought that there is a small amount of blurry
appearance to the ccd images as well. I think maybe it is the
limit of seeing that is inducing this more so than anything else.
I guess because of my monitor size, the ccd image looks much
better in photoshop than from the link.
I see something that is surprising.
Why is it that the film image actually starts to resolve the smaller galaxy
to the top left better than the ccd image?
Tony- at 200x the image scale of your film image is about equal to Robs
ccd image. If you stack another image or two with these would you
present the image at 200x for comparison. The jpg falls apart with
this amount of magnification in photoshop.
In any event, this is a fun comparison. Both images are superb, and
Tony I'm surprised that the film image is coming along this well
against the 4 hours of ST-10 exposures.
One last question for Rob.
Are the levels adjusted in your image to eliminate the unwanted
light pollution gradients left over from your driveway site?
It would be fun to see your image taken from a very dark site
and the shadow details preserved.
Colt Bednorz
Robert Gendler wrote:
> Bobby,
> You make some very good points. There are some I disagree with
> however. There are HII regions in the CCD image that aren't even
> resolved in Tony's image. Contrast does *NOT* equal detail or resolution.
> In Tony's image the contrast has been dialed up to accentuate the dustlanes
> but again contrast is no substitue for resolution. The detail in the
> dustlanes
> of the CCD image are far superior to that in the film image. Also there's no
> blurring
> at all. The smoothness of the CCD image is solely due to high S/N from
> close to 4 hours of exposure time for the luminance. Tony's image is very
> grainy close up
> because of the relatively poor S/N compared to the CCD image.
> Regards
> Rob Gendler
> Email: robgendler@att.net
> Web site: http://robgendler.astrodigitals.com
>
> ----- Original Message -----
> From: "Bobby Middleton" <bobm@koyote.com>
> To: <astro-photo@seds.org>
> Sent: Saturday, September 22, 2001 10:15 AM
> Subject: Re: [APML] 7331 (again!)
>
> > I can see better points for each image.
> >
> > Tony's film image has better detail of the dust lanes with more contrast
> in
> > them. To see this good look at the smaller face-on satallite galaxie's
> dust
> > lanes at above left of 7331. His stars also don't have the color saturated
> > out. I don't agree with his final colors; I would darken up the image a
> bit
> > while stretching a little more (not much). I would also lower the green in
> > curves just a bit. With these adjustments I like the color of the film a
> bit
> > better than the CCD image. Tony's image also shows the Ha regions much
> > better.
> >
> > Rob's image is of course much better speaking in terms of grain, but
> there's
> > a "fuzziness" there not in the film image. Rob are you doing some kind of
> > moderate blur? Still, with the grain of Tony's image, the CCD image does
> > have a "smoother" look. And Rob does have some of the very faint mag
> stars
> > that Tony does not have; pointing to the sensitivity edge of CCD over
> film.
> >
> > I personally feel that both images are close enough in greatness to leave
> > the final decision up in the air. And with a good TP "L" shot, (or
> > tri-color) the film image could easily surpass the CCD image in quality.
> > Just my subjective opinion. Both are fantastic images!
> > Bobby Middleton
> >
> > "God doesn't play dice".........
> > Albert Einstein on blind chance
> > http://www.koyote.com/users/bobm/astro1.htm
> >
> > ----- Original Message -----
> > From: Robert Gendler <robgendler@worldnet.att.net>
> > To: <astro-photo@seds.org>
> > Sent: Saturday, September 22, 2001 7:42 AM
> > Subject: Re: [APML] 7331 (again!)
> >
> >
> > > Tony,
> > > Really extraordinary effort and great widefield image.
> > > Not quite CCD though. I think with the dimmer detail
> > > CCD still outperforms. Again here is my CCD version
> > > of ngc7331 for comparison.
> > > http://robgendler.astrodigitals.com/7331.html
> > > Rob Gendler
> > > Email: robgendler@att.net
> > > Web site: http://robgendler.astrodigitals.com
> > >
> > > ----- Original Message -----
> > > From: <Tonyhallas@aol.com>
> > > To: <astro-photo@seds.org>
> > > Sent: Saturday, September 22, 2001 12:41 AM
> > > Subject: Re: [APML] 7331 (again!)
> > >
> > >
> > > > Hello everyone,
> > > >
> > > > Last night I used TWO HOUR hypered Kodak Royal Gold 200 @ 90
> minute
> > > exposures of 7331 (great test object) and recorded a LOT more than the
> > > previous negatives. Tracking was very good, as was the focus this time.
> I
> > > "polluted" these better negatives with the original Picture Window
> result
> > > and came up with a new image and a close up.. you can see H II regions
> and
> > > galaxies everywhere... in the close up, the companion galaxy to the
> upper
> > > left even has two faint H II regions showing. As the signal to noise
> ratio
> > > is increased through PW more detail and color is showing up... almost
> CCD!
> > > :-)
> > > >
> > > > You can see these at:
> > > >
> > > > http://www.astrophoto.com/7331.htm
> > > >
> > > > and:
> > > >
> > > > http://www.astrophoto.com/7331CU.htm
> > > >
> > > > Tonight I am taking the LAST images of this galaxy in an attempt
> to
> > > repeat last night's results... then I will have four really good negs to
> > > work from. This has been a real learning experience...
> > > >
> > > > Tony
> > > >
> > > > -- APML Archives at <http://astro.umsystem.edu/apml/> ---
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> > > >
> > >
> > >
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> >
> >
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> >
>
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