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DWB-111 The Propeller Nebula

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  • Dennis Persyk
    DWB-111, a/k/a the Propeller Nebula, is a faint emission nebula in Cygnus. I imaged an LRGB of 50 minute components comprising 5- minuted unguided subframes.
    Message 1 of 8 , Oct 1, 2004
      DWB-111, a/k/a the Propeller Nebula, is a faint emission nebula in
      Cygnus. I imaged an LRGB of 50 minute components comprising 5-
      minuted unguided subframes. Total was 200 minutes, all in one
      night. Takahashi E160 astrograph, MX716 camera and AP1200GTO mount.

      The DWB catalog stands for Dickel, Wendker, and Bieritz, who have
      compiled a somewhat obscure (at least for me) catalog of faint
      emission nebulae in the Cygnus X region.

      I used a log stretch of 0.5 in ImagesPlus followed by curves to
      tease out the nebulosity. I had a faint green gradient which I
      removed in curves by clicking on the green button and selectively
      dimming only the green. I am finding that the green component of
      most DSOs is often not very important and can be reduced in
      intensity without consequence to the image.

      I'd appreciate feedback on my image. This is only my 3rd LRGB and I
      have lots to learn!

      Image at
      http://home.att.net/~dpersyk/new.htm

      Thank you for visiting my site.

      Clear skies,

      Dennis Persyk
      Igloo Observatory Home Page http://dpersyk.home.att.net
      Hampshire, IL
    • rdcrisp
      ... that s a very neat and obscure object Dennis. I like it. Thanks for sharing. Richard
      Message 2 of 8 , Oct 1, 2004
        --- In ccd-newastro@yahoogroups.com, "Dennis Persyk" <dpersyk@a...>
        wrote:
        > DWB-111, a/k/a the Propeller Nebula, is a faint emission nebula in
        > Cygnus. I imaged an LRGB of 50 minute components comprising 5-
        > minuted unguided subframes. Total was 200 minutes, all in one
        > night. Takahashi E160 astrograph, MX716 camera and AP1200GTO mount.
        >
        > The DWB catalog stands for Dickel, Wendker, and Bieritz, who have
        > compiled a somewhat obscure (at least for me) catalog of faint
        > emission nebulae in the Cygnus X region.

        that's a very neat and obscure object Dennis. I like it. Thanks for
        sharing.
        Richard
      • Randy Nulman
        Nice Dennis! There are still some gradient issues in the image, and I would suggest using Ron s PS technique (or his software...or Maxim s gradient removal
        Message 3 of 8 , Oct 1, 2004
          Nice Dennis!

          There are still some gradient issues in the image, and I would
          suggest using Ron's PS technique (or his software...or Maxim's
          gradient removal tool) to deal with the gradients vs. just basically
          clipping the green channel...you will like the results better.

          Nice to see you continuing in color...each image keeps getting
          better!

          Regards,
          Randy Nulman


          --- In ccd-newastro@yahoogroups.com, "Dennis Persyk" <dpersyk@a...>
          wrote:
          > DWB-111, a/k/a the Propeller Nebula, is a faint emission nebula in
          > Cygnus. I imaged an LRGB of 50 minute components comprising 5-
          > minuted unguided subframes. Total was 200 minutes, all in one
          > night. Takahashi E160 astrograph, MX716 camera and AP1200GTO mount.
          >
          > The DWB catalog stands for Dickel, Wendker, and Bieritz, who have
          > compiled a somewhat obscure (at least for me) catalog of faint
          > emission nebulae in the Cygnus X region.
          >
          > I used a log stretch of 0.5 in ImagesPlus followed by curves to
          > tease out the nebulosity. I had a faint green gradient which I
          > removed in curves by clicking on the green button and selectively
          > dimming only the green. I am finding that the green component of
          > most DSOs is often not very important and can be reduced in
          > intensity without consequence to the image.
          >
          > I'd appreciate feedback on my image. This is only my 3rd LRGB and
          I
          > have lots to learn!
          >
          > Image at
          > http://home.att.net/~dpersyk/new.htm
          >
          > Thank you for visiting my site.
          >
          > Clear skies,
          >
          > Dennis Persyk
          > Igloo Observatory Home Page http://dpersyk.home.att.net
          > Hampshire, IL
        • Dennis Persyk
          Hi Randy, Thanks for the input. I applied a planar background compensation operator in ImagesPlus to the green gradient in the upper right corner. It is not
          Message 4 of 8 , Oct 1, 2004
            Hi Randy,

            Thanks for the input. I applied a planar background compensation
            operator in ImagesPlus to the green gradient in the upper right
            corner. It is not perfect yet but I think it is better now.
            http://home.att.net/~dpersyk/new.htm

            Color gradients are the bane of LRGB images!

            Clear skies,

            Dennis
            Igloo Observatory Home Page http://dpersyk.home.att.net
            Hampshire, IL


            --- In ccd-newastro@yahoogroups.com, "Randy Nulman" <rj.nulman@v...>
            wrote:
            > Nice Dennis!
            >
            > There are still some gradient issues in the image, and I would
            > suggest using Ron's PS technique (or his software...or Maxim's
            > gradient removal tool) to deal with the gradients vs. just
            basically clipping the green channel...you will like the results
            better.
            >
            > Nice to see you continuing in color...each image keeps getting
            > better!
            >
            > Regards,
            > Randy Nulman
            >
            >
            > --- In ccd-newastro@yahoogroups.com, "Dennis Persyk"
            <dpersyk@a...>
            > wrote:
            > > DWB-111, a/k/a the Propeller Nebula, is a faint emission nebula
            in Cygnus. I imaged an LRGB of 50 minute components comprising 5-
            > > minuted unguided subframes. Total was 200 minutes, all in one
            > > night. Takahashi E160 astrograph, MX716 camera and AP1200GTO
            mount.
            > >
            > > The DWB catalog stands for Dickel, Wendker, and Bieritz, who
            have compiled a somewhat obscure (at least for me) catalog of faint
            > > emission nebulae in the Cygnus X region.
            > >
            > > I used a log stretch of 0.5 in ImagesPlus followed by curves to
            > > tease out the nebulosity. I had a faint green gradient which I
            > > removed in curves by clicking on the green button and
            selectively dimming only the green. I am finding that the green
            component of most DSOs is often not very important and can be
            reduced in intensity without consequence to the image.
            > >
            > > I'd appreciate feedback on my image. This is only my 3rd LRGB
            and I have lots to learn!
            > >
            > > Image at
            > > http://home.att.net/~dpersyk/new.htm
            > >
            > > Thank you for visiting my site.
            > >
            > > Clear skies,
            > >
            > > Dennis Persyk
            > > Igloo Observatory Home Page http://dpersyk.home.att.net
            > > Hampshire, IL
          • Randy Nulman
            Much improved, Dennis! The gradient issue is much better. I took it into PS (because it looked a little dark and cut-off ) to me. It is a bit clipped ...if
            Message 5 of 8 , Oct 1, 2004
              Much improved, Dennis!
              The gradient issue is much better. I took it into PS (because it
              looked a little dark and "cut-off") to me. It is a
              bit "clipped"...if you can re-process this so that the nebula is
              not "abruptly" cut-off from the clipping, you will be
              happier...guess it's just a matter of how much of the remaining
              gradients will show...goal is a smooth and gradual transition from
              the faint areas of the nebula into the background.

              Randy Nulman


              --- In ccd-newastro@yahoogroups.com, "Dennis Persyk" <dpersyk@a...>
              wrote:
              > Hi Randy,
              >
              > Thanks for the input. I applied a planar background compensation
              > operator in ImagesPlus to the green gradient in the upper right
              > corner. It is not perfect yet but I think it is better now.
              > http://home.att.net/~dpersyk/new.htm
              >
              > Color gradients are the bane of LRGB images!
              >
              > Clear skies,
              >
              > Dennis
              > Igloo Observatory Home Page http://dpersyk.home.att.net
              > Hampshire, IL
              >
              >
              > --- In ccd-newastro@yahoogroups.com, "Randy Nulman"
              <rj.nulman@v...>
              > wrote:
              > > Nice Dennis!
              > >
              > > There are still some gradient issues in the image, and I would
              > > suggest using Ron's PS technique (or his software...or Maxim's
              > > gradient removal tool) to deal with the gradients vs. just
              > basically clipping the green channel...you will like the results
              > better.
              > >
              > > Nice to see you continuing in color...each image keeps getting
              > > better!
              > >
              > > Regards,
              > > Randy Nulman
              > >
              > >
              > > --- In ccd-newastro@yahoogroups.com, "Dennis Persyk"
              > <dpersyk@a...>
              > > wrote:
              > > > DWB-111, a/k/a the Propeller Nebula, is a faint emission
              nebula
              > in Cygnus. I imaged an LRGB of 50 minute components comprising 5-
              > > > minuted unguided subframes. Total was 200 minutes, all in one
              > > > night. Takahashi E160 astrograph, MX716 camera and AP1200GTO
              > mount.
              > > >
              > > > The DWB catalog stands for Dickel, Wendker, and Bieritz, who
              > have compiled a somewhat obscure (at least for me) catalog of
              faint
              > > > emission nebulae in the Cygnus X region.
              > > >
              > > > I used a log stretch of 0.5 in ImagesPlus followed by curves
              to
              > > > tease out the nebulosity. I had a faint green gradient which
              I
              > > > removed in curves by clicking on the green button and
              > selectively dimming only the green. I am finding that the green
              > component of most DSOs is often not very important and can be
              > reduced in intensity without consequence to the image.
              > > >
              > > > I'd appreciate feedback on my image. This is only my 3rd LRGB
              > and I have lots to learn!
              > > >
              > > > Image at
              > > > http://home.att.net/~dpersyk/new.htm
              > > >
              > > > Thank you for visiting my site.
              > > >
              > > > Clear skies,
              > > >
              > > > Dennis Persyk
              > > > Igloo Observatory Home Page http://dpersyk.home.att.net
              > > > Hampshire, IL
            • Wodaski Yahoo
              That went a long way toward improving the image. If you d like to dig a little deeper, I think the gradient is still forcing an unnaturally high black point in
              Message 6 of 8 , Oct 1, 2004
                That went a long way toward improving the image. If you'd like to dig a
                little deeper, I think the gradient is still forcing an unnaturally high
                black point in the color channels; I think you might be able to improve this
                even more.


                Ron Wodaski
                The New CCD Astronomy
                http://www.newastro.com/ipb

                -----Original Message-----
                From: Dennis Persyk [mailto:dpersyk@...]
                Sent: Friday, October 01, 2004 6:02 PM
                To: ccd-newastro@yahoogroups.com
                Subject: [ccd-newastro] Re: DWB-111 The Propeller Nebula


                Hi Randy,

                Thanks for the input. I applied a planar background compensation
                operator in ImagesPlus to the green gradient in the upper right
                corner. It is not perfect yet but I think it is better now.
                http://home.att.net/~dpersyk/new.htm

                Color gradients are the bane of LRGB images!

                Clear skies,

                Dennis
                Igloo Observatory Home Page http://dpersyk.home.att.net
                Hampshire, IL


                --- In ccd-newastro@yahoogroups.com, "Randy Nulman" <rj.nulman@v...>
                wrote:
                > Nice Dennis!
                >
                > There are still some gradient issues in the image, and I would
                > suggest using Ron's PS technique (or his software...or Maxim's
                > gradient removal tool) to deal with the gradients vs. just
                basically clipping the green channel...you will like the results
                better.
                >
                > Nice to see you continuing in color...each image keeps getting
                > better!
                >
                > Regards,
                > Randy Nulman
                >
                >
                > --- In ccd-newastro@yahoogroups.com, "Dennis Persyk"
                <dpersyk@a...>
                > wrote:
                > > DWB-111, a/k/a the Propeller Nebula, is a faint emission nebula
                in Cygnus. I imaged an LRGB of 50 minute components comprising 5-
                > > minuted unguided subframes. Total was 200 minutes, all in one
                > > night. Takahashi E160 astrograph, MX716 camera and AP1200GTO
                mount.
                > >
                > > The DWB catalog stands for Dickel, Wendker, and Bieritz, who
                have compiled a somewhat obscure (at least for me) catalog of faint
                > > emission nebulae in the Cygnus X region.
                > >
                > > I used a log stretch of 0.5 in ImagesPlus followed by curves to
                > > tease out the nebulosity. I had a faint green gradient which I
                > > removed in curves by clicking on the green button and
                selectively dimming only the green. I am finding that the green
                component of most DSOs is often not very important and can be
                reduced in intensity without consequence to the image.
                > >
                > > I'd appreciate feedback on my image. This is only my 3rd LRGB
                and I have lots to learn!
                > >
                > > Image at
                > > http://home.att.net/~dpersyk/new.htm
                > >
                > > Thank you for visiting my site.
                > >
                > > Clear skies,
                > >
                > > Dennis Persyk
                > > Igloo Observatory Home Page http://dpersyk.home.att.net
                > > Hampshire, IL






                Yahoo! Groups Links









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              • Dennis Persyk
                Thanks for checking out the image, Ron. I can see that the background is too black and the histogram is severely clipped but I don t know how to fix it. I
                Message 7 of 8 , Oct 1, 2004
                  Thanks for checking out the image, Ron. I can see that the
                  background is too black and the histogram is severely clipped but I
                  don't know how to fix it. I started working with the image after the
                  LRGB combine in Maxim and perhaps I need to work on the individual
                  LRGB channels first before combining?

                  Clear skies,

                  Dennis

                  --- In ccd-newastro@yahoogroups.com, "Wodaski Yahoo" <yahoo@n...>
                  wrote:
                  > That went a long way toward improving the image. If you'd like to
                  dig a little deeper, I think the gradient is still forcing an
                  unnaturally high black point in the color channels; I think you
                  might be able to improve this even more.
                  >
                  >
                  > Ron Wodaski
                  > The New CCD Astronomy
                  > http://www.newastro.com/ipb
                  >
                  > -----Original Message-----
                  > From: Dennis Persyk [mailto:dpersyk@a...]
                  > Sent: Friday, October 01, 2004 6:02 PM
                  > To: ccd-newastro@yahoogroups.com
                  > Subject: [ccd-newastro] Re: DWB-111 The Propeller Nebula
                  >
                  >
                  > Hi Randy,
                  >
                  > Thanks for the input. I applied a planar background compensation
                  > operator in ImagesPlus to the green gradient in the upper right
                  > corner. It is not perfect yet but I think it is better now.
                  > http://home.att.net/~dpersyk/new.htm
                  >
                  > Color gradients are the bane of LRGB images!
                  >
                  > Clear skies,
                  >
                  > Dennis
                  > Igloo Observatory Home Page http://dpersyk.home.att.net
                  > Hampshire, IL
                  >
                  >
                  > --- In ccd-newastro@yahoogroups.com, "Randy Nulman"
                  <rj.nulman@v...>
                  > wrote:
                  > > Nice Dennis!
                  > >
                  > > There are still some gradient issues in the image, and I would
                  > > suggest using Ron's PS technique (or his software...or Maxim's
                  > > gradient removal tool) to deal with the gradients vs. just
                  > basically clipping the green channel...you will like the results
                  > better.
                  > >
                  > > Nice to see you continuing in color...each image keeps getting
                  > > better!
                  > >
                  > > Regards,
                  > > Randy Nulman
                  > >
                  > >
                  > > --- In ccd-newastro@yahoogroups.com, "Dennis Persyk"
                  > <dpersyk@a...>
                  > > wrote:
                  > > > DWB-111, a/k/a the Propeller Nebula, is a faint emission
                  nebula in Cygnus. I imaged an LRGB of 50 minute components
                  comprising 5- minuted unguided subframes. Total was 200 minutes,
                  all in one night. Takahashi E160 astrograph, MX716 camera and
                  AP1200GTO
                  > mount.
                  > > >
                  > > > The DWB catalog stands for Dickel, Wendker, and Bieritz, who
                  > have compiled a somewhat obscure (at least for me) catalog of
                  faint emission nebulae in the Cygnus X region.
                  > > >
                  > > > I used a log stretch of 0.5 in ImagesPlus followed by curves
                  to tease out the nebulosity. I had a faint green gradient which I
                  > > > removed in curves by clicking on the green button and
                  > selectively dimming only the green. I am finding that the green
                  > component of most DSOs is often not very important and can be
                  > reduced in intensity without consequence to the image.
                  > > >
                  > > > I'd appreciate feedback on my image. This is only my 3rd LRGB
                  > and I have lots to learn!
                  > > >
                  > > > Image at
                  > > > http://home.att.net/~dpersyk/new.htm
                  > > >
                  > > > Thank you for visiting my site.
                  > > >
                  > > > Clear skies,
                  > > >
                  > > > Dennis Persyk
                  > > > Igloo Observatory Home Page http://dpersyk.home.att.net
                  > > > Hampshire, IL
                  >
                • Wodaski Yahoo
                  I don t generally work on the individual images, but there are some limited times when it makes sense to do so. I generally do this in Photoshop _after_
                  Message 8 of 8 , Oct 1, 2004
                    I don't generally work on the individual images, but there are some limited
                    times when it makes sense to do so. I generally do this in Photoshop _after_
                    combining color; Photoshop lets me work on one channel at a time if I wish
                    to.

                    I have a routine that I use which involves some steps that are not commonly
                    talked about, but they become important when you are working with gradients.

                    Here's the high-level breakdown. I first presented this at the Astroimage
                    conference in Southern California in August. A few days before I gave the
                    presentation, I came up with a new way to look at color balancing, involving
                    four steps instead of one.

                    Step one: remove color bias. This is the step where one deals with gradients
                    and brighter backgrounds in one color than another. I referred to this as a
                    normalization step earlier, but I think that "color bias" is a more accurate
                    term for referring to what's going on. If one color has a brighter
                    background than the others, you can use black points _on the individual
                    channels_ to match the background levels. This will neutralize the
                    background, removing any color bias.

                    What this won't do is correct a gradient. But a gradient does create a form
                    of color bias, as you can see in your image with the green channel. In the
                    case of a gradient, only a _portion_ of the image has a color bias. By using
                    selections (or other tools) to remove the gradient, you correct the color
                    bias from the gradient.

                    The important key is to realize that removing the bias due to gradient and
                    the actual color bias (where the entire channel has a brighter background)
                    are two different steps. I would recommend removing gradients before
                    attempting to correct color bias.

                    Once the background is neutral, then you can deal with the other steps:

                    * Color balancing (I use what I call the pseudo white point, the place in
                    the histogram where the curve drops nearly to zero), plus knowledge of the
                    color and structure of the object in the image.
                    * Color Saturation adjustments
                    * Color Noise considerations (do any of the colors have too much noise to be
                    properly represented in the image? If yes, you have to drop back the color
                    saturation. Color Noise represents the limit to what you can achieve with
                    the color data.)

                    That's just an outline, but there's a lot of information behind all of this,
                    which is covered in detail in the new book. It's partly a new way of
                    thinking about color overall, and partly just a breakdown into more logical
                    (and better-named) pieces.


                    Ron Wodaski
                    The New CCD Astronomy
                    http://www.newastro.com/ipb

                    -----Original Message-----
                    From: Dennis Persyk [mailto:dpersyk@...]
                    Sent: Friday, October 01, 2004 10:33 PM
                    To: ccd-newastro@yahoogroups.com
                    Subject: [ccd-newastro] Re: DWB-111 The Propeller Nebula


                    Thanks for checking out the image, Ron. I can see that the
                    background is too black and the histogram is severely clipped but I
                    don't know how to fix it. I started working with the image after the
                    LRGB combine in Maxim and perhaps I need to work on the individual
                    LRGB channels first before combining?

                    Clear skies,

                    Dennis

                    --- In ccd-newastro@yahoogroups.com, "Wodaski Yahoo" <yahoo@n...>
                    wrote:
                    > That went a long way toward improving the image. If you'd like to
                    dig a little deeper, I think the gradient is still forcing an
                    unnaturally high black point in the color channels; I think you
                    might be able to improve this even more.
                    >
                    >
                    > Ron Wodaski
                    > The New CCD Astronomy
                    > http://www.newastro.com/ipb
                    >
                    > -----Original Message-----
                    > From: Dennis Persyk [mailto:dpersyk@a...]
                    > Sent: Friday, October 01, 2004 6:02 PM
                    > To: ccd-newastro@yahoogroups.com
                    > Subject: [ccd-newastro] Re: DWB-111 The Propeller Nebula
                    >
                    >
                    > Hi Randy,
                    >
                    > Thanks for the input. I applied a planar background compensation
                    > operator in ImagesPlus to the green gradient in the upper right
                    > corner. It is not perfect yet but I think it is better now.
                    > http://home.att.net/~dpersyk/new.htm
                    >
                    > Color gradients are the bane of LRGB images!
                    >
                    > Clear skies,
                    >
                    > Dennis
                    > Igloo Observatory Home Page http://dpersyk.home.att.net
                    > Hampshire, IL
                    >
                    >
                    > --- In ccd-newastro@yahoogroups.com, "Randy Nulman"
                    <rj.nulman@v...>
                    > wrote:
                    > > Nice Dennis!
                    > >
                    > > There are still some gradient issues in the image, and I would
                    > > suggest using Ron's PS technique (or his software...or Maxim's
                    > > gradient removal tool) to deal with the gradients vs. just
                    > basically clipping the green channel...you will like the results
                    > better.
                    > >
                    > > Nice to see you continuing in color...each image keeps getting
                    > > better!
                    > >
                    > > Regards,
                    > > Randy Nulman
                    > >
                    > >
                    > > --- In ccd-newastro@yahoogroups.com, "Dennis Persyk"
                    > <dpersyk@a...>
                    > > wrote:
                    > > > DWB-111, a/k/a the Propeller Nebula, is a faint emission
                    nebula in Cygnus. I imaged an LRGB of 50 minute components
                    comprising 5- minuted unguided subframes. Total was 200 minutes,
                    all in one night. Takahashi E160 astrograph, MX716 camera and
                    AP1200GTO
                    > mount.
                    > > >
                    > > > The DWB catalog stands for Dickel, Wendker, and Bieritz, who
                    > have compiled a somewhat obscure (at least for me) catalog of
                    faint emission nebulae in the Cygnus X region.
                    > > >
                    > > > I used a log stretch of 0.5 in ImagesPlus followed by curves
                    to tease out the nebulosity. I had a faint green gradient which I
                    > > > removed in curves by clicking on the green button and
                    > selectively dimming only the green. I am finding that the green
                    > component of most DSOs is often not very important and can be
                    > reduced in intensity without consequence to the image.
                    > > >
                    > > > I'd appreciate feedback on my image. This is only my 3rd LRGB
                    > and I have lots to learn!
                    > > >
                    > > > Image at
                    > > > http://home.att.net/~dpersyk/new.htm
                    > > >
                    > > > Thank you for visiting my site.
                    > > >
                    > > > Clear skies,
                    > > >
                    > > > Dennis Persyk
                    > > > Igloo Observatory Home Page http://dpersyk.home.att.net
                    > > > Hampshire, IL
                    >







                    Yahoo! Groups Links









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