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Re: Cocoon Nebula

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  • Rick Yandrick
    Randy: Thanks for the comments. It s such an interesting object, and was a lot easier to image last year with a TAK FSQ106, vs. the longer focal length
    Message 1 of 18 , Aug 1, 2003
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      Randy:

      Thanks for the comments. It's such an interesting object, and was a
      lot easier to image last year with a TAK FSQ106, vs. the longer
      focal length instrument this year. I found the nebula really needed
      to be teased out a bit, more than I thought it would !

      Rick Yandrick
      www.cosminimage.com


      --- In ccd-newastro@yahoogroups.com, "Randy Nulman" <rj.nulman@v...>
      wrote:
      > Rick,
      > I think it's a beautiful image..great colors in both the nebula
      and
      > the stars...I especially like "subtle" look to the nebula vs. some
      of
      > the "harsher" looks I've seen in other versions. Also the blue
      > fringe shows nicely...you did great with that "bag of tricks" you
      > thru into the processing!
      >
      > Randy Nulman
      >
      > --- In ccd-newastro@yahoogroups.com, "Rick Yandrick" <rick@a...>
      > wrote:
      > > Hi All:
      > >
      > > I haven't posted here for a while...because with the weather,
      > > imaging had been lousy for a while.
      > > Anyway, here's a post of the Cocoon I took last night....which I
      > > found the processing of to be extremely challenging (trying to
      > > handle the blue color).
      > >
      > > 75 Minutes LUM on 8" Cassegrain @ F/6.4, Astronomik filters, SX
      > > HX916 camera, curves and levels in photoshop, along with any
      other
      > > tricks I could figure out to throw at it. Not the greatest image
      of
      > > the cocoon, but was such a challenge I decided to post it.
      > >
      > > http://www.cosmicimage.com/Cocoon-75-Min-Small.jpg
      > >
      > > Processing suggestions always welcome...
      > >
      > > Rick Yandrick
      > > www.cosmicimage.com
    • Mike Fleenor
      Rick, This is a great image! I have not seen that much regarding the Vixen Cassegrain before. How well does it hold collimation? Also how often do you have to
      Message 2 of 18 , Aug 1, 2003
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        Rick,

        This is a great image!

        I have not seen that much regarding the Vixen Cassegrain before. How
        well does it hold collimation? Also how often do you have to refocus
        due to thermal contraction over the night?

        Thanks,

        Mike
      • Rick Yandrick
        Mike: I like this little scope. I have had very little issue with focus changing through an evening. In fact, I have a robofocus mounted on it, and it s rare
        Message 3 of 18 , Aug 1, 2003
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          Mike:

          I like this little scope. I have had very little issue with focus
          changing through an evening. In fact, I have a robofocus mounted on
          it, and it's rare that I need to focus from one session to the next,
          and this is at F/6.4 ! I must say I enjoy focusing a scope with
          diffraction spikes...certainly makes it easier. I have automated
          focus software, but such a pleasure to focus that I don't bother
          with it.

          Collimation holds very well. I will say that an 8" scope is
          forgiving in terms of thermals, etc., by virtue of a smaller mirror
          mass, smaller tube, etc. I would really like to see a 10" version of
          this scope, but it's relatively new over here in the U.S., so not
          too common.

          It's a bit less forgiving than an SCT for backfocus, availability of
          accessories, etc., but not impossible. It took a few adapters from
          Hutech and John C. at Adirondack Video to enable me to attach my
          F/6.4 reducer, filter wheel, and HX camera within limits, but it's
          done ! I'll be posting info on this combo at my website soon
          enough...I'm currently busy working out a RA issue on my mount, then
          I can focus on the website a bit.

          IMHO some advantages of the scope are:
          Stationary mirror...needless to say this is awesome.
          Solid on collimation (so far)
          A nice FLAT field....another needless to say awesome
          Fast cooldown - open tube (real fast...again, the small 8" size
          helps)
          No dewing of the corrector
          CHEAP price for the scope
          In terms of ease of use, it smokes my SCT on all issues. (Although
          an 8" SCT may have slightly better contrast due to smaller secondary)

          some disadvantages are:
          Focuser has the field flattener built into the front end of it, so
          focuser can't be upgraded
          Backfocus is not as deep as a SCT (not a problem...just need to plan)
          Adapters and accessories are not as readliy available as in the SCT
          world

          Hope info helps !

          Rick Yandrick
          www.cosmicimage.com




          --- In ccd-newastro@yahoogroups.com, "Mike Fleenor"
          <mike_from_tn@y...> wrote:
          > Rick,
          >
          > This is a great image!
          >
          > I have not seen that much regarding the Vixen Cassegrain before.
          How
          > well does it hold collimation? Also how often do you have to
          refocus
          > due to thermal contraction over the night?
          >
          > Thanks,
          >
          > Mike
        • Dennis Persyk
          I imaged IC5146, the Cocoon Nebula for 72 minutes. The image is an RGB of 24 minutes per component, each component a sum of 4-minute unguided frames.
          Message 4 of 18 , Sep 18, 2004
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            I imaged IC5146, the Cocoon Nebula for 72 minutes. The image is an
            RGB of 24 minutes per component, each component a sum of 4-minute
            unguided frames. Takahashi E160 f/3.3 astrograph, AP1200GTO, MX716
            and True Technology filters.

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

            Questions:
            1) What causes the red halos around stars?
            2) Is there a way to mitigate them in processing?

            Thanks for the help.

            Clear skies,

            Dennis Persyk
            Igloo Observatory Home Page http://dpersyk.home.att.net
            Hampshire, IL
          • Paul K
            Hi Dennis, Nice shot! You may want to consider adding some luminance or Ha or even just more Red frames as luminance to smooth out the image a bit. The red
            Message 5 of 18 , Sep 19, 2004
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              Hi Dennis,

              Nice shot! You may want to consider adding some luminance or Ha or
              even just more Red frames as luminance to smooth out the image a bit.

              The red halos can be caused by a slight focus difference between red
              and other filters. Do you refocus between filters? At small F/
              ratios, my Astronomik filters also exhibit the need to refocus.

              The blue halos are most likely due to some filter reflections off of
              the bright stars.

              There are some tricks in Photoshop using the minimum filter and/or
              star selection that let you reduce the effect. I'm not sure if these
              are available in ImagesPlus.

              Regards,

              -Paul


              --- In ccd-newastro@yahoogroups.com, "Dennis Persyk" <dpersyk@a...>
              wrote:
              > I imaged IC5146, the Cocoon Nebula for 72 minutes. The image is
              an
              > RGB of 24 minutes per component, each component a sum of 4-minute
              > unguided frames. Takahashi E160 f/3.3 astrograph, AP1200GTO, MX716
              > and True Technology filters.
              >
              > Image at
              > http://home.att.net/~dpersyk/new.htm
              >
              > Questions:
              > 1) What causes the red halos around stars?
              > 2) Is there a way to mitigate them in processing?
              >
              > Thanks for the help.
              >
              > Clear skies,
              >
              > Dennis Persyk
              > Igloo Observatory Home Page http://dpersyk.home.att.net
              > Hampshire, IL
            • Dennis Persyk
              Hi Paul, Thanks for the feedback. I am starting to take luminance frames now and they help a lot. I do refocus frequently as the E160 has a large
              Message 6 of 18 , Sep 19, 2004
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                Hi Paul,

                Thanks for the feedback. I am starting to take luminance frames now
                and they help a lot.

                I do refocus frequently as the E160 has a large d(focus)/d(temp)
                derivative. A carbon tube would probably benefit this scope
                considerably.

                I also have PS CS but don't know how to use it! If you could post a
                checklist for your technique in PS I'd like to give it a try.

                Clear skies,

                Dennis

                --- In ccd-newastro@yahoogroups.com, "Paul K" <paul@p...> wrote:
                > Hi Dennis,
                >
                > Nice shot! You may want to consider adding some luminance or Ha or
                > even just more Red frames as luminance to smooth out the image a
                bit.
                >
                > The red halos can be caused by a slight focus difference between
                red and other filters. Do you refocus between filters? At small F/
                > ratios, my Astronomik filters also exhibit the need to refocus.
                >
                > The blue halos are most likely due to some filter reflections off
                of the bright stars.
                >
                > There are some tricks in Photoshop using the minimum filter and/or
                > star selection that let you reduce the effect. I'm not sure if
                these are available in ImagesPlus.
                >
                > Regards,
                >
                > -Paul
                >
                >
                > --- In ccd-newastro@yahoogroups.com, "Dennis Persyk"
                <dpersyk@a...>
                > wrote:
                > > I imaged IC5146, the Cocoon Nebula for 72 minutes. The image
                is an RGB of 24 minutes per component, each component a sum of 4-
                minute unguided frames. Takahashi E160 f/3.3 astrograph,
                AP1200GTO, MX716 and True Technology filters.
                > >
                > > Image at
                > > http://home.att.net/~dpersyk/new.htm
                > >
                > > Questions:
                > > 1) What causes the red halos around stars?
                > > 2) Is there a way to mitigate them in processing?
                > >
                > > Thanks for the help.
                > >
                > > Clear skies,
                > >
                > > Dennis Persyk
                > > Igloo Observatory Home Page http://dpersyk.home.att.net
                > > Hampshire, IL
              • Paul K
                Hi Dennis, Already did :-) Here are the two articles that should get you started: http://pk.darkhorizons.org/PSStarBloat.htm
                Message 7 of 18 , Sep 19, 2004
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                  Hi Dennis,

                  Already did :-) Here are the two articles that should get you started:

                  http://pk.darkhorizons.org/PSStarBloat.htm
                  http://pk.darkhorizons.org/stars.htm

                  The first one will helps reduce the star size. In your case, you'll
                  probably want to apply it selectively, just to the red channel.

                  The second article shows how to select just the stars, leaving the
                  nebulosity untouched. Once you do this, you could use the minimum
                  filter, as in the first article, try an Unsharp mask to reduce star
                  size, or even just reduce red color saturation.

                  Another possibility is to select the difference between the stars in
                  red channel, and say, the green. Then, you could simply reduce the
                  red color saturation, making the red flares into a more neutral
                  color, or use curves/levels to make the red flares less bright.

                  Regards,

                  -Paul

                  --- In ccd-newastro@yahoogroups.com, "Dennis Persyk" <dpersyk@a...>
                  wrote:
                  > Hi Paul,
                  >
                  > Thanks for the feedback. I am starting to take luminance frames
                  now
                  > and they help a lot.
                  >
                  > I do refocus frequently as the E160 has a large d(focus)/d(temp)
                  > derivative. A carbon tube would probably benefit this scope
                  > considerably.
                  >
                  > I also have PS CS but don't know how to use it! If you could post
                  a
                  > checklist for your technique in PS I'd like to give it a try.
                  >
                  > Clear skies,
                  >
                  > Dennis
                  >
                  > --- In ccd-newastro@yahoogroups.com, "Paul K" <paul@p...> wrote:
                  > > Hi Dennis,
                  > >
                  > > Nice shot! You may want to consider adding some luminance or Ha
                  or
                  > > even just more Red frames as luminance to smooth out the image a
                  > bit.
                  > >
                  > > The red halos can be caused by a slight focus difference between
                  > red and other filters. Do you refocus between filters? At small F/
                  > > ratios, my Astronomik filters also exhibit the need to refocus.
                  > >
                  > > The blue halos are most likely due to some filter reflections off
                  > of the bright stars.
                  > >
                  > > There are some tricks in Photoshop using the minimum filter
                  and/or
                  > > star selection that let you reduce the effect. I'm not sure if
                  > these are available in ImagesPlus.
                  > >
                  > > Regards,
                  > >
                  > > -Paul
                  > >
                  > >
                  > > --- In ccd-newastro@yahoogroups.com, "Dennis Persyk"
                  > <dpersyk@a...>
                  > > wrote:
                  > > > I imaged IC5146, the Cocoon Nebula for 72 minutes. The image
                  > is an RGB of 24 minutes per component, each component a sum of 4-
                  > minute unguided frames. Takahashi E160 f/3.3 astrograph,
                  > AP1200GTO, MX716 and True Technology filters.
                  > > >
                  > > > Image at
                  > > > http://home.att.net/~dpersyk/new.htm
                  > > >
                  > > > Questions:
                  > > > 1) What causes the red halos around stars?
                  > > > 2) Is there a way to mitigate them in processing?
                  > > >
                  > > > Thanks for the help.
                  > > >
                  > > > Clear skies,
                  > > >
                  > > > Dennis Persyk
                  > > > Igloo Observatory Home Page http://dpersyk.home.att.net
                  > > > Hampshire, IL
                • Dennis Persyk
                  Hi Paul, That s great! Thanks. I especially like the select stars procedure. I assume the 8-bit restriction does not apply to CS. Now I need to practice,
                  Message 8 of 18 , Sep 19, 2004
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                    Hi Paul,

                    That's great! Thanks. I especially like the select stars
                    procedure. I assume the 8-bit restriction does not apply to CS.
                    Now I need to practice, practice, practice.

                    Clear skies,

                    Dennis

                    --- In ccd-newastro@yahoogroups.com, "Paul K" <paul@p...> wrote:
                    > Hi Dennis,
                    >
                    > Already did :-) Here are the two articles that should get you
                    started:
                    >
                    > http://pk.darkhorizons.org/PSStarBloat.htm
                    > http://pk.darkhorizons.org/stars.htm
                    >
                    > The first one will helps reduce the star size. In your case,
                    you'll probably want to apply it selectively, just to the red
                    channel.
                    >
                    > The second article shows how to select just the stars, leaving the
                    > nebulosity untouched. Once you do this, you could use the minimum
                    > filter, as in the first article, try an Unsharp mask to reduce
                    star size, or even just reduce red color saturation.
                    >
                    > Another possibility is to select the difference between the stars
                    in red channel, and say, the green. Then, you could simply reduce
                    the red color saturation, making the red flares into a more neutral
                    > color, or use curves/levels to make the red flares less bright.
                    >
                    > Regards,
                    >
                    > -Paul
                    >
                    > --- In ccd-newastro@yahoogroups.com, "Dennis Persyk"
                    <dpersyk@a...>
                    > wrote:
                    > > Hi Paul,
                    > >
                    > > Thanks for the feedback. I am starting to take luminance frames
                    > now and they help a lot.
                    > >
                    > > I do refocus frequently as the E160 has a large d(focus)/d(temp)
                    > > derivative. A carbon tube would probably benefit this scope
                    > > considerably.
                    > >
                    > > I also have PS CS but don't know how to use it! If you could
                    post a checklist for your technique in PS I'd like to give it a try.
                    > >
                    > > Clear skies,
                    > >
                    > > Dennis
                    > >
                    > > --- In ccd-newastro@yahoogroups.com, "Paul K" <paul@p...> wrote:
                    > > > Hi Dennis,
                    > > >
                    > > > Nice shot! You may want to consider adding some luminance or
                    Ha or
                    > > > even just more Red frames as luminance to smooth out the image
                    a bit.
                    > > >
                    > > > The red halos can be caused by a slight focus difference
                    between red and other filters. Do you refocus between filters? At
                    small F/ ratios, my Astronomik filters also exhibit the need to
                    refocus.
                    > > >
                    > > > The blue halos are most likely due to some filter reflections
                    off of the bright stars.
                    > > >
                    > > > There are some tricks in Photoshop using the minimum filter
                    > and/or star selection that let you reduce the effect. I'm not
                    sure if these are available in ImagesPlus.
                    > > >
                    > > > Regards,
                    > > >
                    > > > -Paul
                    > > >
                    > > >
                    > > > --- In ccd-newastro@yahoogroups.com, "Dennis Persyk"
                    > > <dpersyk@a...>
                    > > > wrote:
                    > > > > I imaged IC5146, the Cocoon Nebula for 72 minutes. The
                    image is an RGB of 24 minutes per component, each component a sum
                    of 4- minute unguided frames. Takahashi E160 f/3.3 astrograph,
                    > > AP1200GTO, MX716 and True Technology filters.
                    > > > >
                    > > > > Image at
                    > > > > http://home.att.net/~dpersyk/new.htm
                    > > > >
                    > > > > Questions:
                    > > > > 1) What causes the red halos around stars?
                    > > > > 2) Is there a way to mitigate them in processing?
                    > > > >
                    > > > > Thanks for the help.
                    > > > >
                    > > > > Clear skies,
                    > > > >
                    > > > > Dennis Persyk
                    > > > > Igloo Observatory Home Page http://dpersyk.home.att.net
                    > > > > Hampshire, IL
                  • Paul K
                    Yep! No need to convert to 8-bit in CS. The original article was written for PS 6.0 where that was a requirement :) Regards, -Paul ... the ... neutral
                    Message 9 of 18 , Sep 19, 2004
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                      Yep! No need to convert to 8-bit in CS. The original article was
                      written for PS 6.0 where that was a requirement :)

                      Regards,

                      -Paul

                      --- In ccd-newastro@yahoogroups.com, "Dennis Persyk" <dpersyk@a...>
                      wrote:
                      > Hi Paul,
                      >
                      > That's great! Thanks. I especially like the select stars
                      > procedure. I assume the 8-bit restriction does not apply to CS.
                      > Now I need to practice, practice, practice.
                      >
                      > Clear skies,
                      >
                      > Dennis
                      >
                      > --- In ccd-newastro@yahoogroups.com, "Paul K" <paul@p...> wrote:
                      > > Hi Dennis,
                      > >
                      > > Already did :-) Here are the two articles that should get you
                      > started:
                      > >
                      > > http://pk.darkhorizons.org/PSStarBloat.htm
                      > > http://pk.darkhorizons.org/stars.htm
                      > >
                      > > The first one will helps reduce the star size. In your case,
                      > you'll probably want to apply it selectively, just to the red
                      > channel.
                      > >
                      > > The second article shows how to select just the stars, leaving
                      the
                      > > nebulosity untouched. Once you do this, you could use the minimum
                      > > filter, as in the first article, try an Unsharp mask to reduce
                      > star size, or even just reduce red color saturation.
                      > >
                      > > Another possibility is to select the difference between the stars
                      > in red channel, and say, the green. Then, you could simply reduce
                      > the red color saturation, making the red flares into a more
                      neutral
                      > > color, or use curves/levels to make the red flares less bright.
                      > >
                      > > Regards,
                      > >
                      > > -Paul
                    • George Hall
                      Here is a monochrome version of the Cocoon Nebula. I have been attempting to produce a color version but my color data is too poor. I am using the Ted Agos
                      Message 10 of 18 , Sep 2, 2006
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                        Here is a monochrome version of the Cocoon Nebula. I have been
                        attempting to produce a color version but my color data is too poor. I
                        am using the Ted Agos Focal Reducer which causes very bad vinietting
                        with my system. I will have to try for more color data when the weather
                        permits. This is the first image that I have processed with CCDStack. I
                        like the software. It will take me quite a while to be able to fully
                        utilize its capabilities.
                        http://homepage.mac.com/joanlvh/Astronomy/CocoonNebula.html
                        George

                        --
                        George Hall
                        12" LX200GPS ST-8XME, AO-7
                        Supercharge # 3777-2012
                        Dallas, Texas USA
                        george2003 "at" sbcglobal.net
                        http://homepage.mac.com/joanlvh/Astronomy
                      • Steve Reilly
                        Hello George, There s plenty of data but maybe you used the wrong darks, as there are many black specks in the final image. Looks good though. Steve ... From:
                        Message 11 of 18 , Sep 2, 2006
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                          Hello George,

                          There's plenty of data but maybe you used the wrong darks, as there are many
                          black specks in the final image. Looks good though.

                          Steve

                          -----Original Message-----
                          From: ccd-newastro@yahoogroups.com [mailto:ccd-newastro@yahoogroups.com] On
                          Behalf Of George Hall
                          Sent: Saturday, September 02, 2006 7:02 PM
                          To: ccd-newastro@yahoogroups.com
                          Subject: [ccd-newastro] Cocoon Nebula

                          Here is a monochrome version of the Cocoon Nebula. I have been
                          attempting to produce a color version but my color data is too poor. I
                          am using the Ted Agos Focal Reducer which causes very bad vinietting
                          with my system. I will have to try for more color data when the weather
                          permits. This is the first image that I have processed with CCDStack. I
                          like the software. It will take me quite a while to be able to fully
                          utilize its capabilities.
                          http://homepage.mac.com/joanlvh/Astronomy/CocoonNebula.html
                          George

                          --
                          George Hall
                          12" LX200GPS ST-8XME, AO-7
                          Supercharge # 3777-2012
                          Dallas, Texas USA
                          george2003 "at" sbcglobal.net
                          http://homepage.mac.com/joanlvh/Astronomy





                          Yahoo! Groups Links
                        • George Hall
                          Steve, Thanks for the feed-back. I have checked the darks, I think they are the correct ones. I may re-shoot the darks as they are several months old. I
                          Message 12 of 18 , Sep 4, 2006
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                            Steve,

                            Thanks for the feed-back. I have checked the darks, I think they are the
                            correct ones. I may re-shoot the darks as they are several months old. I
                            reprocessed the image with more agressive bad data rejection in
                            CCDStack. Here is the most recent version.
                            http://homepage.mac.com/joanlvh/Astronomy/CocoonNebula.html

                            George

                            Steve Reilly wrote:

                            > Hello George,
                            >
                            > There's plenty of data but maybe you used the wrong darks, as there
                            > are many
                            > black specks in the final image. Looks good though.
                            >
                            > Steve
                            >
                            > -----Original Message-----
                            > From: ccd-newastro@yahoogroups.com
                            > <mailto:ccd-newastro%40yahoogroups.com>
                            > [mailto:ccd-newastro@yahoogroups.com
                            > <mailto:ccd-newastro%40yahoogroups.com>] On
                            > Behalf Of George Hall
                            > Sent: Saturday, September 02, 2006 7:02 PM
                            > To: ccd-newastro@yahoogroups.com <mailto:ccd-newastro%40yahoogroups.com>
                            > Subject: [ccd-newastro] Cocoon Nebula
                            >
                            > Here is a monochrome version of the Cocoon Nebula. I have been
                            > attempting to produce a color version but my color data is too poor. I
                            > am using the Ted Agos Focal Reducer which causes very bad vinietting
                            > with my system. I will have to try for more color data when the weather
                            > permits. This is the first image that I have processed with CCDStack. I
                            > like the software. It will take me quite a while to be able to fully
                            > utilize its capabilities.
                            > http://homepage.mac.com/joanlvh/Astronomy/CocoonNebula.html
                            > <http://homepage.mac.com/joanlvh/Astronomy/CocoonNebula.html>
                            > George
                            >
                            > --
                            > George Hall
                            > 12" LX200GPS ST-8XME, AO-7
                            > Supercharge # 3777-2012
                            > Dallas, Texas USA
                            > george2003 "at" sbcglobal.net
                            > http://homepage.mac.com/joanlvh/Astronomy
                            > <http://homepage.mac.com/joanlvh/Astronomy>
                            >
                            > Yahoo! Groups Links
                            >
                            >



                            --
                            George Hall
                            12" LX200GPS ST-8XME, AO-7
                            Supercharge # 3777-2012
                            Dallas, Texas USA
                            george2003 "at" sbcglobal.net
                            http://homepage.mac.com/joanlvh/Astronomy
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