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M31 mosaic with 4" TMB and the Canon 10D

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  • Johannes Schedler
    I like to share a 2-part mosaic done during some September nights. The assembling and processing caused quite a lot of work to bring out the distortion at the
    Message 1 of 28 , Oct 1, 2003
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      I like to share a 2-part mosaic done during some September nights.

      The assembling and processing caused quite a lot of work to bring out
      the distortion at the edges and the brightness differences, but the
      result is quite ok, see:
      http://panther-observatory.com/deepsky.htm#87

      As flattener I used the Televue 0.8x type for the pronto, some
      distortion still was left at the corners.

      Johannes
    • W. Gondella
      ... From: Johannes Schedler To: Sent: Wednesday, October 01, 2003 3:14 AM Subject: [tmboptical] M31 mosaic
      Message 2 of 28 , Oct 1, 2003
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        ----- Original Message -----
        From: "Johannes Schedler" <sche2005@...>
        To: <tmboptical@yahoogroups.com>
        Sent: Wednesday, October 01, 2003 3:14 AM
        Subject: [tmboptical] M31 mosaic with 4" TMB and the Canon 10D


        > I like to share a 2-part mosaic done during some September nights.
        >
        > The assembling and processing caused quite a lot of work to bring out
        > the distortion at the edges and the brightness differences, but the
        > result is quite ok, see:
        > http://panther-observatory.com/deepsky.htm#87
        >
        > As flattener I used the Televue 0.8x type for the pronto, some
        > distortion still was left at the corners.
        >
        > Johannes



        Johannes,

        Superb, delightful work, right up there with the best images I've ever seen of Andromeda.

        Quite ok, indeed.

        WG
      • Mike Unsold
        Hi Johannes, Your M31 image is so outstanding that it has already been the talk of the TMB list. Scroll back through the list a page or two. Well Done! Mike
        Message 3 of 28 , Oct 1, 2003
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          Hi Johannes,

          Your M31 image is so outstanding that it has already been the talk of
          the TMB list. Scroll back through the list a page or two.

          Well Done!
          Mike

          >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
          I like to share a 2-part mosaic done during some September nights.

          The assembling and processing caused quite a lot of work to bring out
          the distortion at the edges and the brightness differences, but the
          result is quite ok, see:
          http://panther-observatory.com/deepsky.htm#87

          As flattener I used the Televue 0.8x type for the pronto, some
          distortion still was left at the corners.

          Johannes
        • digidodi
          I know what you are talking about... Mine with the TMB80mm was a nightmare to get it assembled and colorbalanced right. I used 3 frames with CCD in France, and
          Message 4 of 28 , Oct 3, 2003
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            I know what you are talking about... Mine with the TMB80mm was a
            nightmare to get it assembled and colorbalanced right. I used 3
            frames with CCD in France, and next one CCD color shot with Nikon
            lens and RGB filters from the center of Ghent. It's nice to compare
            though! Don't know if you have seen it, but here it is again:

            http://users.pandora.be/create/hotzone/galaxies/m31.htm

            D.

            --- In tmboptical@yahoogroups.com, "Johannes Schedler"
            <sche2005@y...> wrote:
            > I like to share a 2-part mosaic done during some September nights.
            >
            > The assembling and processing caused quite a lot of work to bring
            out
            > the distortion at the edges and the brightness differences, but the
            > result is quite ok, see:
            > http://panther-observatory.com/deepsky.htm#87
            >
            > As flattener I used the Televue 0.8x type for the pronto, some
            > distortion still was left at the corners.
            >
            > Johannes
          • Johannes Schedler
            Very nice, Dominique, have not seen your M31 before! The new Veil mosaic was even worse, I had to stitch together 4 frames... Johannes
            Message 5 of 28 , Oct 3, 2003
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              Very nice, Dominique, have not seen your M31 before!

              The new Veil mosaic was even worse, I had to stitch together 4
              frames...

              Johannes
              http://panther-observatory.com

              --- In tmboptical@yahoogroups.com, "digidodi" <ddierick@h...> wrote:
              > I know what you are talking about... Mine with the TMB80mm was a
              > nightmare to get it assembled and colorbalanced right. I used 3
              > frames with CCD in France, and next one CCD color shot with Nikon
              > lens and RGB filters from the center of Ghent. It's nice to compare
              > though! Don't know if you have seen it, but here it is again:
              >
              > http://users.pandora.be/create/hotzone/galaxies/m31.htm
              >
              > D.
              >
              > --- In tmboptical@yahoogroups.com, "Johannes Schedler"
              > <sche2005@y...> wrote:
              > > I like to share a 2-part mosaic done during some September nights.
              > >
              > > The assembling and processing caused quite a lot of work to bring
              > out
              > > the distortion at the edges and the brightness differences, but
              the
              > > result is quite ok, see:
              > > http://panther-observatory.com/deepsky.htm#87
              > >
              > > As flattener I used the Televue 0.8x type for the pronto, some
              > > distortion still was left at the corners.
              > >
              > > Johannes
            • Michael Downing
              Hi everyone, I shot this image last night of the M33 (Pinwheel Galaxy) with the TMB-180 on the Paramount Me with an ST-10XE. http://www.astroden.com/180_90.jpg
              Message 6 of 28 , Oct 3, 2003
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                Hi everyone,
                I shot this image last night of the M33 (Pinwheel Galaxy) with the
                TMB-180 on the Paramount Me with an ST-10XE.
                http://www.astroden.com/180_90.jpg

                LRGB=30:30:30:30, Dark Subtract, DDP.
                http://www.astroden.com/st10/tmb180/pinwheel_galaxy.jpg

                Michael Downing
                www.astroden.com <http://www.astroden.com/>




                [Non-text portions of this message have been removed]
              • Mike C
                Looks nice. Got some structure appearing in that nebula... in another galaxy!
                Message 7 of 28 , Oct 3, 2003
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                  Looks nice. Got some structure appearing in that nebula... in another galaxy!

                  > LRGB=30:30:30:30, Dark Subtract, DDP.
                  > http://www.astroden.com/st10/tmb180/pinwheel_galaxy.jpg
                • bwakel
                  Mike Nice image, did you have to bring out the colour in processing or was most of it there due to the relatively long exposure? I just posted my own shot
                  Message 8 of 28 , Oct 3, 2003
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                    Mike

                    Nice image, did you have to bring out the colour in processing or
                    was most of it there due to the relatively long exposure? I just
                    posted my own shot here:

                    http://website.lineone.net/~liz.wakelin/page17.html

                    using my APM/TMB 130 f/7 on its highly stressed Losmandy GM8 using
                    my Fuji S2 Pro, manually guided, and I don't get the colour that
                    you've managed to bring out so nicely.

                    Barry

                    --- In tmboptical@yahoogroups.com, "Michael Downing" <michael@s...>
                    wrote:
                    > Hi everyone,
                    > I shot this image last night of the M33 (Pinwheel Galaxy) with the
                    > TMB-180 on the Paramount Me with an ST-10XE.
                    > http://www.astroden.com/180_90.jpg
                    >
                    > LRGB=30:30:30:30, Dark Subtract, DDP.
                    > http://www.astroden.com/st10/tmb180/pinwheel_galaxy.jpg
                    >
                    > Michael Downing
                    > www.astroden.com <http://www.astroden.com/>
                    >
                    >
                    >
                    >
                    > [Non-text portions of this message have been removed]
                  • Michael Downing
                    Hi Barry, Thanks for the thumbs up. I only adjusted the RGB levels individually to enhance the color. I am not sure what a Fuji S2 is, could you fill me in on
                    Message 9 of 28 , Oct 3, 2003
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                      Hi Barry,
                      Thanks for the thumbs up.
                      I only adjusted the RGB levels individually to enhance the color.
                      I am not sure what a Fuji S2 is, could you fill me in on that?

                      Michael Downing
                      www.astroden.com <http://www.astroden.com/>



                      -----Original Message-----
                      From: bwakel [mailto:bwakelin@...]
                      Sent: Friday, October 03, 2003 5:08 PM
                      To: tmboptical@yahoogroups.com
                      Subject: [tmboptical] Re: Pinwheel Galaxy

                      Mike

                      Nice image, did you have to bring out the colour in processing or
                      was most of it there due to the relatively long exposure? I just
                      posted my own shot here:

                      http://website.lineone.net/~liz.wakelin/page17.html

                      using my APM/TMB 130 f/7 on its highly stressed Losmandy GM8 using
                      my Fuji S2 Pro, manually guided, and I don't get the colour that
                      you've managed to bring out so nicely.

                      Barry

                      --- In tmboptical@yahoogroups.com, "Michael Downing" <michael@s...>
                      wrote:
                      > Hi everyone,
                      > I shot this image last night of the M33 (Pinwheel Galaxy) with the
                      > TMB-180 on the Paramount Me with an ST-10XE.
                      > http://www.astroden.com/180_90.jpg
                      >
                      > LRGB=30:30:30:30, Dark Subtract, DDP.
                      > http://www.astroden.com/st10/tmb180/pinwheel_galaxy.jpg
                      >
                      > Michael Downing
                      > www.astroden.com <http://www.astroden.com/>
                      >
                      >
                      >
                      >
                      > [Non-text portions of this message have been removed]





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                    • bwakel
                      Michael Thanks for the info, I ll try fiddling with my RGB levels. The Fuji S2 Pro is their top-of-the-line digital SLR, it competes more or less directly with
                      Message 10 of 28 , Oct 4, 2003
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                        Michael

                        Thanks for the info, I'll try fiddling with my RGB levels.

                        The Fuji S2 Pro is their top-of-the-line digital SLR, it competes
                        more or less directly with the Canon 10D. See here for a full
                        review:

                        http://www.dpreview.com/reviews/fujis2pro/

                        --- In tmboptical@yahoogroups.com, "Michael Downing" <michael@s...>
                        wrote:
                        > Hi Barry,
                        > Thanks for the thumbs up.
                        > I only adjusted the RGB levels individually to enhance the color.
                        > I am not sure what a Fuji S2 is, could you fill me in on that?
                        >
                        > Michael Downing
                        > www.astroden.com <http://www.astroden.com/>
                        >
                        >
                        >
                        > -----Original Message-----
                        > From: bwakel [mailto:bwakelin@p...]
                        > Sent: Friday, October 03, 2003 5:08 PM
                        > To: tmboptical@yahoogroups.com
                        > Subject: [tmboptical] Re: Pinwheel Galaxy
                        >
                        > Mike
                        >
                        > Nice image, did you have to bring out the colour in processing or
                        > was most of it there due to the relatively long exposure? I just
                        > posted my own shot here:
                        >
                        > http://website.lineone.net/~liz.wakelin/page17.html
                        >
                        > using my APM/TMB 130 f/7 on its highly stressed Losmandy GM8 using
                        > my Fuji S2 Pro, manually guided, and I don't get the colour that
                        > you've managed to bring out so nicely.
                        >
                        > Barry
                        >
                        > --- In tmboptical@yahoogroups.com, "Michael Downing"
                        <michael@s...>
                        > wrote:
                        > > Hi everyone,
                        > > I shot this image last night of the M33 (Pinwheel Galaxy) with
                        the
                        > > TMB-180 on the Paramount Me with an ST-10XE.
                        > > http://www.astroden.com/180_90.jpg
                        > >
                        > > LRGB=30:30:30:30, Dark Subtract, DDP.
                        > > http://www.astroden.com/st10/tmb180/pinwheel_galaxy.jpg
                        > >
                        > > Michael Downing
                        > > www.astroden.com <http://www.astroden.com/>
                        > >
                        > >
                        > >
                        > >
                        > > [Non-text portions of this message have been removed]
                        >
                        >
                        >
                        >
                        >
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                      • Michael Downing
                        Ok here is a second try of the M33 image with less blue and a little more contrast. LRGB=30:30:30:30, Dark Subtract, DDP.
                        Message 11 of 28 , Oct 4, 2003
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                          Ok here is a second try of the M33 image with less blue and a little
                          more contrast.

                          LRGB=30:30:30:30, Dark Subtract, DDP.
                          <http://www.astroden.com/st10/tmb180/pinwheel_galaxy.jpg>
                          http://www.astroden.com/st10/tmb180/pinwheel_galaxy.jpg

                          Michael Downing
                          <http://www.astroden.com/> http://www.astroden.com/





                          [Non-text portions of this message have been removed]
                        • Richard Chalfan
                          There was a thread last week where I posted some comments about color correcting lenses, particularly achromats. There IS another way to make an achromat
                          Message 12 of 28 , Oct 6, 2003
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                            There was a thread last week where I posted some
                            comments about color correcting lenses, particularly
                            achromats.

                            There IS another way to make an achromat (using cheap
                            "normal" glass) with the VISUAL APPEARANCE of less
                            color error. I simply was not thinking in these terms
                            when I made my post. So I will add the "other method"
                            now.

                            Generally, when color correction of a doublet is being
                            discussed, the discussion assumes what is known as C-F
                            correction. In C-F correction, the lens is designed
                            to bring yellow-green light (555 nm wavelength) to the
                            shortest focal length; and the focal lengths of the
                            blue "F" line (463 nm) and the red "C" line (656 nm)
                            are made coincident. My post made, but didn't state,
                            this assumption. I also discussed semi-apo and apo
                            correction where I assumed the secondary spectrum was
                            measured against the focus plane where the C and F
                            rays were coincident.

                            If you want to maximize the amount of useful light
                            brought to focus in the human eye, this is a good
                            choice. Under "photopic" illumination (that is,
                            bright enough to see color), the eye is roughly
                            equally sensitive to the C and F colors, and most
                            sensitive to the 555 nm yellow-green.

                            But you can get the appearance of better color
                            correction (especially on a bright object) by
                            correcting for red and green (C-e correction), with
                            peak sensitivity in the yellow. This sacrifices
                            correction in the blue and violet, but throws them
                            further out of focus so that you don't perceive the
                            purple color fringing very much. This with the same
                            normal achromat glass types.

                            A bright image helps, because it causes the iris to
                            stop down, which can effectively operate the entire
                            system at a long f-stop. Binoculars are a good
                            example of what happens with a bright image. A
                            typical 7x50 binocular objective is a "normal" glass
                            achromat working at f/4. You might think that daytime
                            images would be horrible. But look what happens. The
                            exit pupil of our 7x50 is 7.1". During daylight, the
                            typical person's pupil is 2mm or less! If you assume
                            your iris shuts down to 2mm, then you are only using
                            2/7.1 of the objective diameter. So you are USING the
                            50mm f/4 objective at f/(4 x (2/7.1)) or a bit over
                            f/14! A 50mm f/14 lens doesn't have bad color error!
                            So the inexpensive binocular produces a pretty good
                            daytime image. (And at night you can't see the color
                            error with dim objects so they seem to work pretty
                            well there too)!

                            The same principal would hold with a fast achromat
                            telescope objective used at low power. And if you
                            correct for red-green rather than red-blue, it would
                            produce noticeably more color free views on a bright
                            object like the moon.

                            Now I have no idea which (if any) achromat
                            manufacturers currently use C-e correction to produce
                            a "better" achromat. Maybe none, maybe all of them
                            use something a little different than C-F. But it IS
                            a way to get less apparent color fringing (under some
                            conditions) at no extra cost. Of course you DO give
                            things up too. Because your eye sees less total
                            light, a C-e lens would not show as dim stars as a C-F
                            lens. And a white object at focus would appear
                            yellower in the C-e lens than in a C-F lens.

                            Richard

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                          • tmboptical
                            ... Hi Richard, That is quite right. Some of the Zeiss achromats, and Clark objectives were color corrected this way. There is also another end result --
                            Message 13 of 28 , Oct 6, 2003
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                              --- In tmboptical@yahoogroups.com, Richard Chalfan <rchalfan@y...>
                              wrote:
                              >
                              > But you can get the appearance of better color
                              > correction (especially on a bright object) by
                              > correcting for red and green (C-e correction), with
                              > peak sensitivity in the yellow. This sacrifices
                              > correction in the blue and violet, but throws them
                              > further out of focus so that you don't perceive the
                              > purple color fringing very much. This with the same
                              > normal achromat glass types.

                              Hi Richard,

                              That is quite right. Some of the Zeiss achromats, and
                              Clark objectives were color corrected this way. There
                              is also another end result -- better correction for the
                              planet Mars. Because Mars was the object of the greatest
                              interest to the early visual planetary observers,
                              pushing the color correction closer to the red end of
                              the spectrum, improved visual definition on Mars. But
                              as you say, with poorer (larger) blue/violet spot sizes.
                              Because these were very large achromats, the blue/violet
                              halo was so large already, it would not have made much,
                              if any difference visually in the blue end, if the lens
                              was corrected for C-e-F.

                              > Now I have no idea which (if any) achromat
                              > manufacturers currently use C-e correction to produce
                              > a "better" achromat. Maybe none, maybe all of them
                              > use something a little different than C-F. But it IS
                              > a way to get less apparent color fringing (under some
                              > conditions) at no extra cost. Of course you DO give
                              > things up too. Because your eye sees less total
                              > light, a C-e lens would not show as dim stars as a C-F
                              > lens. And a white object at focus would appear
                              > yellower in the C-e lens than in a C-F lens.
                              >
                              > Richard

                              I can't answer that question either, but the TMB
                              achromats were corrected for the C and F lines at the
                              70.7% zone, with the peak correction at 555nm. For a
                              reasonable sized achromat, this is the correct way to
                              design an achromat (Richard Buchroeder said that my
                              apochromats and achromats are the best designed of any
                              on the market), unless the telescope is going to be
                              used only as a deep sky instrument, and in that case,
                              peak correction should be at 510nm (Scotopic eye).

                              Thomas Back
                            • Richard Chalfan
                              ... I didn t know that. I have read that some early (pre-1900) photographic objectives had very unusual color correction by our standards today. Since the
                              Message 14 of 28 , Oct 6, 2003
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                                --- tmboptical <TMBoptical@...> wrote:
                                > Hi Richard,
                                >
                                > That is quite right. Some of the Zeiss achromats,
                                > and
                                > Clark objectives were color corrected this way.

                                I didn't know that.

                                I have read that some early (pre-1900) photographic
                                objectives had very unusual color correction by our
                                standards today. Since the eye's peak sensitivity is
                                in the yellow-green, and early (ordinary or
                                orthochromatic) photographic emulsions were sensitive
                                only toward the blue end of the spectrum, some lenses
                                were green-blue corrected.

                                > There
                                > is also another end result -- better correction for
                                > the
                                > planet Mars. Because Mars was the object of the
                                > greatest
                                > interest to the early visual planetary observers,
                                > pushing the color correction closer to the red end
                                > of
                                > the spectrum, improved visual definition on Mars.
                                > But
                                > as you say, with poorer (larger) blue/violet spot
                                > sizes.
                                > Because these were very large achromats, the
                                > blue/violet
                                > halo was so large already, it would not have made
                                > much,
                                > if any difference visually in the blue end, if the
                                > lens
                                > was corrected for C-e-F.

                                That makes sense.

                                > > Now I have no idea which (if any) achromat
                                > > manufacturers currently use C-e correction to
                                > > produce
                                > > a "better" achromat.

                                > I can't answer that question either, but the TMB
                                > achromats were corrected for the C and F lines at
                                > the
                                > 70.7% zone, with the peak correction at 555nm. For a
                                > reasonable sized achromat, this is the correct way
                                > to
                                > design an achromat (Richard Buchroeder said that my
                                > apochromats and achromats are the best designed of
                                > any
                                > on the market),

                                High praise indeed!

                                > unless the telescope is going to be
                                > used only as a deep sky instrument, and in that
                                > case,
                                > peak correction should be at 510nm (Scotopic eye).

                                Do you know if anyone makes these? I have wondered if
                                any spotting scopes or binoculars have scotopic
                                correction. It might give a noticeable daytime
                                performance edge over scopes with "standard" achromat
                                correction.

                                Of course if the scope were an apo I don't know if you
                                could see the difference between a scotopic or
                                photopic optimized objective.
                                >
                                > Thomas Back
                                >
                                >
                                Richard

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                              • wjburg
                                Richard, With due respect I hope you realize you are talking with one of the choir masters.
                                Message 15 of 28 , Oct 6, 2003
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                                  Richard,

                                  With due respect I hope you realize you are talking with one of the
                                  choir masters.

                                  --- In tmboptical@yahoogroups.com, Richard Chalfan <rchalfan@y...>
                                  wrote:
                                  >
                                  > --- tmboptical <TMBoptical@a...> wrote:
                                  > > Hi Richard,
                                  > >
                                  > > That is quite right. Some of the Zeiss achromats,
                                  > > and
                                  > > Clark objectives were color corrected this way.
                                  >
                                  > I didn't know that.
                                  >
                                  > I have read that some early (pre-1900) photographic
                                  > objectives had very unusual color correction by our
                                  > standards today. Since the eye's peak sensitivity is
                                  > in the yellow-green, and early (ordinary or
                                  > orthochromatic) photographic emulsions were sensitive
                                  > only toward the blue end of the spectrum, some lenses
                                  > were green-blue corrected.
                                  >
                                  > > There
                                  > > is also another end result -- better correction for
                                  > > the
                                  > > planet Mars. Because Mars was the object of the
                                  > > greatest
                                  > > interest to the early visual planetary observers,
                                  > > pushing the color correction closer to the red end
                                  > > of
                                  > > the spectrum, improved visual definition on Mars.
                                  > > But
                                  > > as you say, with poorer (larger) blue/violet spot
                                  > > sizes.
                                  > > Because these were very large achromats, the
                                  > > blue/violet
                                  > > halo was so large already, it would not have made
                                  > > much,
                                  > > if any difference visually in the blue end, if the
                                  > > lens
                                  > > was corrected for C-e-F.
                                  >
                                  > That makes sense.
                                  >
                                  > > > Now I have no idea which (if any) achromat
                                  > > > manufacturers currently use C-e correction to
                                  > > > produce
                                  > > > a "better" achromat.
                                  >
                                  > > I can't answer that question either, but the TMB
                                  > > achromats were corrected for the C and F lines at
                                  > > the
                                  > > 70.7% zone, with the peak correction at 555nm. For a
                                  > > reasonable sized achromat, this is the correct way
                                  > > to
                                  > > design an achromat (Richard Buchroeder said that my
                                  > > apochromats and achromats are the best designed of
                                  > > any
                                  > > on the market),
                                  >
                                  > High praise indeed!
                                  >
                                  > > unless the telescope is going to be
                                  > > used only as a deep sky instrument, and in that
                                  > > case,
                                  > > peak correction should be at 510nm (Scotopic eye).
                                  >
                                  > Do you know if anyone makes these? I have wondered if
                                  > any spotting scopes or binoculars have scotopic
                                  > correction. It might give a noticeable daytime
                                  > performance edge over scopes with "standard" achromat
                                  > correction.
                                  >
                                  > Of course if the scope were an apo I don't know if you
                                  > could see the difference between a scotopic or
                                  > photopic optimized objective.
                                  > >
                                  > > Thomas Back
                                  > >
                                  > >
                                  > Richard
                                  >
                                  > __________________________________
                                  > Do you Yahoo!?
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                                • Richard Chalfan
                                  Indeed I do, and were Tom not so busy he might well have gotten involved when the thread started and I might not have posted at all! There have been several
                                  Message 16 of 28 , Oct 6, 2003
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                                    Indeed I do, and were Tom not so busy he might well
                                    have gotten involved when the thread started and I
                                    might not have posted at all!

                                    There have been several threads during Tom's recent
                                    "busy" (OK; frenetic, hectic, impossibly overworked)
                                    period where one or another of us delved into
                                    technical topics or answered questions where Tom might
                                    otherwise have led the discussion. But he simply
                                    hasn't had the time to get involved.

                                    I don't feel anyone has tried to upstage Tom though, I
                                    know I can't.

                                    R

                                    --- wjburg <wjburg@...> wrote:
                                    > Richard,
                                    >
                                    > With due respect I hope you realize you are talking
                                    > with one of the
                                    > choir masters.


                                    __________________________________
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                                  • W. Gondella
                                    I think (know) Richard only intends, in the best way, to make meaningful contributions here. And he does every time. Richard certainly knows what he is
                                    Message 17 of 28 , Oct 6, 2003
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                                      I think (know) Richard only intends, in the best way, to make meaningful contributions
                                      here. And he does every time. Richard certainly knows what he is talking about, and
                                      offers his thoughts generously, and with no thought of trying to appear as the "resident
                                      expert", compete with, or to try to upstage Tom.

                                      I don't know why anyone would, or might, think that, anyway.

                                      What little time Tom has had to share with us has been entirely in support and agreement
                                      with Richard's comments and deductions, so Richard must be generally on the "straight and
                                      narrow," and I feel glad Richard is willing to contribute his thoughts when others,
                                      especially Tom, might otherwise be too distracted with demanding work to do so himself as
                                      often as he might like.

                                      WayneG


                                      ----- Original Message -----
                                      From: "Richard Chalfan" <rchalfan@...>
                                      To: <tmboptical@yahoogroups.com>
                                      Sent: Monday, October 06, 2003 6:08 PM
                                      Subject: Re: [tmboptical] Re: Color Correction


                                      > Indeed I do, and were Tom not so busy he might well
                                      > have gotten involved when the thread started and I
                                      > might not have posted at all!
                                      >
                                      > There have been several threads during Tom's recent
                                      > "busy" (OK; frenetic, hectic, impossibly overworked)
                                      > period where one or another of us delved into
                                      > technical topics or answered questions where Tom might
                                      > otherwise have led the discussion. But he simply
                                      > hasn't had the time to get involved.
                                      >
                                      > I don't feel anyone has tried to upstage Tom though, I
                                      > know I can't.
                                      >
                                      > R
                                      >
                                      > --- wjburg <wjburg@...> wrote:
                                      > > Richard,
                                      > >
                                      > > With due respect I hope you realize you are talking
                                      > > with one of the
                                      > > choir masters.
                                      >
                                      >
                                    • wjburg
                                      I appear to definitely have misread the intent of the inputs and offer my sincere apologiy. My thoughts were in the line of knowing what has been posted as
                                      Message 18 of 28 , Oct 6, 2003
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                                        I appear to definitely have misread the intent of the inputs and
                                        offer my sincere apologiy. My thoughts were in the line of knowing
                                        what has been posted as Thomas' objective in the fine products he has
                                        created. I suspect the type of speciality products mentioned are
                                        truly feasible, even more so than in the Clark's era, however would
                                        not be a truly income producing at a "mass" production level.

                                        IT would be nice if a shop were in a position to produce each unique
                                        idea at a reasonable price. Many a discovery has come from the
                                        courage to try something different.

                                        Respectfully submitted,
                                        bill

                                        --- In tmboptical@yahoogroups.com, "W. Gondella" <strehl985@c...>
                                        wrote:
                                        > I think (know) Richard only intends, in the best way, to make
                                        meaningful contributions
                                        > here. And he does every time. Richard certainly knows what he is
                                        talking about, and
                                        > offers his thoughts generously, and with no thought of trying to
                                        appear as the "resident
                                        > expert", compete with, or to try to upstage Tom.
                                        >
                                        > I don't know why anyone would, or might, think that, anyway.
                                        >
                                        > What little time Tom has had to share with us has been entirely in
                                        support and agreement
                                        > with Richard's comments and deductions, so Richard must be
                                        generally on the "straight and
                                        > narrow," and I feel glad Richard is willing to contribute his
                                        thoughts when others,
                                        > especially Tom, might otherwise be too distracted with demanding
                                        work to do so himself as
                                        > often as he might like.
                                        >
                                        > WayneG
                                        >
                                        >
                                        > ----- Original Message -----
                                        > From: "Richard Chalfan" <rchalfan@y...>
                                        > To: <tmboptical@yahoogroups.com>
                                        > Sent: Monday, October 06, 2003 6:08 PM
                                        > Subject: Re: [tmboptical] Re: Color Correction
                                        >
                                        >
                                        > > Indeed I do, and were Tom not so busy he might well
                                        > > have gotten involved when the thread started and I
                                        > > might not have posted at all!
                                        > >
                                        > > There have been several threads during Tom's recent
                                        > > "busy" (OK; frenetic, hectic, impossibly overworked)
                                        > > period where one or another of us delved into
                                        > > technical topics or answered questions where Tom might
                                        > > otherwise have led the discussion. But he simply
                                        > > hasn't had the time to get involved.
                                        > >
                                        > > I don't feel anyone has tried to upstage Tom though, I
                                        > > know I can't.
                                        > >
                                        > > R
                                        > >
                                        > > --- wjburg <wjburg@y...> wrote:
                                        > > > Richard,
                                        > > >
                                        > > > With due respect I hope you realize you are talking
                                        > > > with one of the
                                        > > > choir masters.
                                        > >
                                        > >
                                      • tmboptical
                                        ... Hi Richard, I wish I could spend more time with optical discussions, concepts, and little known reasons why telescopes optically perform the way they do.
                                        Message 19 of 28 , Oct 6, 2003
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                                          --- In tmboptical@yahoogroups.com, Richard Chalfan <rchalfan@y...>
                                          wrote:
                                          > Indeed I do, and were Tom not so busy he might well
                                          > have gotten involved when the thread started and I
                                          > might not have posted at all!
                                          >
                                          > There have been several threads during Tom's recent
                                          > "busy" (OK; frenetic, hectic, impossibly overworked)
                                          > period where one or another of us delved into
                                          > technical topics or answered questions where Tom might
                                          > otherwise have led the discussion. But he simply
                                          > hasn't had the time to get involved.
                                          >
                                          > I don't feel anyone has tried to upstage Tom though, I
                                          > know I can't.
                                          >
                                          > R

                                          Hi Richard,

                                          I wish I could spend more time with optical discussions,
                                          concepts, and little known reasons why telescopes optically
                                          perform the way they do. The fact is that I really don't
                                          have the time now. Hopefully, sometime in the future, I will
                                          have time to be more active on the TMB Optical Group.

                                          And please everyone, Richard is not upstaging me, he is
                                          one very knowledgeable optical person on our group, and I
                                          very much enjoy reading his posts.

                                          Thomas Back
                                        • Richard Chalfan
                                          Bill, ... No problem here! ... My ramblings about color correction actually had nothing to do with the thread about Tom s expanding his product line. I was
                                          Message 20 of 28 , Oct 7, 2003
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                                            Bill,

                                            --- wjburg <wjburg@...> wrote:
                                            > I appear to definitely have misread the intent of
                                            > the inputs and
                                            > offer my sincere apologiy.

                                            No problem here!

                                            > My thoughts were in the
                                            > line of knowing
                                            > what has been posted as Thomas' objective in the
                                            > fine products he has
                                            > created. I suspect the type of speciality products
                                            > mentioned are
                                            > truly feasible, even more so than in the Clark's
                                            > era, however would
                                            > not be a truly income producing at a "mass"
                                            > production level.

                                            My ramblings about color correction actually had
                                            nothing to do with the thread about Tom's expanding
                                            his product line. I was remiss for not making that
                                            clear. A week or so earlier there was a thread
                                            regarding color correction. I simply remembered that
                                            there is another way to (under some circumstances)
                                            give the eye a less colorful image, yet stay with
                                            normal glass. So I posted it for completeness.

                                            I apologize to anyone who may have found the post
                                            inappropriate, for any reason.

                                            Thanks!

                                            Richard

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                                          • Mark Hammons
                                            ... Richard, I actually found it very informative. I had no idea that one could reduce the violet halo of an achormat by making it LESS corrected at that
                                            Message 21 of 28 , Oct 7, 2003
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                                              >
                                              > My ramblings about color correction actually had
                                              > nothing to do with the thread about Tom's expanding
                                              > his product line. I was remiss for not making that
                                              > clear. A week or so earlier there was a thread
                                              > regarding color correction. I simply remembered that
                                              > there is another way to (under some circumstances)
                                              > give the eye a less colorful image, yet stay with
                                              > normal glass. So I posted it for completeness.
                                              >
                                              > I apologize to anyone who may have found the post
                                              > inappropriate, for any reason.
                                              >
                                              > Thanks!
                                              >
                                              > Richard
                                              >


                                              Richard,

                                              I actually found it very informative. I had no idea that one
                                              could reduce the violet halo of an achormat by making it
                                              LESS corrected at that wavelength but now that you
                                              explained it it makes perfect sense. I like learning more
                                              about optics and scopes like this.

                                              Mark
                                            • wjburg
                                              Richard and I have had a pleasant off line chat. In fact, his inputs have expanded my knowledge of optics in another direction even though I will never be a
                                              Message 22 of 28 , Oct 8, 2003
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                                                Richard and I have had a pleasant off line chat. In fact, his inputs
                                                have expanded my knowledge of optics in another direction even though
                                                I will never be a Thomas Back or Al Nagler.

                                                I hope Richard might work with Thomas in answering some of the
                                                questions that arise on this forum. Not every design request can be
                                                considered or put into production due to practical limitations of
                                                time and actual size of the market for a special use item.

                                                Thanks again, Richard for your sharing valuable information.

                                                bill
                                              • wjburg
                                                Richard, I was thinking, if someone really wanted to customize an instrument for use on one special object or situation, such as Mars, would it be worth while
                                                Message 23 of 28 , Oct 8, 2003
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                                                  Richard,

                                                  I was thinking, if someone really wanted to customize an instrument
                                                  for use on one special object or situation, such as Mars, would it be
                                                  worth while to go all the way and also tailor the eyepieces to that
                                                  application? Photographers often choose a film to compliment their
                                                  subject.

                                                  Best wishes,
                                                  bill

                                                  --- In tmboptical@yahoogroups.com, Richard Chalfan <rchalfan@y...>
                                                  wrote:
                                                  > There was a thread last week where I posted some
                                                  > comments about color correcting lenses, particularly
                                                  > achromats.
                                                  >
                                                  >
                                                • Richard Chalfan
                                                  Bill, ... I was thinking, if someone really wanted to customize an instrument for use on one special object or situation, such as Mars, would it be worth
                                                  Message 24 of 28 , Oct 9, 2003
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                                                    Bill,

                                                    --- wjburg <wjburg@...> wrote:
                                                    I was thinking, if someone really wanted to customize
                                                    an instrument for use on one special object or
                                                    situation, such as Mars, would it be worth while to
                                                    go all the way and also tailor the eyepieces to that
                                                    application? Photographers often choose a film to
                                                    compliment their subject.
                                                    ---

                                                    Would it be practical? I don't know. Thomas is the
                                                    one to provide that answer.

                                                    In concept, the answer is yes.

                                                    You certainly can, with modern computer design
                                                    software, compute correction distributed through the
                                                    whole system. Of course, you might no longer have any
                                                    interchangability outside of your system specific
                                                    components. But this might be OK for someone seeking
                                                    truly optimum performance.

                                                    But I don't know if there would be a benefit with
                                                    today's fine optics. Perhaps for some situations.

                                                    For planetary observation I doubt it. Optically, a
                                                    fine apo like a TMB is already about as good as you
                                                    can get on axis. So too with an eyepiece like the TMB
                                                    Monocentric, again on axis. Each is designed to stand
                                                    alone. But Tom would need to tell us if he could have
                                                    achieved a "sensible" gain if he had designed them
                                                    together. My guess is no, you could never perceive
                                                    the difference even if the design software said there
                                                    were a little bit.

                                                    For wide field viewing, my guess is their might be
                                                    something to gain. This is Thomas' forte! But if he
                                                    hasn't already investigated doing this, it might be
                                                    very time consuming for him to provide a difinitive
                                                    answer.

                                                    So Thomas, maybe someday when you have time?

                                                    There is an interesting historical question here too.
                                                    Perhaps Thomas can answer it too. Did any of the
                                                    early telescope makers like Fitz, Clark or Zeiss to
                                                    name a few (or modern manufacturers for that matter);
                                                    ever deliver astronomical telescopes where the
                                                    objective and eyepieces were optimized as a system and
                                                    needed to be used together?

                                                    Richard

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                                                  • wjburg
                                                    ... Richard, Every time I read a gripe about secondary color anywhere, I think was the instrument truly on axis when the observation was made. Thank you,
                                                    Message 25 of 28 , Oct 9, 2003
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                                                      --- In tmboptical@yahoogroups.com, Richard Chalfan <rchalfan@y...>
                                                      wrote:
                                                      > Bill,

                                                      >
                                                      > For planetary observation I doubt it. Optically, a
                                                      > fine apo like a TMB is already about as good as you
                                                      > can get on axis. So too with an eyepiece like the TMB
                                                      > Monocentric, again on axis. Each is designed to stand
                                                      > alone. But Tom would need to tell us if he could have
                                                      > achieved a "sensible" gain if he had designed them
                                                      > together. My guess is no, you could never perceive
                                                      > the difference even if the design software said there
                                                      > were a little bit.
                                                      >


                                                      Richard,

                                                      Every time I read a gripe about "secondary color" anywhere, I think
                                                      was the instrument truly on axis when the observation was made.

                                                      Thank you, bill
                                                    • tmboptical
                                                      ... I just want to say to all the TMB owners that are posting their terrific images a thank you. It is a true pleasure to see such wonderful photos. And I feel
                                                      Message 26 of 28 , Oct 21, 2003
                                                      • 0 Attachment
                                                        --- In tmboptical@yahoogroups.com, "digidodi" <ddierick@h...> wrote:
                                                        > I know what you are talking about... Mine with the TMB80mm was a
                                                        > nightmare to get it assembled and colorbalanced right. I used 3
                                                        > frames with CCD in France, and next one CCD color shot with Nikon
                                                        > lens and RGB filters from the center of Ghent. It's nice to compare
                                                        > though! Don't know if you have seen it, but here it is again:
                                                        >
                                                        > http://users.pandora.be/create/hotzone/galaxies/m31.htm
                                                        >
                                                        > D.

                                                        I just want to say to all the TMB owners that are posting their
                                                        terrific images a thank you. It is a true pleasure to see such
                                                        wonderful photos. And I feel the same way about all that post
                                                        their visual observations too. Bias aside, it makes this group
                                                        a great place to be.

                                                        Sincerely,

                                                        Thomas Back
                                                      • Michael Downing
                                                        No Tom, I think the thanks goes right back to you for your lens designs and dedication to your skill. Thank You Michael Downing www.astroden.com
                                                        Message 27 of 28 , Oct 22, 2003
                                                        • 0 Attachment
                                                          No Tom,
                                                          I think the thanks goes right back to you for your lens designs and
                                                          dedication to your skill.

                                                          Thank You
                                                          Michael Downing
                                                          www.astroden.com <http://www.astroden.com/>



                                                          -----Original Message-----
                                                          From: tmboptical [mailto:TMBoptical@...]
                                                          Sent: Wednesday, October 22, 2003 1:07 AM
                                                          To: tmboptical@yahoogroups.com
                                                          Subject: [tmboptical] Re: M31 mosaic with 4" TMB and the Canon 10D

                                                          --- In tmboptical@yahoogroups.com, "digidodi" <ddierick@h...> wrote:
                                                          > I know what you are talking about... Mine with the TMB80mm was a
                                                          > nightmare to get it assembled and colorbalanced right. I used 3
                                                          > frames with CCD in France, and next one CCD color shot with Nikon
                                                          > lens and RGB filters from the center of Ghent. It's nice to compare
                                                          > though! Don't know if you have seen it, but here it is again:
                                                          >
                                                          > http://users.pandora.be/create/hotzone/galaxies/m31.htm
                                                          >
                                                          > D.

                                                          I just want to say to all the TMB owners that are posting their
                                                          terrific images a thank you. It is a true pleasure to see such
                                                          wonderful photos. And I feel the same way about all that post
                                                          their visual observations too. Bias aside, it makes this group
                                                          a great place to be.

                                                          Sincerely,

                                                          Thomas Back





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                                                        • tmboptical
                                                          ... Thanks Michael, Sincerely, Thomas Back
                                                          Message 28 of 28 , Oct 24, 2003
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                                                            --- In tmboptical@yahoogroups.com, "Michael Downing" <michael@s...>
                                                            wrote:
                                                            > No Tom,
                                                            > I think the thanks goes right back to you for your lens designs and
                                                            > dedication to your skill.
                                                            >
                                                            > Thank You
                                                            > Michael Downing
                                                            > www.astroden.com <http://www.astroden.com/>

                                                            Thanks Michael,

                                                            Sincerely,

                                                            Thomas Back
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