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Finally, an update!

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  • parabola30
    Hi, Sorry for my absence lately, I have been continuing to organize my shop while running a bunch of mirrors through grind. That is done now and I can go into
    Message 1 of 12 , Apr 17 2:22 PM
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      Hi,

      Sorry for my absence lately, I have been continuing to organize my shop while running a bunch of mirrors through grind. That is done now and I can go into "polish mode" for a while, polishing out blanks and figuring some flats that need attention.

      I'm acquired another machine from Dick Wessling's former shop, and it has been put to immediate and frequent use. In the coming months I plan to add two more spindles for figuring smaller mirrors.

      --- In lockwood_optics@yahoogroups.com, hugues.laroche@... wrote:
      > These are really gorgeous pictures! This scope's make seems to be
      > very thorough.
      > I was just wondering why there were eight diffraction spikes, with
      > four major and four minor ones rotated 45 deg. Maybe the major
      > spikes some from the spider and the minor from the square secondary
      > frame?

      Hugues, I'm not quite sure - I'm guessing they're from cables that go to the camera/focuser that might not have been secured to the spider vanes yet.

      How is your 26" bino coming along? Do you have any photos to show?

      Mike Lockwood
      Lockwood Custom Optics
    • mdhopt53
      I had worked a 1.52 flat that came back from the coater. It was covered with tiny, sleeks, about fine hairline in width, and about 1/16th inch long oriented
      Message 2 of 12 , Apr 21 4:25 AM
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        I had worked a 1.52" flat that came back from the coater. It was covered with tiny, sleeks, about fine hairline in width, and about 1/16th inch long oriented in -ALL- directions, randomly distributed. There are so many, that I believe it may affect throughput somewhere between 5-10%

        When I made this, I polished it on urethane, until it was transparent to a laser. It came out about 16 fringes concave off the pellon polisher. Since I wasn't in a hurry, I spent 2 days in getting it flat, and finished it off with a stroke aligned with the long axis to get it flat.

        This thing had a ton of polishing on it. I mean it was squeaky clean and pristeen when it left here. I can't understand where all these sleeks came from. This thing was prolly meeting a 10/0 scratch/dig when it left here. The big mystery- the sleek orientation does -NOT- coincide with the finishing strokes used at the end of polishing.

        Ever have one come out like this, or have a similar problem? I've never seen this previously.

        (coater???? supposed to be very reputable-)

        Mark
      • parabola30
        Mark, I ve had some strange things show up on a mirror, but it turned out the paper towel I had over the surface had left a residue, and the coater was able to
        Message 3 of 12 , Apr 21 5:52 PM
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          Mark,

          I've had some strange things show up on a mirror, but it turned out the paper towel I had over the surface had left a residue, and the coater was able to figure it out and remove it. Now it's acid-free paper over every surface before shipping.

          Mike Lockwood
          Lockwood Custom Optics

          --- In lockwood_optics@yahoogroups.com, "mdhopt53" <harrymark7@...> wrote:
          > This thing had a ton of polishing on it. I mean it was squeaky clean and pristeen when it left here. I can't understand where all these sleeks came from. This thing was prolly meeting a 10/0 scratch/dig when it left here. The big mystery- the sleek orientation does -NOT- coincide with the finishing strokes used at the end of polishing.
          >
          > Ever have one come out like this, or have a similar problem? I've never seen this previously.
          > (coater???? supposed to be very reputable-)
        • mdhopt53
          Now it s acid-free paper over every surface before shipping. Hmmm, that s rather odd, considering borosilicate substrates are resistant to acids, but more
          Message 4 of 12 , Apr 22 4:42 AM
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            " Now it's acid-free paper over every surface before shipping."


            Hmmm, that's rather odd, considering borosilicate substrates are resistant to acids, but more susceptible to alkalis. This can be found on the Schott site. Perhaps the paper towel was contaminated???

            ***
            I'm thinking my diagonal was possibly "altered", since these sleeks didn't leave here when shipped out...
            Some mysteries never get solved.
            Thanks, Mike
          • Aurigema, Andrew N. (KSC-ASRC-491)[ASRC A
            For the novice mirror makers that follow this thread, could you explain what a sleek looks like ??? I have coated quite a few mirrors now and some very odd
            Message 5 of 12 , Apr 22 5:42 AM
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              For the novice mirror makers that follow this thread, could you explain what a “sleek” looks like ???  I have coated quite a few mirrors now and some very odd things show up with 120 nm of aluminum on them that I never saw going in the chamber.   

               

              Drew in sunny Florida

               

              From: lockwood_optics@yahoogroups.com [mailto:lockwood_optics@yahoogroups.com] On Behalf Of mdhopt53
              Sent: Thursday, April 22, 2010 7:42 AM
              To: lockwood_optics@yahoogroups.com
              Subject: [lockwood_optics] Re: speaking of elliptical flats-

               

               

              " Now it's acid-free paper over every surface before shipping."

              Hmmm, that's rather odd, considering borosilicate substrates are resistant to acids, but more susceptible to alkalis. This can be found on the Schott site. Perhaps the paper towel was contaminated???

              ***
              I'm thinking my diagonal was possibly "altered", since these sleeks didn't leave here when shipped out...
              Some mysteries never get solved.
              Thanks, Mike

            • parabola30
              Mark, ... It was right off the roll, but who knows what is in there. I take no chances now. ... I suspect you are right. My recommendation for coaters is to
              Message 6 of 12 , Apr 22 12:04 PM
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                Mark,

                --- In lockwood_optics@yahoogroups.com, "mdhopt53" <harrymark7@...> wrote:
                > Hmmm, that's rather odd, considering borosilicate substrates are
                > resistant to acids, but more susceptible to alkalis. This can be
                > found on the Schott site. Perhaps the paper towel was
                > contaminated???

                It was right off the roll, but who knows what is in there. I take no chances now.

                > I'm thinking my diagonal was possibly "altered", since these sleeks didn't leave here when shipped out...

                I suspect you are right. My recommendation for coaters is to use those who have experience making optical surfaces, because they will treat them properly. Currently I use Nova Optical Systems for coating up to 20" mirrors, and OMI for 22" through 46" optics.

                --- In lockwood_optics@yahoogroups.com, "Aurigema, Andrew N. (KSC-ASRC-491)[ASRC AEROSPACE]" <andrew.n.aurigema@...> wrote:
                > For the novice mirror makers that follow this thread, could you
                > explain what a "sleek" looks like ??? I have coated quite a few
                > mirrors now and some very odd things show up with 120 nm of
                > aluminum on them that I never saw going in the chamber.

                A sleek is a very, very fine scratch. They are difficult to see on an uncoated, polished surface unless you use an inspection light and try to put some dark material under the mirror to minimize light reflecting from below.

                The good news is that a few sleeks basically have no effect on optical performance. They can be caused by polishing compound itself or by certain figuring techniques.

                They are NOT a reason to refigure a mirror (unless there are a large number of them), but it is certainly something I try to avoid, and most of the time I am successful.

                Mike Lockwood
                Lockwood Custom Optics
              • mdhopt53
                Also, to describe a sleek; which is a miniscule scratch, can be polished off in just a few minutes. Generally, they are encountered in glass that are used for
                Message 7 of 12 , Apr 23 4:23 AM
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                  Also, to describe a sleek; which is a miniscule scratch, can be polished off in just a few minutes. Generally, they are encountered in glass that are used for lenses, etc. They are sort of rare to come across with pyrex and like substrates. (At least IME.)
                  M.
                • Aurigema, Andrew N. (KSC-ASRC-491)[ASRC A
                  Thanks Mike, Remember that if you just want to test out a mirror with a test coating you can send it to me way less than OMI. Hey did I mention that I am
                  Message 8 of 12 , Apr 23 4:52 AM
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                    Thanks Mike,

                     

                    Remember that if you just want to test out a mirror with a test coating you can send it to me way less than OMI. 

                     

                    Hey did I mention that I am trying out a wipe on SiO2 coating from Germany ???  It self aligns to form an 80 nm thick SiO2 layer of crystline glass.  That is exactly what is needed for overcoating of aluminum.  I know it sounds like “foo-foo magic” but the scanning electron microcope images they post warranted the experiment.  This could be what brings back silver on mirrors. 

                     

                    Drew in sunny Florida

                    ---------------------------------------------------------------------------

                    A sleek is a very, very fine scratch. They are difficult to see on an uncoated, polished surface unless you use an inspection light and try to put some dark material under the mirror to minimize light reflecting from below.

                    The good news is that a few sleeks basically have no effect on optical performance. They can be caused by polishing compound itself or by certain figuring techniques.

                    They are NOT a reason to refigure a mirror (unless there are a large number of them), but it is certainly something I try to avoid, and most of the time I am successful.

                    Mike Lockwood
                    Lockwood Custom Optics

                  • radicell2
                    ... Any web links? Ric
                    Message 9 of 12 , Apr 23 6:36 AM
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                      --- In lockwood_optics@yahoogroups.com, "Aurigema, Andrew N. (KSC-ASRC-491)[ASRC AEROSPACE]" <andrew.n.aurigema@...> wrote:

                      >
                      > Hey did I mention that I am trying out a wipe on SiO2 coating from Germany ??? It self aligns to form an 80 nm thick SiO2 layer of crystline glass. That is exactly what is needed for overcoating of aluminum. I know it sounds like "foo-foo magic" but the scanning electron microcope images they post warranted the experiment. This could be what brings back silver on mirrors.
                      >

                      Any web links?

                      Ric
                    • Aurigema, Andrew N. (KSC-ASRC-491)[ASRC A
                      Mike, Do you mind if I post the link to the German company ??? I don t want to take your posting off on a tangent without official yup from the master
                      Message 10 of 12 , Apr 23 7:50 AM
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                        Mike,

                         

                        Do you mind if I post the link to the German company ???  I don’t want to take your posting off on a tangent without official “yup” from the master :_)))))

                         

                        Drew

                         

                        From: lockwood_optics@yahoogroups.com [mailto:lockwood_optics@yahoogroups.com] On Behalf Of radicell2
                        Sent: Friday, April 23, 2010 9:37 AM
                        To: lockwood_optics@yahoogroups.com
                        Subject: [lockwood_optics] Re: speaking of elliptical flats-

                         

                         
                        --- In lockwood_optics@yahoogroups.com, "Aurigema, Andrew N. (KSC-ASRC-491)[ASRC AEROSPACE]" <andrew.n.aurigema@...> wrote:

                        >
                        > Hey did I mention that I am trying out a wipe on SiO2 coating from Germany
                        ??? It self aligns to form an 80 nm thick SiO2 layer of crystline glass. That is exactly what is needed for overcoating of aluminum. I know it sounds like "foo-foo magic" but the scanning electron microcope images they post warranted the experiment. This could be what brings back silver on mirrors.
                        >

                        Any web links?

                        Ric

                      • parabola30
                        Andrew, ... You mean a sacrificial coating. Yes, Andrew has a large coating chamber that can put on aluminum. Keep in mind, this is not a commercial
                        Message 11 of 12 , Apr 23 8:49 PM
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                          Andrew,

                          --- In lockwood_optics@yahoogroups.com, "Aurigema, Andrew N. (KSC-ASRC-491)[ASRC AEROSPACE]" <andrew.n.aurigema@...> wrote:
                          > Remember that if you just want to test out a mirror with a test coating you can send it to me way less than OMI.

                          You mean a "sacrificial" coating. Yes, Andrew has a large coating chamber that can put on aluminum. Keep in mind, this is not a commercial venture, but it does pull vacuum and sling metal pretty well. Andrew's got a shop that would make most ATMs foam at the mouth with envy.

                          > Hey did I mention that I am trying out a wipe on SiO2 coating from Germany ??? It self aligns to form an 80 nm thick SiO2 layer of crystline glass. That is exactly what is needed for overcoating of aluminum. I know it sounds like "foo-foo magic" but the scanning electron microcope images they post warranted the experiment.

                          You can post a link as long as you include a link to some sort of proof that it shows promise.

                          I don't endorse such products or use them myself, but it sounds like an interesting experiment to run. Wipe some on a mirror, Andrew, and put it out in the Florida elements and see how it holds up.

                          Still sounds like foo-foo to me, though.

                          Mike Lockwood
                          Lockwood Custom Optics
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