Loading ...
Sorry, an error occurred while loading the content.

Re: Mirror Making event

Expand Messages
  • Jerry Truitt
    I would be interested in doing it. I contacted Newport Glass they said they would e-mail me a quote but I have not received it yet. I also talked to Dr.
    Message 1 of 6 , Nov 30, 2004
    • 0 Attachment
          I would be interested in doing it. I contacted Newport Glass they said they would e-mail me a quote but I have not received it yet. I also talked to Dr. Hanagan who said he would be willing to participate.
          However I agree if we don't have enough enthusiasm to even respond we should cancel the event and not leave people hanging.
    • David M Groski
      The 4.25 Schiefspegler or Schief for short or sometimes called Sheepspringler is all spherical tilted optics telescope. It is unique in that the both the
      Message 2 of 6 , Dec 2, 2004
      • 0 Attachment
        The 4.25" Schiefspegler or Schief for short or sometimes called
        'Sheepspringler' is all spherical tilted optics telescope. It is unique in
        that the both the primary mirror and secondary mirror have the same but
        opposite sign radius of curvature. What this means is that the convex tool
        used to grind the concave primary becomes the secondary. Once the primary
        is figured to a sphere it is used the test the figure on the secondary by
        interference. The light path is unobstructed and the F-ratio is 27. The
        'scope is designed for high resolution lunar,planetary and double star
        work. It performs as well or better then a refractor and has no color. I
        took the original Anton Kutter design that was published back in the 1961
        and used a program that tweaked it. The original design had about 1/4 of
        residue coma. In my design this had been reduced to below 1/10 wave. Bill
        Cheng has built one and it was displayed at last years Mirror Making class.
        It gave some truly excellent images. He had it this years Stellafane.
        Unfortunately the skies weren't clear long enough for a form optical
        judging, but a number of people including the former head of the optically
        judging committee did look through it and stated that it star tested
        perfectly. It was one of the possible projects for a future mirror making
        event.

        - Dave



        This communication is for use by the intended recipient and contains
        information that may be privileged, confidential or copyrighted under
        applicable law. If you are not the intended recipient, you are hereby
        formally notified that any use, copying or distribution of this e-mail,
        in whole or in part, is strictly prohibited. Please notify the sender
        by return e-mail and delete this e-mail from your system. Unless
        explicitly and conspicuously designated as "E-Contract Intended",
        this e-mail does not constitute a contract offer, a contract amendment,
        or an acceptance of a contract offer. This e-mail does not constitute
        a consent to the use of sender's contact information for direct marketing
        purposes or for transfers of data to third parties.

        Francais Deutsch Italiano Espanol Portugues Japanese Chinese Korean

        http://www.DuPont.com/corp/email_disclaimer.html
      • Tom Dove
        I might be interested; last year s seminar was a lot of fun and I m thoroughly enjoying my 6 f/8 Dob that I ground the mirror for there. I must have missed
        Message 3 of 6 , Dec 2, 2004
        • 0 Attachment
          I might be interested; last year's seminar was a lot of fun and I'm thoroughly enjoying my
          6" f/8 Dob that I ground the mirror for there. I must have missed the announcement in the
          newsletter for the next event.

          What projects are proposed? By springtime, cabin fever should have me ready for another
          project as long as it doesn't duplicate something I already have.

          -- Tom Dove
        • James T. Morgan
          Thanks for the explanation, this sounds cool but at F27 how long is the scope? Can you remove the central obstruction in a regular Newtonian by tilting the
          Message 4 of 6 , Dec 3, 2004
          • 0 Attachment
            Thanks for the explanation, this sounds cool but at
            F27 how long is the scope?

            Can you remove the central obstruction in a regular
            Newtonian by tilting the optics? This intrigues me
            and I suspect that it introduces a host of other
            problems so it is not so easy to do. Just wondering
            how wonderful it would be to gain that area back for
            viewing.

            James




            __________________________________
            Do you Yahoo!?
            Jazz up your holiday email with celebrity designs. Learn more.
            http://celebrity.mail.yahoo.com
          • David M Groski
            James, The optical path is folded and the secondary amplifies. The scope is about 3 long. There are pictures of Bill s scope on the Stellafane s website
            Message 5 of 6 , Dec 3, 2004
            • 0 Attachment
              James,
              The optical path is folded and the secondary amplifies. The 'scope is
              about 3' long. There are pictures of Bill's 'scope on the Stellafane's
              website under 'All scope entered .... " for 2004. Both the primary and
              secondary are tilted so they cancel out the aberrations introduced by
              tilting. Planetary detail is very sharp. I know a number of people looked
              through Bill's scope at last year's mirror making class and were very
              impressed with the quality.
              Herschel was the first to tilt the primary on a Newtonian to get read of
              the secondary. This only works well for a f/35 or longer system up to about
              a 6" mirror, but it also leads to a really long tube !



              "James T. Morgan"
              <morganjt56@yahoo
              .com> To
              delmarvastargazers@yahoogroups.com
              12/03/2004 10:20 cc
              AM
              Subject
              [delmarvastargazers] Mirror Making
              Please respond to event scheifspegler
              delmarvastargazer
              s@yahoogroups.com









              Thanks for the explanation, this sounds cool but at
              F27 how long is the scope?

              Can you remove the central obstruction in a regular
              Newtonian by tilting the optics? This intrigues me
              and I suspect that it introduces a host of other
              problems so it is not so easy to do. Just wondering
              how wonderful it would be to gain that area back for
              viewing.

              James




              __________________________________
              Do you Yahoo!?
              Jazz up your holiday email with celebrity designs. Learn more.
              http://celebrity.mail.yahoo.com




              Yahoo! Groups Links











              This communication is for use by the intended recipient and contains
              information that may be privileged, confidential or copyrighted under
              applicable law. If you are not the intended recipient, you are hereby
              formally notified that any use, copying or distribution of this e-mail,
              in whole or in part, is strictly prohibited. Please notify the sender
              by return e-mail and delete this e-mail from your system. Unless
              explicitly and conspicuously designated as "E-Contract Intended",
              this e-mail does not constitute a contract offer, a contract amendment,
              or an acceptance of a contract offer. This e-mail does not constitute
              a consent to the use of sender's contact information for direct marketing
              purposes or for transfers of data to third parties.

              Francais Deutsch Italiano Espanol Portugues Japanese Chinese Korean

              http://www.DuPont.com/corp/email_disclaimer.html
            Your message has been successfully submitted and would be delivered to recipients shortly.