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Re: Monocentric eyepiece eye relief?

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  • Tony White <twhite@digitania.net>
    ... Somehow I just knew I d be wrong. :) I ve had a couple of 4mm Orthos (Vixen and Meade RG) and have the 4mm Clave, and have no trouble with eye relief out
    Message 1 of 16 , Feb 28, 2003
      > That was true with my first design that had a glass that was too
      > expensive to use in production. The new design, which gives up
      > nothing in sharpness and contrast, has a 0.8 x the focal length
      > of eye relief. This is still more than a Plossl or orthoscopic.
      >
      > 4mm = 3.2mm
      > 6mm = 4.8mm
      > 8mm = 6.4mm
      > 10mm = 8.0mm
      >
      > The field of view is 30 degrees. This will give the observer
      > a feeling of greater eyerelief than the numbers above. But
      > again, we are not going to compromise performance, for a large
      > field or 20mm of eyerelief. There are plenty of eyepieces
      > on the market that achieve that, but they lack the critical
      > contrast of a superior designed and manufactured Monocentric
      > eyepiece. I personally have no trouble using the Zeiss Abbe
      > 4mm orthoscopic.

      Somehow I just knew I'd be wrong. :)

      I've had a couple of 4mm Orthos (Vixen and Meade RG) and have the
      4mm Clave, and have no trouble with eye relief out of either of
      those. This almost sounds generous by comparison. :)

      regards,

      twhite
    • Markus Ludes
      the eyepieces will be physical like a Pentax SMC Ortho with 1.25 barrel Markus ... From: ronbee77 To: tmboptical@yahoogroups.com Sent:
      Message 2 of 16 , Mar 1, 2003
        the eyepieces will be physical like a Pentax SMC Ortho with 1.25" barrel

        Markus
        ----- Original Message -----
        From: ronbee77 <ronby@...>
        To: tmboptical@yahoogroups.com
        Sent: Saturday, March 01, 2003 7:30 AM
        Subject: [tmboptical] Re: Monocentric eyepiece eye relief?


        --- In tmboptical@yahoogroups.com, "tmboptical <TMBoptical@a...>"
        <TMBoptical@a...> wrote:
        >
        > 4mm = 3.2mm
        > 6mm = 4.8mm
        > 8mm = 6.4mm
        > 10mm = 8.0mm
        >
        > The field of view is 30 degrees. This will give the observer
        > a feeling of greater eyerelief than the numbers above. But
        > again, we are not going to compromise performance, for a large
        > field or 20mm of eyerelief. There are plenty of eyepieces
        > on the market that achieve that, but they lack the critical
        > contrast of a superior designed and manufactured Monocentric
        > eyepiece. I personally have no trouble using the Zeiss Abbe
        > 4mm orthoscopic.
        >
        > Thomas Back

        Oh no, no 5mm?

        Will the eyepiece physically be like "cone-like" where the exit pupil
        goes like the UO Ortho? I understand this physical design help
        greatly with short eye relief?

        Thanks,
        Ron B[ee]



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      • Mike Fowler <popocatept@aol.com>
        - ... snip ... snip, snip ... snip ... I too think that a 5 piece set with a 5mm is needed. If finances or other reasons preclude it now, can it be added
        Message 3 of 16 , Mar 1, 2003
          -
          > <TMBoptical@a...> wrote:
          > >
          snip
          > > 4mm = 3.2mm
          > > 6mm = 4.8mm
          > > 8mm = 6.4mm
          > > 10mm = 8.0mm
          snip, snip
          > > Thomas Back
          >
          > Oh no, no 5mm?
          snip
          > Thanks,
          > Ron B[ee]

          I too think that a 5 piece set with a 5mm is needed. If finances or
          other reasons preclude it now, can it be added later?

          Mike Fowler
          Chicago
        • tmboptical <TMBoptical@aol.com>
          ... BTW Ron, thanks for the kind words on s.a.a. ... Mike, Ron and everyone else interested in the eyepieces, If the TMB Mono eyepiece project is successful,
          Message 4 of 16 , Mar 1, 2003
            --- In tmboptical@yahoogroups.com, "Mike Fowler <popocatept@a...>"
            <popocatept@a...> wrote:
            > > Oh no, no 5mm?
            > snip
            > > Thanks,
            > > Ron B[ee]

            BTW Ron, thanks for the kind words on s.a.a.

            > I too think that a 5 piece set with a 5mm is needed. If
            > finances or other reasons preclude it now, can it be added
            > later?
            >
            > Mike Fowler
            > Chicago

            Mike, Ron and everyone else interested in the eyepieces,

            If the TMB Mono eyepiece project is successful, I'm sure we will
            be able to add a 5mm to the set. Time will tell. Thanks for your
            input, and believe me, I want a 5mm just as much as you guys do!

            On the subject of the TMB Monocentrics, I have received so many
            e-mail's to be put on the contact list, I simply do not have the
            time to answer in detail, every e-mail. Rest assured that each
            person that contacted me will definitely be on the list. Please
            don't be offended if I reply to each person with a form letter
            acknowledging that you are on the list. Thank you.

            Thomas Back
          • phbjr@aol.com
            In a message dated 3/1/03 7:22:32 PM Eastern Standard Time, TMBoptical@aol.com writes:
            Message 5 of 16 , Mar 1, 2003
              In a message dated 3/1/03 7:22:32 PM Eastern Standard Time,
              TMBoptical@... writes:

              << On the subject of the TMB Monocentrics, I have received so many
              e-mail's to be put on the contact list, I simply do not have the
              time to answer in detail, every e-mail.

              Thomas,

              The list already includes everyone who answered in the affirmative to
              the poll taken back in December/January, correct?

              PaulB



              [Non-text portions of this message have been removed]
            • izar21093 <izar@juno.com>
              Senior moment here. I do not know if I am on the eyepiece list or not. If not, please include my name. Bill G
              Message 6 of 16 , Mar 1, 2003
                Senior moment here. I do not know if I am on the eyepiece list or not.

                If not, please include my name.

                Bill G
                *****


                --- In tmboptical@yahoogroups.com, "tmboptical <TMBoptical@a...>"
                <TMBoptical@a...> wrote:
                > --- In tmboptical@yahoogroups.com, "Mike Fowler <popocatept@a...>"
                > <popocatept@a...> wrote:
                > > > Oh no, no 5mm?
                > > snip
                > > > Thanks,
                > > > Ron B[ee]
                >
                > BTW Ron, thanks for the kind words on s.a.a.
                >
                > > I too think that a 5 piece set with a 5mm is needed. If
                > > finances or other reasons preclude it now, can it be added
                > > later?
                > >
                > > Mike Fowler
                > > Chicago
                >
                > Mike, Ron and everyone else interested in the eyepieces,
                >
                > If the TMB Mono eyepiece project is successful, I'm sure we will
                > be able to add a 5mm to the set. Time will tell. Thanks for your
                > input, and believe me, I want a 5mm just as much as you guys do!
                >
                > On the subject of the TMB Monocentrics, I have received so many
                > e-mail's to be put on the contact list, I simply do not have the
                > time to answer in detail, every e-mail. Rest assured that each
                > person that contacted me will definitely be on the list. Please
                > don't be offended if I reply to each person with a form letter
                > acknowledging that you are on the list. Thank you.
                >
                > Thomas Back
              • Larry Geary
                ... No. That poll only counted heads. There was no way to capture names or email addresses. --Larry
                Message 7 of 16 , Mar 1, 2003
                  > Thomas,
                  >
                  > The list already includes everyone who answered in the
                  > affirmative to
                  > the poll taken back in December/January, correct?
                  >
                  > PaulB


                  No. That poll only counted heads. There was no way to capture names or email
                  addresses.

                  --Larry
                • cjamescook
                  ... ... Okay, I ll bite on this one: On one hand, exotic glasses can be hundreds of dollars per kilo. This is expensive if you are building a primary
                  Message 8 of 16 , Apr 17, 2003
                    > --- In tmboptical@yahoogroups.com, "Tony White <twhite@d...>"
                    > <twhite@d...> wrote:
                    > >
                    > > A while back (message 6173) Tom said that the Steinheil
                    > > monocentric's eye relief ratio was about .85. Assuming his
                    > > designs won't vary from that, I get:

                    <snip>

                    > > I assume Markus or Tom will correct me if I'm wrong. :)

                    --- In tmboptical@yahoogroups.com, "tmboptical <TMBoptical@a...>"
                    <TMBoptical@a...> replied:

                    > That was true with my first design that had a glass that was too
                    > expensive to use in production.

                    Okay, I'll bite on this one:
                    On one hand, exotic glasses can be hundreds of dollars per kilo. This
                    is expensive if you are building a primary objective. But here we are
                    talking about eyepieces, where the lenses are fractions of an ounce
                    (excuse the mixed units).

                    So for us armchair opticians, living vicariously through your
                    experiences and reports, how expensive can that be?

                    Take this as a general question if you wish: Just how expensive do
                    those exotic glasses get, generally speaking?

                    Cheers!
                    -Jim Cook
                    Bolton, Massachusetts, USA
                  • Markus Ludes
                    Jim, excotic glas is not only way more expensive, its also a bit more difficult to polish. More info Tom Back can get to you best wishes Markus ... From:
                    Message 9 of 16 , Apr 17, 2003
                      Jim, excotic glas is not only way more expensive, its also a bit more difficult to polish. More info Tom Back can get to you

                      best wishes
                      Markus
                      ----- Original Message -----
                      From: cjamescook
                      To: tmboptical@yahoogroups.com
                      Sent: Thursday, April 17, 2003 8:31 PM
                      Subject: [tmboptical] Re: Monocentric eyepiece eye relief?



                      > --- In tmboptical@yahoogroups.com, "Tony White <twhite@d...>"
                      > <twhite@d...> wrote:
                      > >
                      > > A while back (message 6173) Tom said that the Steinheil
                      > > monocentric's eye relief ratio was about .85. Assuming his
                      > > designs won't vary from that, I get:

                      <snip>

                      > > I assume Markus or Tom will correct me if I'm wrong. :)

                      --- In tmboptical@yahoogroups.com, "tmboptical <TMBoptical@a...>"
                      <TMBoptical@a...> replied:

                      > That was true with my first design that had a glass that was too
                      > expensive to use in production.

                      Okay, I'll bite on this one:
                      On one hand, exotic glasses can be hundreds of dollars per kilo. This
                      is expensive if you are building a primary objective. But here we are
                      talking about eyepieces, where the lenses are fractions of an ounce
                      (excuse the mixed units).

                      So for us armchair opticians, living vicariously through your
                      experiences and reports, how expensive can that be?

                      Take this as a general question if you wish: Just how expensive do
                      those exotic glasses get, generally speaking?

                      Cheers!
                      -Jim Cook
                      Bolton, Massachusetts, USA




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                      ADVERTISEMENT




                      To unsubscribe from this group, send an email to:
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                      [Non-text portions of this message have been removed]
                    • tmboptical
                      ... This ... are ... Jim, You will have to ask Markus for the exact pricing, but it would have raised the price of the eyepiece, and the glass was very
                      Message 10 of 16 , Apr 17, 2003
                        --- In tmboptical@yahoogroups.com, "cjamescook" <jimcook@a...> wrote:
                        >
                        > > --- In tmboptical@yahoogroups.com, "Tony White <twhite@d...>"
                        > > <twhite@d...> wrote:
                        > > >
                        > > > A while back (message 6173) Tom said that the Steinheil
                        > > > monocentric's eye relief ratio was about .85. Assuming his
                        > > > designs won't vary from that, I get:
                        >
                        > <snip>
                        >
                        > > > I assume Markus or Tom will correct me if I'm wrong. :)
                        >
                        > --- In tmboptical@yahoogroups.com, "tmboptical <TMBoptical@a...>"
                        > <TMBoptical@a...> replied:
                        >
                        > > That was true with my first design that had a glass that was too
                        > > expensive to use in production.
                        >
                        > Okay, I'll bite on this one:
                        > On one hand, exotic glasses can be hundreds of dollars per kilo.
                        This
                        > is expensive if you are building a primary objective. But here we
                        are
                        > talking about eyepieces, where the lenses are fractions of an ounce
                        > (excuse the mixed units).
                        >
                        > So for us armchair opticians, living vicariously through your
                        > experiences and reports, how expensive can that be?
                        >
                        > Take this as a general question if you wish: Just how expensive do
                        > those exotic glasses get, generally speaking?
                        >
                        > Cheers!
                        > -Jim Cook
                        > Bolton, Massachusetts, USA

                        Jim,

                        You will have to ask Markus for the exact pricing, but it would
                        have raised the price of the eyepiece, and the glass was very
                        difficult to work with, i.e., staining. The replacement glass
                        is still an high index glass, and no performance is lost. The
                        eye relief dropped from .85x to .80x, better than any ortho or
                        Plossl. And the prototype worked so well, that Markus was using
                        it with a ~40 degree field (no field stop), and it still had
                        good eyerelief for a 6mm eyepiece. Because the design is so sharp
                        out to a 40 AFOV, we have decided to increase the field from 30
                        degrees to 35 degrees, and the eyerelief will be even better
                        than what Markus experienced, at 40 degrees AFOV.

                        Thomas Back
                      • cjamescook
                        ... Clearly I only focused on the price of the glass and not the cost of working the glass. Obviously, I need to be more practical, thinking more like running
                        Message 11 of 16 , Apr 17, 2003
                          > > --- In tmboptical@yahoogroups.com, "tmboptical <TMBoptical@a...>"
                          > > <TMBoptical@a...> replied:
                          > >
                          > > > That was true with my first design that had a glass that was too
                          > > > expensive to use in production.
                          > >

                          --- In tmboptical@yahoogroups.com, "cjamescook" <jimcook@a...>
                          replied:

                          > > So for us armchair opticians, living vicariously through your
                          > > experiences and reports, how expensive can that be?
                          > >
                          > > Take this as a general question if you wish: Just how expensive
                          > > do those exotic glasses get, generally speaking?

                          --- In tmboptical@yahoogroups.com, "tmboptical" <TMBoptical@a...>
                          replied:

                          > You will have to ask Markus for the exact pricing, but it would
                          > have raised the price of the eyepiece, and the glass was very
                          > difficult to work with, i.e., staining. The replacement glass
                          > is still an high index glass, and no performance is lost. The
                          > eye relief dropped from .85x to .80x, better than any ortho or
                          > Plossl. And the prototype worked so well, that Markus was using
                          > it with a ~40 degree field (no field stop), and it still had
                          > good eyerelief for a 6mm eyepiece. Because the design is so sharp
                          > out to a 40 AFOV, we have decided to increase the field from 30
                          > degrees to 35 degrees, and the eyerelief will be even better
                          > than what Markus experienced, at 40 degrees AFOV.

                          Clearly I only focused on the price of the glass and not the cost of
                          working the glass. Obviously, I need to be more practical, thinking
                          more like running a business, and less of a purist.

                          Thanks for taking the time to answer.

                          -Jim
                        • phbjr@aol.com
                          In a message dated 4/17/03 5:20:29 PM Eastern Daylight Time, TMBoptical@aol.com writes:
                          Message 12 of 16 , Apr 17, 2003
                            In a message dated 4/17/03 5:20:29 PM Eastern Daylight Time,
                            TMBoptical@... writes:

                            << The eye relief dropped from .85x to .80x, better than any ortho or Plossl.

                            Is the "rule of thumb" for orthoscopics around 0.75x? (I'm basing
                            that on the stated eye relief of the Antares orthos). What is it for
                            Plossls?

                            Paul Bock



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