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Mars sketches from giant refractor - FYI

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  • ronbee77
    http://mtham.ucolick.org/public/TwoWeeksOnMars/drawings/ Awesome, ain t it! And a nice writeup... http://mtham.ucolick.org/public/TwoWeeksOnMars/writings/
    Message 1 of 23 , Oct 21, 2003
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      http://mtham.ucolick.org/public/TwoWeeksOnMars/drawings/
      Awesome, ain't it! And a nice writeup...
      http://mtham.ucolick.org/public/TwoWeeksOnMars/writings/
      Note how the 36-inch was stopped down to 20-inch to control the
      chromatic aberrations.

      Ron B[ee]
    • izar21093
      Thanks Ron[Bee}, Where do you find such good stuff?? Bill G
      Message 2 of 23 , Oct 21, 2003
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        Thanks Ron[Bee},

        Where do you find such good stuff??

        Bill G
        *****


        --- In tmboptical@yahoogroups.com, "ronbee77" <ronby@c...> wrote:
        > http://mtham.ucolick.org/public/TwoWeeksOnMars/drawings/
        > Awesome, ain't it! And a nice writeup...
        > http://mtham.ucolick.org/public/TwoWeeksOnMars/writings/
        > Note how the 36-inch was stopped down to 20-inch to control the
        > chromatic aberrations.
        >
        > Ron B[ee]
      • izar21093
        Now,,, a 36 TMB APO..................................
        Message 3 of 23 , Oct 21, 2003
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          Now,,, a 36" TMB APO..................................


          --- In tmboptical@yahoogroups.com, "ronbee77" <ronby@c...> wrote:
          > http://mtham.ucolick.org/public/TwoWeeksOnMars/drawings/
          > Awesome, ain't it! And a nice writeup...
          > http://mtham.ucolick.org/public/TwoWeeksOnMars/writings/
          > Note how the 36-inch was stopped down to 20-inch to control the
          > chromatic aberrations.
          >
          > Ron B[ee]
        • ronbee77
          ... You re welcome, Bill. Alas, a good reporter may not reveal his/her sources ;-). Ron B[ee]
          Message 4 of 23 , Oct 21, 2003
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            --- In tmboptical@yahoogroups.com, "izar21093" <izar@j...> wrote:
            > Thanks Ron[Bee},
            >
            > Where do you find such good stuff??
            >
            > Bill G
            > *****

            You're welcome, Bill. Alas, a good reporter may not reveal his/her
            sources ;-).

            Ron B[ee]
          • tmboptical
            ... Hi Ron, Great web site, and Mars drawings. Thanks a lot for posting it, I ve book marked it. Thomas Back
            Message 5 of 23 , Oct 21, 2003
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              --- In tmboptical@yahoogroups.com, "ronbee77" <ronby@c...> wrote:
              > http://mtham.ucolick.org/public/TwoWeeksOnMars/drawings/
              > Awesome, ain't it! And a nice writeup...
              > http://mtham.ucolick.org/public/TwoWeeksOnMars/writings/
              > Note how the 36-inch was stopped down to 20-inch to control the
              > chromatic aberrations.
              >
              > Ron B[ee]

              Hi Ron,

              Great web site, and Mars drawings. Thanks a lot for posting
              it, I've book marked it.

              Thomas Back
            • tmboptical
              ... Last week I had a phone conversation with Markus, and I asked what was the largest TMB apo LZOS could make. The reason was because an institution is
              Message 6 of 23 , Oct 21, 2003
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                --- In tmboptical@yahoogroups.com, "izar21093" <izar@j...> wrote:
                > Now,,, a 36" TMB APO..................................
                >

                Last week I had a phone conversation with Markus, and I asked
                what was the largest TMB apo LZOS could make. The reason was
                because an institution is interested in the largest apochromatic
                refractor that could be built. Markus said that the glass was
                not the limitation, but the focal length. This is because of
                the autocollimation test setup. So, it is really up to me to come
                up with a superior design, that would correct aberrations at a
                relatively fast focal ratio. So far I have a 24" design that
                would work. Not bad, but I don't think a 36" is in the cards. :-)

                Thomas Back
              • Mike C
                ... Wow! Curious Indeed... What focal ratio was the 24 ? Mike
                Message 7 of 23 , Oct 22, 2003
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                  >
                  > Last week I had a phone conversation with Markus, and I asked
                  > what was the largest TMB apo LZOS could make. The reason was
                  > because an institution is interested in the largest apochromatic
                  > refractor that could be built. Markus said that the glass was
                  > not the limitation, but the focal length. This is because of
                  > the autocollimation test setup. So, it is really up to me to come
                  > up with a superior design, that would correct aberrations at a
                  > relatively fast focal ratio. So far I have a 24" design that
                  > would work. Not bad, but I don't think a 36" is in the cards. :-)
                  >
                  > Thomas Back


                  Wow! Curious Indeed... What focal ratio was the 24"?

                  Mike
                • jimhp29401us
                  WSow! This is great stuff. I m going to have to porint this off and save it. Thank you veryt much! Jim Phillips
                  Message 8 of 23 , Oct 22, 2003
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                    WSow! This is great stuff. I'm going to have to porint this off and
                    save it. Thank you veryt much!

                    Jim Phillips


                    > Awesome, ain't it! And a nice writeup...
                    > http://mtham.ucolick.org/public/TwoWeeksOnMars/writings/
                    > Note how the 36-inch was stopped down to 20-inch to control the
                    > chromatic aberrations.
                    >
                    > Ron B[ee]
                  • Michael Downing
                    WOW! I would love to have a session with that scope :-) Michael Downing www.astroden.com ... From: ronbee77 [mailto:ronby@cox.net]
                    Message 9 of 23 , Oct 22, 2003
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                      WOW!
                      I would love to have a session with that scope :-)

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



                      -----Original Message-----
                      From: ronbee77 [mailto:ronby@...]
                      Sent: Tuesday, October 21, 2003 6:45 PM
                      To: tmboptical@yahoogroups.com
                      Subject: [tmboptical] Mars sketches from giant refractor - FYI

                      http://mtham.ucolick.org/public/TwoWeeksOnMars/drawings/
                      Awesome, ain't it! And a nice writeup...
                      http://mtham.ucolick.org/public/TwoWeeksOnMars/writings/
                      Note how the 36-inch was stopped down to 20-inch to control the
                      chromatic aberrations.

                      Ron B[ee]








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                    • cjamescook
                      ... Perhaps if the institution was really interested, LZOS would extend their autocollimation test setup as part of the price? Ask LZOS first, then the
                      Message 10 of 23 , Oct 22, 2003
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                        --- In tmboptical@yahoogroups.com, "tmboptical" <TMBoptical@a...>
                        wrote:

                        > Last week I had a phone conversation with Markus, and I asked
                        > what was the largest TMB apo LZOS could make. The reason was
                        > because an institution is interested in the largest apochromatic
                        > refractor that could be built. Markus said that the glass was
                        > not the limitation, but the focal length. This is because of
                        > the autocollimation test setup.

                        Perhaps if the institution was really interested, LZOS would extend
                        their autocollimation test setup as part of the price? Ask LZOS
                        first, then the institution?

                        Helpfully,
                        -Jim
                      • tomdemary
                        Sounds like a dream project! Congratulations. Seems like LZOS could roll up a railroad boxcar for a temporary, extended testbed. After testing, use the
                        Message 11 of 23 , Oct 22, 2003
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                          Sounds like a "dream" project! Congratulations.

                          Seems like LZOS could roll up a railroad boxcar for a
                          temporary, extended testbed. After testing, use the
                          boxcar to ship the lens. Simple and efficient?

                          Tom DeMary


                          --- In tmboptical@yahoogroups.com, "tmboptical" <TMBoptical@a...> wrote:
                          > --- In tmboptical@yahoogroups.com, "izar21093" <izar@j...> wrote:
                          > > Now,,, a 36" TMB APO..................................
                          > >
                          >
                          > Last week I had a phone conversation with Markus, and I asked
                          > what was the largest TMB apo LZOS could make. The reason was
                          > because an institution is interested in the largest apochromatic
                          > refractor that could be built. Markus said that the glass was
                          > not the limitation, but the focal length. This is because of
                          > the autocollimation test setup. So, it is really up to me to come
                          > up with a superior design, that would correct aberrations at a
                          > relatively fast focal ratio. So far I have a 24" design that
                          > would work. Not bad, but I don't think a 36" is in the cards. :-)
                          >
                          > Thomas Back
                        • Mike C
                          ... Judging by the size and scope of the autocollimator, I wonder if the monetary returns on a single gigantic lens, or even a batch of them, would even be of
                          Message 12 of 23 , Oct 22, 2003
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                            > Perhaps if the institution was really interested, LZOS would extend
                            > their autocollimation test setup as part of the price? Ask LZOS
                            > first, then the institution?
                            >
                            > Helpfully,
                            > -Jim

                            Judging by the size and scope of the autocollimator, I wonder if the monetary
                            returns on a single gigantic lens, or even a batch of them, would even be of interest
                            to LZOS if they had to modify the autocollimator.

                            LZOS autocollimator pics:
                            http://tinyurl.com/ry22
                            http://tinyurl.com/ry28

                            You can mentally combine those two images to see the scope of that bad boy.

                            Mike C
                          • glasspusher2001
                            No one every read about Alvan Clark & Sons limiting their lens size due to their autocollimator being too short. Otherwise we would not have one each of 36
                            Message 13 of 23 , Oct 22, 2003
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                              No one every read about Alvan Clark & Sons limiting their lens size
                              due to their autocollimator being too short.

                              Otherwise we would not have one each of 36" and 40" ;).

                              Clear skies

                              Don
                            • wjburg
                              Thomas, I believe I have read somewhere that in the 40 inch the glass actually deforms as the telescope is aimed upward. Is there a practical limit to the
                              Message 14 of 23 , Oct 22, 2003
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                                Thomas,

                                I believe I have read somewhere that in the 40 inch the glass
                                actually deforms as the telescope is aimed upward. Is there a
                                practical limit to the weight of each element of an objective that
                                will eventually limit how big a lens can be made? I realize this is
                                not quite in your expertise, but the LZOS people must have some idea
                                of limits.

                                bill

                                --- In tmboptical@yahoogroups.com, "tmboptical" <TMBoptical@a...>
                                wrote:
                                > --- In tmboptical@yahoogroups.com, "izar21093" <izar@j...> wrote:
                                > > Now,,, a 36" TMB APO..................................
                                >
                                > Last week I had a phone conversation with Markus, and I asked
                                > what was the largest TMB apo LZOS could make. The reason was
                                > because an institution is interested in the largest apochromatic
                                > refractor that could be built. Markus said that the glass was
                                > not the limitation, but the focal length. This is because of
                                > the autocollimation test setup. So, it is really up to me to come
                                > up with a superior design, that would correct aberrations at a
                                > relatively fast focal ratio. So far I have a 24" design that
                                > would work. Not bad, but I don't think a 36" is in the cards. :-)
                                >
                                > Thomas Back
                              • Savio Fong
                                I am not sure if Markus is referring me, of my queries for the price of a meter size APM reflector vs large aperture APO. I am applying a funding to build an
                                Message 15 of 23 , Oct 22, 2003
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                                  I am not sure if Markus is referring me, of my queries for the price of
                                  a meter size APM reflector vs large aperture APO.

                                  I am applying a funding to build an education-driven observatory, the
                                  maximun funding we can get will be less than one million $. In that
                                  case, I would say a large APO will be better than a reflector. As Hong
                                  Kong is very light polluted, so a high contrast APO would definitely
                                  perform better than a bigger reflector. And I guess for education use,
                                  the optimal focal length would be ~2000 to 3000mm (80 to 120 inches), to
                                  delivery a usable image scale for most popular objects.

                                  Markus told me the max focal length that can put onto the tester is
                                  ~3000mm (120 inches). Though a 24" F5 APO is not what we want.

                                  Savio Fong
                                  Hong Kong
                                  http://www.astro.org.hk

                                  cjamescook wrote:

                                  >--- In tmboptical@yahoogroups.com, "tmboptical" <TMBoptical@a...>
                                  >wrote:
                                  >
                                  >
                                  >
                                  >>Last week I had a phone conversation with Markus, and I asked
                                  >>what was the largest TMB apo LZOS could make. The reason was
                                  >>because an institution is interested in the largest apochromatic
                                  >>refractor that could be built. Markus said that the glass was
                                  >>not the limitation, but the focal length. This is because of
                                  >>the autocollimation test setup.
                                  >>
                                  >>
                                  >
                                  >Perhaps if the institution was really interested, LZOS would extend
                                  >their autocollimation test setup as part of the price? Ask LZOS
                                  >first, then the institution?
                                  >
                                  >Helpfully,
                                  >-Jim
                                  >
                                  >
                                  >
                                  >To unsubscribe from this group, send an email to:
                                  >tmboptical-unsubscribe@egroups.com
                                  >
                                  >
                                  >
                                  >Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
                                  >
                                  >
                                  >
                                  >



                                  [Non-text portions of this message have been removed]
                                • tmboptical
                                  ... Hi Mike, The 24 TMB triplet design is f/10. Thomas Back
                                  Message 16 of 23 , Oct 24, 2003
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                                    --- In tmboptical@yahoogroups.com, "Mike C" <mike@e...> wrote:
                                    > >
                                    > > Last week I had a phone conversation with Markus, and I asked
                                    > > what was the largest TMB apo LZOS could make. The reason was
                                    > > because an institution is interested in the largest apochromatic
                                    > > refractor that could be built. Markus said that the glass was
                                    > > not the limitation, but the focal length. This is because of
                                    > > the autocollimation test setup. So, it is really up to me to come
                                    > > up with a superior design, that would correct aberrations at a
                                    > > relatively fast focal ratio. So far I have a 24" design that
                                    > > would work. Not bad, but I don't think a 36" is in the cards. :-)
                                    > >
                                    > > Thomas Back
                                    >
                                    >
                                    > Wow! Curious Indeed... What focal ratio was the 24"?
                                    >
                                    > Mike

                                    Hi Mike,

                                    The 24" TMB triplet design is f/10.

                                    Thomas Back
                                  • tmboptical
                                    ... So would I! There is always Mars 2005. Thomas Back ...
                                    Message 17 of 23 , Oct 24, 2003
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                                      --- In tmboptical@yahoogroups.com, "Michael Downing" <michael@s...>
                                      wrote:
                                      > WOW!
                                      > I would love to have a session with that scope :-)
                                      >
                                      > Michael Downing
                                      > www.astroden.com <http://www.astroden.com/>

                                      So would I! There is always Mars 2005.

                                      Thomas Back

                                      >
                                      >
                                      > -----Original Message-----
                                      > From: ronbee77 [mailto:ronby@c...]
                                      > Sent: Tuesday, October 21, 2003 6:45 PM
                                      > To: tmboptical@yahoogroups.com
                                      > Subject: [tmboptical] Mars sketches from giant refractor - FYI
                                      >
                                      > http://mtham.ucolick.org/public/TwoWeeksOnMars/drawings/
                                      > Awesome, ain't it! And a nice writeup...
                                      > http://mtham.ucolick.org/public/TwoWeeksOnMars/writings/
                                      > Note how the 36-inch was stopped down to 20-inch to control the
                                      > chromatic aberrations.
                                      >
                                      > Ron B[ee]
                                      >
                                      >
                                      >
                                      >
                                      >
                                      >
                                      >
                                      >
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                                    • tmboptical
                                      ... Jim, Markus would know more, but I don t think it would be in LZOS best interests (investment wise) to expand their autocollimation test setup for a single
                                      Message 18 of 23 , Oct 24, 2003
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                                        --- In tmboptical@yahoogroups.com, "cjamescook" <jimcook@a...> wrote:
                                        > --- In tmboptical@yahoogroups.com, "tmboptical" <TMBoptical@a...>
                                        > wrote:
                                        >
                                        > > Last week I had a phone conversation with Markus, and I asked
                                        > > what was the largest TMB apo LZOS could make. The reason was
                                        > > because an institution is interested in the largest apochromatic
                                        > > refractor that could be built. Markus said that the glass was
                                        > > not the limitation, but the focal length. This is because of
                                        > > the autocollimation test setup.
                                        >
                                        > Perhaps if the institution was really interested, LZOS would extend
                                        > their autocollimation test setup as part of the price? Ask LZOS
                                        > first, then the institution?
                                        >
                                        > Helpfully,
                                        > -Jim

                                        Jim,

                                        Markus would know more, but I don't think it would be in LZOS best
                                        interests (investment wise) to expand their autocollimation test
                                        setup for a single project. They make most of their money doing
                                        fast, large (1-meter and above) reflective systems.

                                        Thomas Back
                                      • tmboptical
                                        ... Thanks Tom. It sure would be a proud achievement to have TMB design and sell the largest apochromatic refractor in the world. And it would allow me to
                                        Message 19 of 23 , Oct 24, 2003
                                        • 0 Attachment
                                          --- In tmboptical@yahoogroups.com, "tomdemary" <t.demary@e...> wrote:
                                          > Sounds like a "dream" project! Congratulations.
                                          >
                                          > Seems like LZOS could roll up a railroad boxcar for a
                                          > temporary, extended testbed. After testing, use the
                                          > boxcar to ship the lens. Simple and efficient?
                                          >
                                          > Tom DeMary

                                          Thanks Tom. It sure would be a proud achievement to have TMB design
                                          and sell the largest apochromatic refractor in the world. And it
                                          would allow me to invest into my company, and make it that much
                                          better (an interferometer, more large shop machinery, etc.)

                                          That sounds like a good idea. But alas, I don't think the railroad
                                          boxcar would be practical from a testing setup, unless it could be
                                          made to extreme tolerances, and have it super stable.

                                          Thomas Back
                                        • tmboptical
                                          ... extend ... the monetary ... even be of interest ... bad boy. ... Quite correct Mike. Thomas Back
                                          Message 20 of 23 , Oct 24, 2003
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                                            --- In tmboptical@yahoogroups.com, "Mike C" <mike@e...> wrote:
                                            >
                                            > > Perhaps if the institution was really interested, LZOS would
                                            extend
                                            > > their autocollimation test setup as part of the price? Ask LZOS
                                            > > first, then the institution?
                                            > >
                                            > > Helpfully,
                                            > > -Jim
                                            >
                                            > Judging by the size and scope of the autocollimator, I wonder if
                                            the monetary
                                            > returns on a single gigantic lens, or even a batch of them, would
                                            even be of interest
                                            > to LZOS if they had to modify the autocollimator.
                                            >
                                            > LZOS autocollimator pics:
                                            > http://tinyurl.com/ry22
                                            > http://tinyurl.com/ry28
                                            >
                                            > You can mentally combine those two images to see the scope of that
                                            bad boy.
                                            >
                                            > Mike C

                                            Quite correct Mike.

                                            Thomas Back
                                          • tmboptical
                                            ... Don, Yes, but that was different. The Clark s only made refractors, and was planning a 60 , until Hale nixed the idea in favor of the Mount Wilson 60 f/5.
                                            Message 21 of 23 , Oct 24, 2003
                                            • 0 Attachment
                                              --- In tmboptical@yahoogroups.com, "glasspusher2001"
                                              <glasspusher2001@y...> wrote:
                                              > No one every read about Alvan Clark & Sons limiting their lens size
                                              > due to their autocollimator being too short.
                                              >
                                              > Otherwise we would not have one each of 36" and 40" ;).
                                              >
                                              > Clear skies
                                              >
                                              > Don

                                              Don,

                                              Yes, but that was different. The Clark's only made refractors,
                                              and was planning a 60", until Hale nixed the idea in favor of
                                              the Mount Wilson 60" f/5. Alvan Clark even published an article
                                              about the future of larger (above 40-inches) achromatic refractors
                                              in an old issue of Popular Astronomy. The often heard 40" limit
                                              is just that, just talk. With today's optical glass, a 60" could
                                              be made, and with a sub-diameter chromatic corrector (not a
                                              chromacor corrector), designed like the one that Roland made for
                                              the Rockfort group's 10" achromat, this would be the ultimate
                                              planetary telescope.

                                              Thomas Back
                                            • tmboptical
                                              ... Hi Bill, As I said, I think deformation isn t a problem until you reach around 60 . There is an interesting effect about large deforming elements. They
                                              Message 22 of 23 , Oct 24, 2003
                                              • 0 Attachment
                                                --- In tmboptical@yahoogroups.com, "wjburg" <wjburg@y...> wrote:
                                                > Thomas,
                                                >
                                                > I believe I have read somewhere that in the 40 inch the glass
                                                > actually deforms as the telescope is aimed upward. Is there a
                                                > practical limit to the weight of each element of an objective that
                                                > will eventually limit how big a lens can be made? I realize this
                                                > is not quite in your expertise, but the LZOS people must have some
                                                > idea of limits.
                                                >
                                                > bill

                                                Hi Bill,

                                                As I said, I think deformation isn't a problem until you reach
                                                around 60". There is an interesting effect about large deforming
                                                elements. They tend to cancel out each others wavefront errors
                                                (this is only true with the standard crown/flint achromat), and
                                                with a proper cell, and having the lens figured at about a 40
                                                degree angle, this averages out where the telescope is most likely
                                                to be used the most at (the Clark's did this with the 40" during
                                                figuring), but by no means is 40" the limit. Just look at the
                                                large Schmidt cameras, their main BK-7 element is larger than 40".

                                                Thomas Back
                                              • tmboptical
                                                ... price of ... the ... Hong ... definitely ... use, ... inches), to ... First, it wasn t Markus, but an institution in the US, contacting TMB Optical about
                                                Message 23 of 23 , Oct 24, 2003
                                                • 0 Attachment
                                                  --- In tmboptical@yahoogroups.com, Savio Fong <saviofong@f...> wrote:
                                                  > I am not sure if Markus is referring me, of my queries for the
                                                  price of
                                                  > a meter size APM reflector vs large aperture APO.
                                                  >
                                                  > I am applying a funding to build an education-driven observatory,
                                                  the
                                                  > maximun funding we can get will be less than one million $. In that
                                                  > case, I would say a large APO will be better than a reflector. As
                                                  Hong
                                                  > Kong is very light polluted, so a high contrast APO would
                                                  definitely
                                                  > perform better than a bigger reflector. And I guess for education
                                                  use,
                                                  > the optimal focal length would be ~2000 to 3000mm (80 to 120
                                                  inches), to
                                                  > delivery a usable image scale for most popular objects.
                                                  >
                                                  > Markus told me the max focal length that can put onto the tester is
                                                  > ~3000mm (120 inches). Though a 24" F5 APO is not what we want.
                                                  >
                                                  > Savio Fong
                                                  > Hong Kong
                                                  > http://www.astro.org.hk

                                                  First, it wasn't Markus, but an institution in the US, contacting
                                                  TMB Optical about the largest apochromat that I could have made
                                                  for them. I'm not sure where you got your information from, or if
                                                  it was Markus, and in error, as the limit is not 120 inches --
                                                  our delivered TMB 14" f/13 has a focal length of 182".

                                                  Thomas Back
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