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Re: [William-Optics] Re: Edge performance of the WO 80mm Fluorite

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  • Jose Rola
    I never saw it used for any other type, but i am not an expert clear skies Jose Rola ... From: gary To:
    Message 1 of 15 , Dec 1, 2004
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      I never saw it used for any other type, but i am not an expert

      clear skies
      Jose Rola

      ----- Original Message -----
      From: "gary" <yahoogroups@...>
      To: <William-Optics@yahoogroups.com>
      Sent: Wednesday, December 01, 2004 3:46 AM
      Subject: Re: [William-Optics] Re: Edge performance of the WO 80mm Fluorite


      >
      > Then a field flattener is only used in prime photography?
      >
      >
      > Jose Rola wrote:
      >>
      >> From: "gary"
      >>
      >>
      >>>I'm going to plead major ignorance on the subject of field flatteners,
      >>>which I always thought was a way to get a wider image (as they are also
      >>>called focal reducers).
      >>
      >>
      >> Hi,
      >>
      >> Field flattner and focal reducer are to diferent concepts, that sometimes
      >> are acheived with only one device, and in that case, it is called a
      >> reducer/flattener.
      >>
      >> Usually a telescope gives you a focused imagem that it is not a flat
      >> surface, but a spherical section, which is ok for your eye but not for a
      >> film or ccd, because they are flat. That's why you see defocused stars at
      >> the corners os the image, although they are focused at the center.
      >>
      >> There are two solutions that I konw about for this problem:
      >>
      >> a) one used in the Schmidt cameras, that was to put the film over a
      >> spherical surface, and soo the film plane will be shperical
      >>
      >> b) get a corrective lens so the image will be focused over a flat
      >> surface.
      >>
      >> Most of the times, the companies make a flattner that is also a focal
      >> reducer (Televue, TMB, ...), but there are flattners that do not change
      >> the
      >> focal length (Astrophysics,...) and even one that i know about that
      >> incresaes the focal length, like a barlow (Baader).
      >>
      >> clear skies
      >> Jose Rola
      >>
      >>
      >>
      >>
      >>
      >> Yahoo! Groups Links
      >>
      >>
      >>
      >>
      >>
      >>
      >>
      >>
      >>
      >
      >
      >
      >
      >
      > Yahoo! Groups Links
      >
      >
      >
      >
      >
      >
      >
      >
    • Jose Rola
      UAU, great finding Kurt!!! Thanks, now let s try to find Daniel! Clear skies Jose Rola ... From: kurt_friedrich To:
      Message 2 of 15 , Dec 1, 2004
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        UAU, great finding Kurt!!!

        Thanks, now let's try to find Daniel!

        Clear skies
        Jose Rola

        ----- Original Message -----
        From: "kurt_friedrich" <kurt_friedrich@...>
        To: <William-Optics@yahoogroups.com>
        Sent: Wednesday, December 01, 2004 5:22 AM
        Subject: [William-Optics] Re: Edge performance of the WO 80mm Fluorite


        >
        >
        > dah .... (on me) should have searched the old messages; there is
        > already a good report on the TV flattener, see:
        >
        > http://groups.yahoo.com/group/William-Optics/message/1774
        >
        > I would love to get an update from Daniel Johnson?
        >
        > Kurt
        >
        > --- In William-Optics@yahoogroups.com, "kurt_friedrich"
        > <kurt_friedrich@y...> wrote:
        >>
        >> I notice at this web site:
        >>
        >> http://www.telescopehouse.co.uk/page.aspx?
        >> f=on&theLang=001lngdef&pointerID=59024xfaiqRDY8AedOGEYs7CF5zA1pHa
        >>
        >> where they offer the Televue TRF 2008 Reducer/Flattener with these
        >> words:
        >>
        >> "Model TRF-2008 0.8X Reducer/Flattener converts TV-85 to 480mm
        > f/5.6
        >> and Pronto to 380mm f/5.4 for flat field, fast photography. Fully
        >> multi-coated 3-element unit inserts directly into 2" focuser,
        >> accepts standard T-rings for 35mm cameras. Also it can be used
        > with
        >> any 400-600mm refractor including TMB, Williams Optics and Orion
        > US."
        >>
        >> that looks pretty promising, anybody tried this?
        >> Kurt
        >>
        >>
        >> --- In William-Optics@yahoogroups.com, "kurt_friedrich"
        >> <kurt_friedrich@y...> wrote:
        >> >
        >> > I got mine Friday, and while there was a full moon last night, I
        >> was
        >> > able to get out and get some pictures. I did the double cluster,
        >> > some moon shots, M31 (just to see how it fits, too much moon for
        > a
        >> > good shot) and M39. I picked M39 as it was as far away from the
        >> moon
        >> > as I could get (without trees in the view).
        >> >
        >> > My conclusion is, if you want to use the full frame, this scope
        >> > needs a field flatener. If you want to see what I am talking
        >> about;
        >> > go to this web site: (ignore all the car stuff, note the very
        >> large
        >> > sentence "Analysis of edge performance of a WO 80mm Fluorite
        >> > triplet" at the very top, before the first car pic. Click on
        > that
        >> > and it will take you to 4 pics where you can see that the
        > corners
        >> of
        >> > the pictures taken at prime with a Canon 10d do not come out to
        >> > great.)
        >> >
        >> > http://www.angelfire.com/id/kurtfriedrich/
        >> >
        >> > The good news is, the scope has such a wide field, you can get
        >> large
        >> > objects that fall far from these corners, so a little cropping
        > and
        >> > all is well. I saw a thread about Williams promising a
        >> reducer ...
        >> > if there is such a beast coming, I hope it flatens too ... but I
        >> > think that might be next to impossible. I know Roland offers
        >> both
        >> > for the APs, but not both in one.
        >> >
        >> > Also, this was my first night with a new mount, the Celestron AS-
        >> GT.
        >> > It is plenty of mount for this light WA and my camera. Can't
        > wait
        >> > till the moon is gone and I can get serious with these.
        >> >
        >> > (Pic of scope in action)
        >> > http://tinyurl.com/6y4bx
        >> >
        >> > Kurt
        >
        >
        >
        >
        >
        >
        >
        > Yahoo! Groups Links
        >
        >
        >
        >
        >
        >
        >
        >
      • kurt_friedrich
        I checked Astromart to see if any sold there in the last 2 years. There were 4. THREE of them said they had never taken it out of the box! I guess its
        Message 3 of 15 , Dec 2, 2004
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          I checked Astromart to see if any sold there in the last 2 years.
          There were 4. THREE of them said they had never taken it out of the
          box! I guess its possible that some clever salesperson talked them
          into these as "required accessories"? I sent mail to the the one
          that didn't say it had never been use, and asked for their opinion
          about it.

          Kurt

          --- In William-Optics@yahoogroups.com, "Jose Rola" <jose.rola@c...>
          wrote:
          > UAU, great finding Kurt!!!
          >
          > Thanks, now let's try to find Daniel!
          >
          > Clear skies
          > Jose Rola
          >
          > ----- Original Message -----
          > From: "kurt_friedrich" <kurt_friedrich@y...>
          > To: <William-Optics@yahoogroups.com>
          > Sent: Wednesday, December 01, 2004 5:22 AM
          > Subject: [William-Optics] Re: Edge performance of the WO 80mm
          Fluorite
          >
          >
          > >
          > >
          > > dah .... (on me) should have searched the old messages; there is
          > > already a good report on the TV flattener, see:
          > >
          > > http://groups.yahoo.com/group/William-Optics/message/1774
          > >
          > > I would love to get an update from Daniel Johnson?
          > >
          > > Kurt
          > >
          > > --- In William-Optics@yahoogroups.com, "kurt_friedrich"
          > > <kurt_friedrich@y...> wrote:
          > >>
          > >> I notice at this web site:
          > >>
          > >> http://www.telescopehouse.co.uk/page.aspx?
          > >>
          f=on&theLang=001lngdef&pointerID=59024xfaiqRDY8AedOGEYs7CF5zA1pHa
          > >>
          > >> where they offer the Televue TRF 2008 Reducer/Flattener with
          these
          > >> words:
          > >>
          > >> "Model TRF-2008 0.8X Reducer/Flattener converts TV-85 to 480mm
          > > f/5.6
          > >> and Pronto to 380mm f/5.4 for flat field, fast photography.
          Fully
          > >> multi-coated 3-element unit inserts directly into 2" focuser,
          > >> accepts standard T-rings for 35mm cameras. Also it can be used
          > > with
          > >> any 400-600mm refractor including TMB, Williams Optics and
          Orion
          > > US."
          > >>
          > >> that looks pretty promising, anybody tried this?
          > >> Kurt
          > >>
          > >>
          > >> --- In William-Optics@yahoogroups.com, "kurt_friedrich"
          > >> <kurt_friedrich@y...> wrote:
          > >> >
          > >> > I got mine Friday, and while there was a full moon last
          night, I
          > >> was
          > >> > able to get out and get some pictures. I did the double
          cluster,
          > >> > some moon shots, M31 (just to see how it fits, too much moon
          for
          > > a
          > >> > good shot) and M39. I picked M39 as it was as far away from
          the
          > >> moon
          > >> > as I could get (without trees in the view).
          > >> >
          > >> > My conclusion is, if you want to use the full frame, this
          scope
          > >> > needs a field flatener. If you want to see what I am talking
          > >> about;
          > >> > go to this web site: (ignore all the car stuff, note the very
          > >> large
          > >> > sentence "Analysis of edge performance of a WO 80mm Fluorite
          > >> > triplet" at the very top, before the first car pic. Click on
          > > that
          > >> > and it will take you to 4 pics where you can see that the
          > > corners
          > >> of
          > >> > the pictures taken at prime with a Canon 10d do not come out
          to
          > >> > great.)
          > >> >
          > >> > http://www.angelfire.com/id/kurtfriedrich/
          > >> >
          > >> > The good news is, the scope has such a wide field, you can
          get
          > >> large
          > >> > objects that fall far from these corners, so a little
          cropping
          > > and
          > >> > all is well. I saw a thread about Williams promising a
          > >> reducer ...
          > >> > if there is such a beast coming, I hope it flatens too ...
          but I
          > >> > think that might be next to impossible. I know Roland offers
          > >> both
          > >> > for the APs, but not both in one.
          > >> >
          > >> > Also, this was my first night with a new mount, the Celestron
          AS-
          > >> GT.
          > >> > It is plenty of mount for this light WA and my camera. Can't
          > > wait
          > >> > till the moon is gone and I can get serious with these.
          > >> >
          > >> > (Pic of scope in action)
          > >> > http://tinyurl.com/6y4bx
          > >> >
          > >> > Kurt
          > >
          > >
          > >
          > >
          > >
          > >
          > >
          > > Yahoo! Groups Links
          > >
          > >
          > >
          > >
          > >
          > >
          > >
          > >
        • kurt_friedrich
          I sent mail to the 2 who were not marked sold (there were like 1 year old ads) and they were both nice enough to reply that they had in fact sold. The one that
          Message 4 of 15 , Dec 3, 2004
          • 0 Attachment
            I sent mail to the 2 who were not marked sold (there were like 1
            year old ads) and they were both nice enough to reply that they had
            in fact sold. The one that had used it had sold his tv85 and moved
            up to a tv101, which has one built in.

            Kurt
            --- In William-Optics@yahoogroups.com, "kurt_friedrich"
            <kurt_friedrich@y...> wrote:
            >
            > I checked Astromart to see if any sold there in the last 2 years.
            > There were 4. THREE of them said they had never taken it out of
            the
            > box! I guess its possible that some clever salesperson talked
            them
            > into these as "required accessories"? I sent mail to the the one
            > that didn't say it had never been use, and asked for their opinion
            > about it.
            >
            > Kurt
            >
            > --- In William-Optics@yahoogroups.com, "Jose Rola"
            <jose.rola@c...>
            > wrote:
            > > UAU, great finding Kurt!!!
            > >
            > > Thanks, now let's try to find Daniel!
            > >
            > > Clear skies
            > > Jose Rola
            > >
            > > ----- Original Message -----
            > > From: "kurt_friedrich" <kurt_friedrich@y...>
            > > To: <William-Optics@yahoogroups.com>
            > > Sent: Wednesday, December 01, 2004 5:22 AM
            > > Subject: [William-Optics] Re: Edge performance of the WO 80mm
            > Fluorite
            > >
            > >
            > > >
            > > >
            > > > dah .... (on me) should have searched the old messages; there
            is
            > > > already a good report on the TV flattener, see:
            > > >
            > > > http://groups.yahoo.com/group/William-Optics/message/1774
            > > >
            > > > I would love to get an update from Daniel Johnson?
            > > >
            > > > Kurt
            > > >
            > > > --- In William-Optics@yahoogroups.com, "kurt_friedrich"
            > > > <kurt_friedrich@y...> wrote:
            > > >>
            > > >> I notice at this web site:
            > > >>
            > > >> http://www.telescopehouse.co.uk/page.aspx?
            > > >>
            > f=on&theLang=001lngdef&pointerID=59024xfaiqRDY8AedOGEYs7CF5zA1pHa
            > > >>
            > > >> where they offer the Televue TRF 2008 Reducer/Flattener with
            > these
            > > >> words:
            > > >>
            > > >> "Model TRF-2008 0.8X Reducer/Flattener converts TV-85 to
            480mm
            > > > f/5.6
            > > >> and Pronto to 380mm f/5.4 for flat field, fast photography.
            > Fully
            > > >> multi-coated 3-element unit inserts directly into 2" focuser,
            > > >> accepts standard T-rings for 35mm cameras. Also it can be
            used
            > > > with
            > > >> any 400-600mm refractor including TMB, Williams Optics and
            > Orion
            > > > US."
            > > >>
            > > >> that looks pretty promising, anybody tried this?
            > > >> Kurt
            > > >>
            > > >>
            > > >> --- In William-Optics@yahoogroups.com, "kurt_friedrich"
            > > >> <kurt_friedrich@y...> wrote:
            > > >> >
            > > >> > I got mine Friday, and while there was a full moon last
            > night, I
            > > >> was
            > > >> > able to get out and get some pictures. I did the double
            > cluster,
            > > >> > some moon shots, M31 (just to see how it fits, too much
            moon
            > for
            > > > a
            > > >> > good shot) and M39. I picked M39 as it was as far away from
            > the
            > > >> moon
            > > >> > as I could get (without trees in the view).
            > > >> >
            > > >> > My conclusion is, if you want to use the full frame, this
            > scope
            > > >> > needs a field flatener. If you want to see what I am
            talking
            > > >> about;
            > > >> > go to this web site: (ignore all the car stuff, note the
            very
            > > >> large
            > > >> > sentence "Analysis of edge performance of a WO 80mm
            Fluorite
            > > >> > triplet" at the very top, before the first car pic. Click
            on
            > > > that
            > > >> > and it will take you to 4 pics where you can see that the
            > > > corners
            > > >> of
            > > >> > the pictures taken at prime with a Canon 10d do not come
            out
            > to
            > > >> > great.)
            > > >> >
            > > >> > http://www.angelfire.com/id/kurtfriedrich/
            > > >> >
            > > >> > The good news is, the scope has such a wide field, you can
            > get
            > > >> large
            > > >> > objects that fall far from these corners, so a little
            > cropping
            > > > and
            > > >> > all is well. I saw a thread about Williams promising a
            > > >> reducer ...
            > > >> > if there is such a beast coming, I hope it flatens too ...
            > but I
            > > >> > think that might be next to impossible. I know Roland
            offers
            > > >> both
            > > >> > for the APs, but not both in one.
            > > >> >
            > > >> > Also, this was my first night with a new mount, the
            Celestron
            > AS-
            > > >> GT.
            > > >> > It is plenty of mount for this light WA and my camera.
            Can't
            > > > wait
            > > >> > till the moon is gone and I can get serious with these.
            > > >> >
            > > >> > (Pic of scope in action)
            > > >> > http://tinyurl.com/6y4bx
            > > >> >
            > > >> > Kurt
            > > >
            > > >
            > > >
            > > >
            > > >
            > > >
            > > >
            > > > Yahoo! Groups Links
            > > >
            > > >
            > > >
            > > >
            > > >
            > > >
            > > >
            > > >
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