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Re: 27mm Panoptic vs. 34mm Siebert Observatory Series

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  • rapideye.geo
    ... Dale over at DBA carries them: http://www.dbaastronomy.com/GSO%20EP s.htm You may be able to find them a couple of dollars cheaper somewhere else, but Dale
    Message 1 of 9 , Mar 1 5:35 AM
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      --- In skyquest-telescopes@yahoogroups.com, "jrbcupertinopetaluma"
      <james.barnett@...> wrote:
      > Where can I find a GSO 30mm? :)

      Dale over at DBA carries them:
      http://www.dbaastronomy.com/GSO%20EP's.htm

      You may be able to find them a couple of dollars cheaper somewhere
      else, but Dale is tops in customer service and a really nice guy!!!

      Tell 'em I sent you!

      <RE>
    • jrbcupertinopetaluma
      ... Gene: I ll take a look and report back this eveing when I get home. Jim
      Message 2 of 9 , Mar 1 7:57 AM
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        --- In skyquest-telescopes@yahoogroups.com, "Gene Baraff"
        <g2baraff@...> wrote:
        >
        > --- In skyquest-telescopes@yahoogroups.com, "jrbcupertinopetaluma"
        > <james.barnett@> wrote:
        > >
        > > Hi all, as promised some time ago, I am posting a micro-review
        > > of the 2" 34mm Siebert Observatory Series eyepiece. I've
        > > decided to use the 2" 27mm Televue Panoptic, and eyepiece that
        > > more of you are probably familiar with than the Siebert, as a
        > > benchmark to illustrate some of the pros and cons of the Siebert
        > > in my 12XTi.
        > >
        > > ************
        > Point of information: what is the diameter of the field stops on the
        > two eyepieces you are comparing?
        >
        > Thanks.
        >
        > Gene
        >

        Gene:

        I'll take a look and report back this eveing when I get home.

        Jim
      • Jack Kramer
        From: Gene Baraff ... Gene, a few days ago I received a 27mm Panoptic -- the included spec sheet says the field stop is 30.5mm. Of
        Message 3 of 9 , Mar 1 9:16 AM
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          From: "Gene Baraff" <g2baraff@...>
          > Point of information: what is the diameter of the field stops on the
          > two eyepieces you are comparing?

          Gene, a few days ago I received a 27mm Panoptic -- the included spec sheet says the field stop is 30.5mm. Of course, it's been too cloudy to try it out.

          Jack Kramer
          Lily Lake, Illinois
          http://home.att.net/~jak.stargate/wsb/index.html
        • jrbcupertinopetaluma
          ... the ... Gene: The Panoptic s field stop looks to be just about 31mm and the Siebert s is about 38mm. Jim
          Message 4 of 9 , Mar 1 8:20 PM
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            --- In skyquest-telescopes@yahoogroups.com, "Gene Baraff"
            <g2baraff@...> wrote:
            >
            > --- In skyquest-telescopes@yahoogroups.com, "jrbcupertinopetaluma"
            > <james.barnett@> wrote:
            > >
            > > Hi all, as promised some time ago, I am posting a micro-review
            > > of the 2" 34mm Siebert Observatory Series eyepiece. I've
            > > decided to use the 2" 27mm Televue Panoptic, and eyepiece that
            > > more of you are probably familiar with than the Siebert, as a
            > > benchmark to illustrate some of the pros and cons of the Siebert
            > > in my 12XTi.
            > >
            > > ************
            > Point of information: what is the diameter of the field stops on
            the
            > two eyepieces you are comparing?
            >
            > Thanks.
            >
            > Gene
            >

            Gene:

            The Panoptic's field stop looks to be just about 31mm and the
            Siebert's is about 38mm.

            Jim
          • Jack Kramer
            From: jrbcupertinopetaluma ... That s an important point. Normally one would expect the eyepiece with the larger field stop to
            Message 5 of 9 , Mar 2 6:55 AM
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              From: "jrbcupertinopetaluma" <james.barnett@...>
              > The Panoptic's field stop looks to be just about 31mm and the
              > Siebert's is about 38mm.

              That's an important point. Normally one would expect the eyepiece with the larger field stop to have the poorer edge-of-field performance. But that appears not to be the case here, which suggests the Siebert is a pretty good eyepiece. This is especially true considering that coma is a common problem for wide-field eyepieces in fast Newtonians.

              I recently purchased a 27mm Panoptic, but due to cloudy skies (of course) have not had a chance to try it on my XT12i. It'll be interesting to see whether my experience is similar.

              Jack Kramer
              Lily Lake, Illinois
              http://home.att.net/~jak.stargate/wsb/index.html
            • jrbcupertinopetaluma
              ... with the larger field stop to have the poorer edge-of-field performance. But that appears not to be the case here, which suggests the Siebert is a pretty
              Message 6 of 9 , Mar 2 3:29 PM
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                --- In skyquest-telescopes@yahoogroups.com, "Jack Kramer"
                <jak.stargate@...> wrote:
                >
                > From: "jrbcupertinopetaluma" <james.barnett@...>
                > > The Panoptic's field stop looks to be just about 31mm and the
                > > Siebert's is about 38mm.
                >
                > That's an important point. Normally one would expect the eyepiece
                with the larger field stop to have the poorer edge-of-field
                performance. But that appears not to be the case here, which suggests
                the Siebert is a pretty good eyepiece. This is especially true
                considering that coma is a common problem for wide-field eyepieces in
                fast Newtonians.
                >
                > I recently purchased a 27mm Panoptic, but due to cloudy skies (of
                course) have not had a chance to try it on my XT12i. It'll be
                interesting to see whether my experience is similar.
                >
                > Jack Kramer
                > Lily Lake, Illinois
                > http://home.att.net/~jak.stargate/wsb/index.html
                >

                Hi Jack. Yep, I understood the gist of Gene's question, and was
                wondering whether the riddle might be solved by a vingnetting field
                stop in the Siebert, but that just wasn't the case.

                I am really looking forward to your report on your 27mm Panoptic in
                your XT12i. It's possible, though probably not likely, that mine has
                issues. Mine is new as well, and is made in Taiwan ROC. It's my
                first non-Japan Televue, but Al swears up and down that the QC in
                Taiwan is on par with the QC in Japan.

                To be clear, when I say my Panoptic shows "distortion" at the edge,
                what I mean is the inherent coma in the 12" f/5 optical system is
                apparent. The coma is much, much harder to spot in the Siebert
                amazingly. Still the throughput of the Panoptic on axis is astounding
                and I can tell already it's a gem for observing nebula.
              • Jack Kramer
                From: jrbcupertinopetaluma ... Jim, I had a chance to use the 27mm Panoptic for the first time tonight in the XT12i. Mine also
                Message 7 of 9 , Mar 4 7:35 PM
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                  From: "jrbcupertinopetaluma" <james.barnett@...>
                  > I am really looking forward to your report on your 27mm Panoptic in
                  > your XT12i. It's possible, though probably not likely, that mine has
                  > issues.

                  Jim, I had a chance to use the 27mm Panoptic for the first time tonight in the XT12i. Mine also betrayed a little softness at the edges -- I'd guess starting at about the outer 10% to 20% of the field. No doubt this was the typical effect of coma in a fast system. But like you said, the center of the field had great throughput and was very sharp.

                  Jack Kramer
                  Lily Lake, Illinois
                  http://home.att.net/~jak.stargate/wsb/index.html
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