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

Re: Can you see Pluto in a 4 inch scope?

Expand Messages
  • Derek Wong
    ... OK, I m here to be ridiculed. But before I get trashed too much, let me say that I saw Pluto with a Guide chart enhanced with USNO A 2.0 data. The
    Message 1 of 8 , Jun 1 1:14 AM
      > I believe Derek _thinks_ he saw Pluto. Sometimes I wonder: when
      > people spend ~$2500 on a 92mm scope (assuming he bought new, and
      > didn't pay the crazy premiums these scopes are going for used), how
      > much the desire to rationalize the purchase contributes to the well
      > known effect of "averted imagination."

      OK, I'm here to be ridiculed. But before I get trashed too much, let
      me say that I saw Pluto with a Guide chart enhanced with USNO A 2.0
      data. The observation was made well away from the scope field, at
      150x by using hyperventilation to fight the effects of high altitude
      and covering my eye until the staring into the eyepiece. Pluto was
      visible about 30% of the time, and this observation was over at least
      twenty minutes after I found the field.

      I confirmed the observation with the 7" Teleport the next night. I
      had trouble in a brief glance in the 14.5" because there were too
      many
      stars, and in the 18" must have been a pain. Also, I am nowhere near
      the observer that some people like Jay Freeman, etc. are.

      Please see the following:

      1. Todd Gross' webpage www.weatherman.com under 60 scope reviews,
      #58
      which is the Tak 76. Todd suspects the 13th mag star near M57 with
      this scope. I actually think this star is a lot brighter than mag 13
      (don't believe the GSC, as these values can be way off). But I
      believe Todd observes in quite a bit of light pollution.

      2. I can't access the deja archives. However, Jeff Medkeff, an S+T
      contributor saw 14.5 or thereabouts with a 4.5" reflector. Jeff had
      50% more light gathering power but saw a star over twice as dim as
      Pluto. Is Jeff lying? Well, it's too bad the storm over that
      observation is unavailable, but the thread went on quite awhile.

      3. Contact Brian Skiff the professional astronomer and extremely
      well
      respected observer. He saw Pluto with a PRONTO, in darker mag 7
      conditions. Yes folks, a 70mm semi-apo. Do you think he is
      imagining
      things?

      4. Don Pensack, one of my mentors and with 30 years observing
      experience saw mag 15.9 small galaxies with his 8" SCT. Again, do
      the
      math.

      5. See the Observer's Page, S+T April 1994 P. 106-108 by Roger Clark.

      This gives an estimate of limiting magnitude in percentages. Here is
      some info for 3-4" scopes:

      98% 90% 50% 20% 10% 5% 2%
      3" 12.1 12.6 13.1 13.6 14.1 14.8 15.6
      4" 12.7 13.2 13.7 14.2 14.7 15.4 16.2

      If we interpolate, then you can see that the a 3.64" scope is right
      between the 20%-50% level of detection. And no, I didn't review this
      diagram before.

      Someone commented on Stephen O'Meara. Well, his observations as well
      as Barbara Wilson's are on the order of the 2% level, ie. mag 15.6
      with a 3" scope. The same article above says that O'Meara saw
      Halley's comet at 19 mag with a 20.4 mag field star with a 24", which
      is equivalent to mag 17 with a 6" (at the 2% limit of the chart).
      This is in a completely different league.

      OK, now about spending a ridiculous amount for a 92mm scope--yes, it
      is expensive, but I didn't pay as much as for a Questar. I am under
      no illusions about the limitations of aperture. The sharp refractive
      objects do give it some advantage over other kinds of scopes of
      3.5-4.5" aperture, but the 7" Teleport trashed it on DSO's (and would
      on planets also).

      I would advise everyone to at least test their abilities by trying
      all
      of Jay Freeman's techniques on the TAC webpage, listening to Jeff
      Medkeff's limiting magnitude talk, then observing with experienced
      people and trying crazy things yourself. You will be amazed. I have
      a long way to go, as Jeff, Jay, etc. are at least a half magnitude
      deeper than I.

      When I observed Himalia with my 12.5" I was careful to get a
      confirmation from a gentleman named Czernic Crute. Next time I will
      try to get someone to confirm an observation such as this, but most
      people don't want to spend a half hour with an eye patch over one eye
      just to get a few averted vision glimpses of some dim point.

      By the way, my next bit of fabrication will be to try to observe
      Pluto
      with a 10" from my house with limiting mag 4-4.5. I already imagined
      that I did it with my 12.5", who knows what I can dream about now?

      Happy averted imagination,

      Derek
    • amanguy61@hotmail.com
      ... altitude ... least ... Hi Derek, Thanks for the info on observing tricks, not intended but useful for me (I have only about 9 months in this hobby). Also
      Message 2 of 8 , Jun 1 9:58 AM
        > me say that I saw Pluto with a Guide chart enhanced with USNO A 2.0
        > data. The observation was made well away from the scope field, at
        > 150x by using hyperventilation to fight the effects of high
        altitude
        > and covering my eye until the staring into the eyepiece. Pluto was
        > visible about 30% of the time, and this observation was over at
        least
        > twenty minutes after I found the field.

        Hi Derek,

        Thanks for the info on observing tricks, not intended but useful for
        me (I have only about 9 months in this hobby). Also for the info
        about the importance of good seeing, dark location, good eyes, and
        potential of small telescopes.

        Impresive equipment you have!
        I own a cheap 6" reflector and a TV Ranger that I use most for nature
        study.
        If I stay in the hobby I might go for a good scope. Any suggestions?,
        I am more of a DSO guy. How is that 7" Teleport? any problems?

        Is that 92mm a AP Stowaway? if it is, you have a dreamscope! lucky...

        Thanks again, and clear skies,
        Chiang Ma
      • Derek Wong
        ... Hi Chiang: The Stowaway is a great small scope, but if that 6 has any figure at all it will kill the Stowaway on DSO s. The Teleport IS a dream airline
        Message 3 of 8 , Jun 1 8:34 PM
          --- Chiang Ma wrote:

          > Impresive equipment you have!
          > I own a cheap 6" reflector and a TV Ranger that I use most
          > for nature study.

          > I am more of a DSO guy. How is that 7" Teleport? any problems?
          >
          > Is that 92mm a AP Stowaway? if it is, you have a dreamscope!


          Hi Chiang:

          The Stowaway is a great small scope, but if that 6" has any figure at
          all it will kill the Stowaway on DSO's.

          The Teleport IS a dream airline portable scope. The mirror got
          shaken
          up during transport and needed to be recollimated, but otherwise
          everything was OK. The optics were VERY nice. I'm little more than
          a
          beginner at the star test but this was one of the best I've seen.
          The
          mechanics are good. You would need a stool or flexible legs to
          observe comfortably. By the way, I just heard on s.a.a. about one
          disadvantage of the 10" version--they are easy to steal, and Tom's
          show scope was stolen :-(

          However, if you are a DSO person and can handle a big scope, for
          $2300
          I would keep the Ranger, sell the 6" and buy a 12.5" or 15" f/5
          Discovery scope. That would get you some awesome views of many
          DSO's,
          not to mention the planets.

          Derek
        • Matt Tarlach
          ... Derek- Glad you re here to defend yourself! Sorry if you took my posts as a slam...I thought my first reply was too heavy handed, which is why I came back
          Message 4 of 8 , Jun 2 8:52 AM
            --- In telescopes@egroups.com, "Derek Wong" <dawong@e...> wrote:
            >
            > OK, I'm here to be ridiculed. But before I get trashed too much...


            Derek-

            Glad you're here to defend yourself! Sorry if you took my posts as a
            slam...I thought my first reply was too heavy handed, which is why I
            came back a second time to make clear I didn't think you were
            fabricating, at least not consciously. At worst, I thought you might
            be guilty of a little self-deception, to which I have fallen prey
            often enough myself.

            All your references from some very credible and experienced people
            suggest that I am probably too closed-minded on this subject. I
            based my skepticism on my own experience (I'd call myself
            an "intermediate" observer) in hunting faint planetaries and galaxies
            in my 12.5." Perhaps this experience is not directly applicable to
            the detection of stellar objects in a smaller aperture. There is
            also the possibility that you and the other folks cited may be
            (gasp!) much better observers than me.

            As for the cost of the Stowaway, relative to the Questar, I don't
            think that's the way to show value! :-)

            Anyway, hope there are no hard feelings, as no slam was intended. If
            you did see Pluto, then congratulations! Despite all the citations,
            forgive this poor narrow-minded soul who cannot let go of his
            skepticism, and wants to say: "Show me!" Though of course in these
            kinds of cases that's impossible. I guess imagers don't have these
            kinds of arguments!

            Good luck with your future challenges!

            - Matt
          • amanguy61@hotmail.com
            ... Yes, I can handle a big scope. I was looking at the Starmaster 12.5 EL. Do you know how this one considering that it has a Zambuto mirror compares to a
            Message 5 of 8 , Jun 2 11:17 AM
              > However, if you are a DSO person and can handle a big scope, for
              > $2300
              > I would keep the Ranger, sell the 6" and buy a 12.5" or 15" f/5
              > Discovery scope. That would get you some awesome views of many
              > DSO's,
              > not to mention the planets.
              > Derek

              Yes, I can handle a big scope.
              I was looking at the Starmaster 12.5" EL. Do you know how this one
              considering that it has a Zambuto mirror compares to a 12.5"/15"
              Discovery? I mean in optical performance for DSO's. Will a Z mirror
              make a big difference? (in price it makes a big difference).

              I ordered a 10" Discovery ($569) 2 months ago with a delivery
              time of 45 days; I have not received it and for the posts I have read
              about their inconsistent delivery times I am not expecting to receive
              it in a very close future, if I ever receive it. I might just cancel
              the order.
              I ordered it just to see how big of a difference it is vs my 6" and
              probably jump later to a better quality/bigger scope. Also I just
              received the Obsession video and I am impressed (obsessed?).

              About selling my 6", well... that is my first scope and I love it. It
              is strange that depending on my mood I use the ranger, the 6", or
              just the binos; maybe I am the type that needs a bunch of different
              scopes :-)

              Thanks in advance for any input,
              Chiang
            • Derek Wong
              ... I have seen but never used the Discovery trusses, so I will speak in general terms. When you get a premium Dob like a Starmaster, there are some very nice
              Message 6 of 8 , Jun 2 12:27 PM
                --- In telescopes@egroups.com, amanguy61@h... wrote:

                > Yes, I can handle a big scope.
                > I was looking at the Starmaster 12.5" EL. Do you know how this one
                > considering that it has a Zambuto mirror compares to a 12.5"/15"
                > Discovery? I mean in optical performance for DSO's. Will a Z mirror
                > make a big difference? (in price it makes a big difference).

                I have seen but never used the Discovery trusses, so I will speak in
                general terms.

                When you get a premium Dob like a Starmaster, there are some very
                nice
                features:

                --The mirror cell is a work of art, and supports the primary in a
                fashion that prevents stresses at different angles.

                --The fit and precision is excellent. The collimation will not vary
                much if you tip the scope, very important with fast dobs.

                --Thin mirrors 1.6" aid cooling

                --You can order a Feathertouch focuser, which makes observing a joy.

                --Service is excellent. Rick and Carol get calls on Saturdays at
                7PM,
                and are more than happy to answer questions.

                In these scopes, mechanical precision is at least as important, if
                not
                more important as the mirror figure (assuming the mirror isn't a real
                dog). You may have a great mirror, but if the scope sags a couple
                millimeters, the mirror is not supported well or the scope has a long
                cooldown then you will not be diffaction limited even in the center
                of
                the mirror.

                On DSO's, a scope which is superior optically and/or mechanically
                will
                show a better view on all objects, especially globulars, dust lanes
                in
                galaxies, detail in planetaries, etc. Also, when after you see
                Jupiter you won't want to confine yourself to DSO's :-)

                > I ordered it just to see how big of a difference it is vs my 6" and
                > probably jump later to a better quality/bigger scope. Also I just
                > received the Obsession video and I am impressed (obsessed?).

                Forget about an intermediate scope, get the one you really want.
                Obsession also makes wonderful scopes. There is a big debate, but
                what sold me on the Starmaster was the GOTO/tracking system.

                > About selling my 6", well... that is my first scope and I love it.
                It
                > is strange that depending on my mood I use the ranger, the 6", or
                > just the binos; maybe I am the type that needs a bunch of different
                > scopes :-)

                Talk to Todd Gross :-)

                Derek
              Your message has been successfully submitted and would be delivered to recipients shortly.