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Electric focusers and dew shields

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  • kb9ilt
    Hi, I have a Meade 2080(8 inch SCT)and am thinking about adding an electric focuser and a dew shield. Before doing so, I m wondering what good or bad
    Message 1 of 3 , Mar 1 9:49 AM
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      Hi,

      I have a Meade 2080(8 inch SCT)and am thinking about adding an
      electric focuser and a dew shield. Before doing so, I'm wondering
      what good or bad experiences others have had with these two
      accessories.

      I see that both Meade and JMI make electric focusers that will work
      with my scope, but I wonder if one is better than the other. Any
      comments on these two products? Do they really focus without any
      shaking of the scope? Is the Meade worth the extra money?

      The dew shield by Meade is very expensive. I can't imagine that it
      could be worth the added expense over competing shields other that it
      matches the scope in color. I live in a rather light polluted area
      and have heard that a dew shield will improve the performance of an
      SCT by blocking out some of the nearby stray light. Has anyone
      noticed that this is true to any significant exent?

      Thanks,

      Paul
    • Adam Stuart
      Hi Paul: I am a newbie with a 10 LX200 but I will give you my opinion for what it is worth: I bought the MEADE electric focuser thinking all-MEADE equipment
      Message 2 of 3 , Mar 1 10:52 AM
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        Hi Paul:

        I am a newbie with a 10" LX200 but I will give you my
        opinion for what it is worth:

        I bought the MEADE electric focuser thinking all-MEADE
        equipment would be best for a newcomer. (I felt
        safer). The electric focuser has two speeds controlled
        by the hand paddle for focusing, and rough focusing
        can still be achieved with the focus knob (it is not
        fully disabled by installing the MEADE focuser). The
        drawback: image shift in the ep as you use the
        focuser. Your mileage may vary, but a typical image in
        my ep danced all over the FOV. For astrophotography or
        during focusing with a videocamera, the shift was
        quite a pain. I upgraded to a JMI NGF-S, which leaves
        the focus knob intact on the scope for rough focus and
        fine-focus is achieved by moving the ep drawtube. As a
        result, the scope mirror remains stationary, as does
        the image. The MEADE dew shield
        -is- pretty and expensive. I bought this also and it
        works as advertised. So would a piece of foam, I
        suppose, attached at the corrector plate end, or stiff
        cardboard...you get the picture. I have seen less
        expensive machined dew shields, and I am sure others
        will chime in with other brand names. Two other
        drawbacks to MEADE's shield is that the OTA cover
        doesn't fit over the end of the dew shield, and a
        Hartman Mask that is store-bought (another waste of
        money, but it looks nice) also doesn't fit over the
        shield.

        Good luck! Spend your money wisely.

        ADAM
        --- kb9ilt <kb9ilt@...> wrote:
        > Hi,
        >
        > I have a Meade 2080(8 inch SCT)and am thinking about
        > adding an
        > electric focuser and a dew shield. Before doing so,
        > I'm wondering
        > what good or bad experiences others have had with
        > these two
        > accessories.
        >
        > I see that both Meade and JMI make electric focusers
        > that will work
        > with my scope, but I wonder if one is better than
        > the other. Any
        > comments on these two products? Do they really focus
        > without any
        > shaking of the scope? Is the Meade worth the extra
        > money?
        >
        > The dew shield by Meade is very expensive. I can't
        > imagine that it
        > could be worth the added expense over competing
        > shields other that it
        > matches the scope in color. I live in a rather
        > light polluted area
        > and have heard that a dew shield will improve the
        > performance of an
        > SCT by blocking out some of the nearby stray light.
        > Has anyone
        > noticed that this is true to any significant exent?
        >
        > Thanks,
        >
        > Paul
        >
        >
        >


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      • rckrchrdsn
        I used the Meade 1206 focuser. I was aware of the differences between the styles before I purchased. Just to make it clear, the Meade focuser uses the knob
        Message 3 of 3 , Mar 5 9:05 AM
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          I used the Meade 1206 focuser. I was aware of the differences
          between the styles before I purchased. Just to make it clear, the
          Meade focuser uses the knob you would use and thus moves the mirror.
          The JMI adds a focuser to the optical train and moves the EP. You
          have to use both focusing methods with the latter.

          So with the JMI focuser, you move the mirror until you are close,
          center the image, and then you switch to the JMI and move the EP.
          With the Meade you move the mirror until you are slightly outfocus
          (so small adjustments are counterclockwise for the 10"), you switch
          to the slower speed, center the image, and focus with a
          counterclockwise movement. With this I get a centered image and well
          focused.

          The advantages of the meade are:
          1. less length in the optical train.
          2. less cost.
          3. less setup time.

          Many talk about the Digital Readout, but remember there is no
          temperature or mirror position compenstation. So the counter is
          approximate, but useful. I know the approximate positions under the
          Meade, so I am not sure if it is worth that much more. Having
          watched a good friend use it (read "with me over his shoulder making
          all sorts of useful[?] comments), he still had to make the
          timeconsuming final adjustments in the computer screen.

          Now that I have used the Meade for awhile, I am still thinking about
          changing. The performance of the ROBOFOCUS is seemingly worth the
          $375. It has temperture compensation and can be used with some nifty
          focusing software. We'll see. Others have fallen for the Van Slyke M
          Monster focuser, talking about "Light leaks with the JMI".

          I think much of this founded on personal bent. I would suggest
          purchasing the Meade on Astromart for $100 or so. (Wanted ads work
          very well.) Get used to moving the mirror for the focus, which is
          afterall THE focusing system for an SCT. Learn the methods for your
          scope to minimize image shift (moving the mirror through the full
          range periodically, counterclockwise motion for final focusing), then
          if you want sell the Meade and go on. You won't lose more than $25,
          and you will have learned alot about how the mechanics of your scope
          works.

          Oh, I would suggest getting the EZ Focus Kit from Scopestuff.com or
          the NC-SCT focuser upgrade from http://www.sunflower.com/%
          7Eclafever/ezt/ncsct.html. I used the former, but a friend used the
          latter. We both are happy with the results, less image shift and
          smoother movement.

          --- In Meade-Uncensored@y..., "kb9ilt" <kb9ilt@m...> wrote:
          > Hi,
          >
          > I have a Meade 2080(8 inch SCT)and am thinking about adding an
          > electric focuser and a dew shield. Before doing so, I'm wondering
          > what good or bad experiences others have had with these two
          > accessories.
          >
          > I see that both Meade and JMI make electric focusers that will work
          > with my scope, but I wonder if one is better than the other. Any
          > comments on these two products? Do they really focus without any
          > shaking of the scope? Is the Meade worth the extra money?
          >
          > The dew shield by Meade is very expensive. I can't imagine that it
          > could be worth the added expense over competing shields other that
          it
          > matches the scope in color. I live in a rather light polluted area
          > and have heard that a dew shield will improve the performance of an
          > SCT by blocking out some of the nearby stray light. Has anyone
          > noticed that this is true to any significant exent?
          >
          > Thanks,
          >
          > Paul
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