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Clear skies + Polar alignment = Frustration!

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  • tegwilym
    Ok, I m new at this obviously. I just got my wedge for my LX90 and have been trying to figure out the polar alignment so I can take some pictures with my
    Message 1 of 14 , May 1 12:19 AM
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      Ok, I'm new at this obviously. I just got my wedge for my LX90 and
      have been trying to figure out the polar alignment so I can take
      some pictures with my webcam. The skies tonight in Seattle were
      super clear, all the galaxies were out, but I wasted most of the
      evening aligning, re-aligning, jumping up and down with frustration,
      then finally giving up and going inside.

      I get Polaris centered up in the view with the scope set to 90
      degrees, and the wedge set at 47 degrees (Seattle). I then do a 2
      star Autostar alignment and that goes fairly well.

      Now when I use the Autostar to goto the object, it works fine and
      usually is somehere in the view and just takes a little slewing to
      center it.

      Now the frustation. When taking images with the Vesta Pro SC
      camera, sometimes the object will look fine after 30 second
      exposure, then the next image will be streaked, one more will be
      streaked, then maybe a few good stable ones then more streaking.

      Is my Polar alignment procedures messed up, or have I just
      discovered the reason for an off-axis guider?

      I know that Polaris is not the actual pole, but off a few degrees,
      but figured for farily short exposures this would be minor, but
      maybe not....

      I guess a focal reducer would help also since the images come out
      really large through the camera.

      Ugh! Why do I always pick such complex hobbies? :-)

      Tom
    • Janet Miller
      Hi Tom, ... From: tegwilym To: Sent: Wednesday, May 01, 2002 2:19 AM Subject: [lx90] Clear skies + Polar
      Message 2 of 14 , May 1 5:46 AM
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        Hi Tom,

        ----- Original Message -----
        From: "tegwilym" <tegwilym@...>
        To: <lx90@yahoogroups.com>
        Sent: Wednesday, May 01, 2002 2:19 AM
        Subject: [lx90] Clear skies + Polar alignment = Frustration!


        > Ok, I'm new at this obviously. I just got my wedge for my LX90 and
        > have been trying to figure out the polar alignment so I can take
        > some pictures with my webcam. The skies tonight in Seattle were
        > super clear, all the galaxies were out, but I wasted most of the
        > evening aligning, re-aligning, jumping up and down with frustration,
        > then finally giving up and going inside.

        Ahh, always best to observe when you have the chance. If things aren't
        working out for you photography-wise, don't allow yourself to get all
        frustrated and upset. Take some time and just observe for a while, and mark
        up the night as an experience bulder. After all, those faint fuzzy's aren't
        going anywhere real fast, in fact they'll be there for your children's
        children's children :o)

        >
        > I get Polaris centered up in the view with the scope set to 90
        > degrees, and the wedge set at 47 degrees (Seattle). I then do a 2
        > star Autostar alignment and that goes fairly well.

        Try a 1 star alignment, it's much more precise (forces you to adjust the
        wedge for the NCP) or Clay's Kochab's clock method.

        >
        > Now when I use the Autostar to goto the object, it works fine and
        > usually is somehere in the view and just takes a little slewing to
        > center it.
        >
        > Now the frustation. When taking images with the Vesta Pro SC
        > camera, sometimes the object will look fine after 30 second
        > exposure, then the next image will be streaked, one more will be
        > streaked, then maybe a few good stable ones then more streaking.

        Could have been lots of things. Wind is notorious on my web cam, especially
        when the dewshield is on. Don't forget that our wedge's make the scope much
        less stable. Check your images, see where the streaks were coming from. Are
        they in the RA direction? You may need to set a "custom" tracking rate; most
        of us have in Polar mode. Try observing with the highest power EP you have
        on a star, and see if you notice any movement. You may need to take up some
        backlash in your gears by re-training or mechanically adjusting the worm.


        > Is my Polar alignment procedures messed up, or have I just
        > discovered the reason for an off-axis guider?

        For 30 sec exposures, a OAG shouldn't be neccesary. For over a minute or
        two, yes.
        >
        > I know that Polaris is not the actual pole, but off a few degrees,
        > but figured for farily short exposures this would be minor, but
        > maybe not....

        About 44 minutes, less than a degree. You're correct for short (under 1
        minute) exposures at low magnifications, you should be fine. Higher
        magnifications and longer exposure times will begin to show the effects of
        field rotation and drift, if your alignment is far off. This also depends on
        what area of the sky you're imaging as well.

        >
        > I guess a focal reducer would help also since the images come out
        > really large through the camera.

        Depends on the object you're imaging, but yes, a reducer/corrector can help
        with some.
        >
        > Ugh! Why do I always pick such complex hobbies? :-)

        At least you aren't alone - lol.

        - Jan





        ---
        *** Virus free ***
        Checked by AVG anti-virus system (http://www.grisoft.com).
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      • Clay Sherrod
        Ugh! Why do I always pick such complex hobbies? :-) At least you aren t alone - lol.... I like to believe that we pick such complex hobbies because we
        Message 3 of 14 , May 1 7:07 AM
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          "> Ugh! Why do I always pick such complex hobbies? :-)

          At least you aren't alone - lol...."

          I like to believe that we "pick such complex hobbies" because we have complex minds.

          The universe, its exploration and subsequent discovery, and its objects are apples on a tree of knowledge that are there for the taking.

          We all chose different routes to find the answers - interestingly which will NEVER be entirely known, only pondered - but the ultimate trip is the same.

          "Complex" ....or compelling? We are all bitten by the bug of the business of discovery.

          Dr. Clay


          ----- Original Message -----
          From: Janet Miller
          To: lx90@yahoogroups.com
          Sent: Wednesday, May 01, 2002 7:46 AM
          Subject: Re: [lx90] Clear skies + Polar alignment = Frustration!


          Hi Tom,

          ----- Original Message -----
          From: "tegwilym" <tegwilym@...>
          To: <lx90@yahoogroups.com>
          Sent: Wednesday, May 01, 2002 2:19 AM
          Subject: [lx90] Clear skies + Polar alignment = Frustration!


          > Ok, I'm new at this obviously. I just got my wedge for my LX90 and
          > have been trying to figure out the polar alignment so I can take
          > some pictures with my webcam. The skies tonight in Seattle were
          > super clear, all the galaxies were out, but I wasted most of the
          > evening aligning, re-aligning, jumping up and down with frustration,
          > then finally giving up and going inside.

          Ahh, always best to observe when you have the chance. If things aren't
          working out for you photography-wise, don't allow yourself to get all
          frustrated and upset. Take some time and just observe for a while, and mark
          up the night as an experience bulder. After all, those faint fuzzy's aren't
          going anywhere real fast, in fact they'll be there for your children's
          children's children :o)

          >
          > I get Polaris centered up in the view with the scope set to 90
          > degrees, and the wedge set at 47 degrees (Seattle). I then do a 2
          > star Autostar alignment and that goes fairly well.

          Try a 1 star alignment, it's much more precise (forces you to adjust the
          wedge for the NCP) or Clay's Kochab's clock method.

          >
          > Now when I use the Autostar to goto the object, it works fine and
          > usually is somehere in the view and just takes a little slewing to
          > center it.
          >
          > Now the frustation. When taking images with the Vesta Pro SC
          > camera, sometimes the object will look fine after 30 second
          > exposure, then the next image will be streaked, one more will be
          > streaked, then maybe a few good stable ones then more streaking.

          Could have been lots of things. Wind is notorious on my web cam, especially
          when the dewshield is on. Don't forget that our wedge's make the scope much
          less stable. Check your images, see where the streaks were coming from. Are
          they in the RA direction? You may need to set a "custom" tracking rate; most
          of us have in Polar mode. Try observing with the highest power EP you have
          on a star, and see if you notice any movement. You may need to take up some
          backlash in your gears by re-training or mechanically adjusting the worm.


          > Is my Polar alignment procedures messed up, or have I just
          > discovered the reason for an off-axis guider?

          For 30 sec exposures, a OAG shouldn't be neccesary. For over a minute or
          two, yes.
          >
          > I know that Polaris is not the actual pole, but off a few degrees,
          > but figured for farily short exposures this would be minor, but
          > maybe not....

          About 44 minutes, less than a degree. You're correct for short (under 1
          minute) exposures at low magnifications, you should be fine. Higher
          magnifications and longer exposure times will begin to show the effects of
          field rotation and drift, if your alignment is far off. This also depends on
          what area of the sky you're imaging as well.

          >
          > I guess a focal reducer would help also since the images come out
          > really large through the camera.

          Depends on the object you're imaging, but yes, a reducer/corrector can help
          with some.
          >
          > Ugh! Why do I always pick such complex hobbies? :-)

          At least you aren't alone - lol.

          - Jan





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          [Non-text portions of this message have been removed]
        • randckrejci
          Janet s advice is great...I ll just offer a morsel or 2 more... The Vesta has very small pixels and shows tracking errors quickly. Since the LX-90 has no PEC,
          Message 4 of 14 , May 1 7:49 AM
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            Janet's advice is great...I'll just offer a morsel or 2 more...

            The Vesta has very small pixels and shows tracking errors quickly.
            Since the LX-90 has no PEC, you will see the periodic error coming in
            fits and spurts like you mention. It's essentially a sine wave, so
            if you're exposing when the rate of change is great, you'll get
            streaks. If you're exposing when PE(periodic error) is near the peak
            of the sin wave, you'll get less shift. With the LX-90, you'll get
            +/- 15 arcsec error over a 9 minute period.

            Also, like Janet said, you may (probably) need to set a custom
            tracking rate. Start around +12 and see if that's pretty close.
            Just look a the image and see if it has significant drift over a 9
            minute period. It will drift with the PE, but the drift should
            center itself.

            But at high magnification, the longest unguided you are going to be
            able to fairly consistently get without significant streaking is 20-
            30 seconds. Adding focal reducers helps alot, and is highly
            recommended, especially with the Vestas.


            Rick Krejci
            http://www.ricksastro.com


            --- In lx90@y..., "tegwilym" <tegwilym@a...> wrote:
            > Ok, I'm new at this obviously. I just got my wedge for my LX90 and
            > have been trying to figure out the polar alignment so I can take
            > some pictures with my webcam. The skies tonight in Seattle were
            > super clear, all the galaxies were out, but I wasted most of the
            > evening aligning, re-aligning, jumping up and down with
            frustration,
            > then finally giving up and going inside.
            >
            > I get Polaris centered up in the view with the scope set to 90
            > degrees, and the wedge set at 47 degrees (Seattle). I then do a 2
            > star Autostar alignment and that goes fairly well.
            >
            > Now when I use the Autostar to goto the object, it works fine and
            > usually is somehere in the view and just takes a little slewing to
            > center it.
            >
            > Now the frustation. When taking images with the Vesta Pro SC
            > camera, sometimes the object will look fine after 30 second
            > exposure, then the next image will be streaked, one more will be
            > streaked, then maybe a few good stable ones then more streaking.
            >
            > Is my Polar alignment procedures messed up, or have I just
            > discovered the reason for an off-axis guider?
            >
            > I know that Polaris is not the actual pole, but off a few degrees,
            > but figured for farily short exposures this would be minor, but
            > maybe not....
            >
            > I guess a focal reducer would help also since the images come out
            > really large through the camera.
            >
            > Ugh! Why do I always pick such complex hobbies? :-)
            >
            > Tom
          • Gregory A. Pruden
            Hi Rick, Is there an image posted somewhere that shows the PEC related streaks or would someone post an image that has the pec type of streaking so that we
            Message 5 of 14 , May 1 8:46 AM
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              Hi Rick,
              Is there an image posted somewhere that shows the PEC related streaks or
              would someone post an image that has the pec type of streaking so that we
              could see what this looks like?
              Gregory

              -----Original Message-----
              From: randckrejci [mailto:rjkrejci@...]
              Sent: Wednesday, May 01, 2002 10:50 AM
              To: lx90@yahoogroups.com
              Subject: [lx90] Re: Clear skies + Polar alignment = Frustration!

              Janet's advice is great...I'll just offer a morsel or 2 more...

              The Vesta has very small pixels and shows tracking errors quickly.
              Since the LX-90 has no PEC, you will see the periodic error coming in
              fits and spurts like you mention. It's essentially a sine wave, so
              if you're exposing when the rate of change is great, you'll get
              streaks. If you're exposing when PE(periodic error) is near the peak
              of the sin wave, you'll get less shift. With the LX-90, you'll get
              +/- 15 arcsec error over a 9 minute period.

              Also, like Janet said, you may (probably) need to set a custom
              tracking rate. Start around +12 and see if that's pretty close.
              Just look a the image and see if it has significant drift over a 9
              minute period. It will drift with the PE, but the drift should
              center itself.

              But at high magnification, the longest unguided you are going to be
              able to fairly consistently get without significant streaking is 20-
              30 seconds. Adding focal reducers helps alot, and is highly
              recommended, especially with the Vestas.


              Rick Krejci
              http://www.ricksastro.com


              --- In lx90@y..., "tegwilym" <tegwilym@a...> wrote:
              > Ok, I'm new at this obviously. I just got my wedge for my LX90 and
              > have been trying to figure out the polar alignment so I can take
              > some pictures with my webcam. The skies tonight in Seattle were
              > super clear, all the galaxies were out, but I wasted most of the
              > evening aligning, re-aligning, jumping up and down with
              frustration,
              > then finally giving up and going inside.
              >
              > I get Polaris centered up in the view with the scope set to 90
              > degrees, and the wedge set at 47 degrees (Seattle). I then do a 2
              > star Autostar alignment and that goes fairly well.
              >
              > Now when I use the Autostar to goto the object, it works fine and
              > usually is somehere in the view and just takes a little slewing to
              > center it.
              >
              > Now the frustation. When taking images with the Vesta Pro SC
              > camera, sometimes the object will look fine after 30 second
              > exposure, then the next image will be streaked, one more will be
              > streaked, then maybe a few good stable ones then more streaking.
              >
              > Is my Polar alignment procedures messed up, or have I just
              > discovered the reason for an off-axis guider?
              >
              > I know that Polaris is not the actual pole, but off a few degrees,
              > but figured for farily short exposures this would be minor, but
              > maybe not....
              >
              > I guess a focal reducer would help also since the images come out
              > really large through the camera.
              >
              > Ugh! Why do I always pick such complex hobbies? :-)
              >
              > Tom



              To view the LX90 Online FAQ, visit: http://faq.lx-90.com

              To unsubscribe from this group, send an email to:
              lx90-unsubscribe@yahoogroups.com

              Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
            • tegwilym
              ... fuzzy s aren t ... children s ... Good point! I just often get so wrapped up in fiddling with things I just forget to relax and view things with my eyes
              Message 6 of 14 , May 1 9:33 AM
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                > Take some time and just observe for a while, and mark
                > up the night as an experience bulder. After all, those faint
                fuzzy's aren't
                > going anywhere real fast, in fact they'll be there for your
                children's
                > children's children :o)


                Good point! I just often get so wrapped up in fiddling with things
                I just forget to relax and view things with my eyes rather than
                electronic gadgets. Yeah, those photons I was gathering in my
                bucket last night are older than mankind, so I need to just slow
                down a bit. :-)





                > Try observing with the highest power EP you have
                > on a star, and see if you notice any movement. You may need to
                take up some
                > backlash in your gears by re-training or mechanically adjusting
                the worm.


                That sounds like a good idea. Actually, I haven't even trained the
                motors on this scope yet. I even updated the firmware in the
                Autostar a few weeks ago (now there is another update out). The
                training that you mention, that is the same thing that I do with a
                distant fixed object like Polaris right?
                I did get the scope collimated though, and as far as I can tell I
                got it pretty close. Of course this is totally unrelated, but it is
                a small accomplishment for me with this fancy new scope!



                > For 30 sec exposures, a OAG shouldn't be neccesary. For over a
                minute or
                > two, yes.


                Ok good. It seems that 30 seconds and some camera adjustments can
                pick up a lot of stuff pretty well (at least M13 which is the only
                thing I have had any luck with so far).
              • tegwilym
                ... quickly. ... in ... Ok good. Then my scope is most likely normal. I was wondering if there was something wrong with my motor, but then I just have to
                Message 7 of 14 , May 1 9:41 AM
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                  > The Vesta has very small pixels and shows tracking errors
                  quickly.
                  > Since the LX-90 has no PEC, you will see the periodic error coming
                  in
                  > fits and spurts like you mention.


                  Ok good. Then my scope is most likely normal. I was wondering if
                  there was something wrong with my motor, but then I just have to
                  realize that the Vesta has a HUGE amount of magnification so even a
                  very tiny movement will show up. M-13 more than fills the view of
                  the camera, so I would have to take a bunch of photos and make a
                  mosaic to get the whole thing in there.




                  > Also, like Janet said, you may (probably) need to set a custom
                  > tracking rate. Start around +12 and see if that's pretty close.



                  So do I calibrate this in the Autostar?



                  > But at high magnification, the longest unguided you are going to
                  be
                  > able to fairly consistently get without significant streaking is
                  20-
                  > 30 seconds. Adding focal reducers helps alot, and is highly
                  > recommended, especially with the Vestas.


                  Yep. I have realized that now from my experiments. Any
                  recommendation for a reducer? I have noticed that many of the deep
                  sky objects are fairly large so I think I'll definately be
                  interested in a reducer for one of my next additions. Along with
                  more eyepices, T-adaptors, more books, software.....etc.

                  Not only do these things suck photons, but also $$$ :-)

                  So much fun though. I find myself getting all excited every night
                  that it clears up. I just have to take that thing out and mess with
                  it.

                  Tom
                • tegwilym
                  ... have complex minds. I guess so! I m also kind of stubborn when it comes to complex new hobbies. I get kind of addicted or something and end up spending a
                  Message 8 of 14 , May 1 9:46 AM
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                    > I like to believe that we "pick such complex hobbies" because we
                    have complex minds.


                    I guess so!
                    I'm also kind of stubborn when it comes to complex new hobbies. I
                    get kind of addicted or something and end up spending a lot of time
                    figuring things out. Even if I get frustrated I just have so much
                    fun doing it. My last major complex hobby that I figured out was
                    satellite imaging from polar orbiting weather satellites. I now
                    have a pretty decent receiving station at home. Check this out:

                    http://www.geocities.com/tegwilym

                    I haven't updated it in a while, so the images are a little old.

                    Anyway, that is off the topic and looking down instead of up.

                    Thanks for the advice Janet, Dr. Clay, Jon....and others.

                    Tom
                  • randckrejci
                    Oh, I m sure there are hundreds (more than without) :) But basically, PEC streaking indistinguishable from slow or fast tracking streaking in that they are all
                    Message 9 of 14 , May 1 11:02 AM
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                      Oh, I'm sure there are hundreds (more than without) :)

                      But basically, PEC streaking indistinguishable from slow or fast
                      tracking streaking in that they are all isolated to the RA axis,
                      causing horizontal streaks for normal camera positioning. It's just
                      that PEC will oscillate back and forth while slow or fast tracking
                      will continuously drift.

                      That'll combine with any dec drift caused by imperfect polar
                      alignment, with the end result being a diagonal movement.

                      Like Janet said, the easiest way to see this is to put as high of
                      magnification eyepiece (preferrably reticle) you have, lock it on a
                      moderately bright star and observe. It will move back and forth. If
                      it does a slow side-to-side movement every 9.5 minutes, that's PE.
                      If it's drifting out of the eyepiece in RA, that's probably tracking
                      error. If it's drifting in DEC, that's polar misalignment.

                      Rick
                      http://www.ricksastro.com

                      --- In lx90@y..., "Gregory A. Pruden" <gregory@i...> wrote:
                      > Hi Rick,
                      > Is there an image posted somewhere that shows the PEC related
                      streaks or
                      > would someone post an image that has the pec type of streaking so
                      that we
                      > could see what this looks like?
                      > Gregory
                      >
                      > -----Original Message-----
                      > From: randckrejci [mailto:rjkrejci@e...]
                      > Sent: Wednesday, May 01, 2002 10:50 AM
                      > To: lx90@y...
                      > Subject: [lx90] Re: Clear skies + Polar alignment = Frustration!
                      >
                      > Janet's advice is great...I'll just offer a morsel or 2 more...
                      >
                      > The Vesta has very small pixels and shows tracking errors quickly.
                      > Since the LX-90 has no PEC, you will see the periodic error coming
                      in
                      > fits and spurts like you mention. It's essentially a sine wave, so
                      > if you're exposing when the rate of change is great, you'll get
                      > streaks. If you're exposing when PE(periodic error) is near the
                      peak
                      > of the sin wave, you'll get less shift. With the LX-90, you'll get
                      > +/- 15 arcsec error over a 9 minute period.
                      >
                      > Also, like Janet said, you may (probably) need to set a custom
                      > tracking rate. Start around +12 and see if that's pretty close.
                      > Just look a the image and see if it has significant drift over a 9
                      > minute period. It will drift with the PE, but the drift should
                      > center itself.
                      >
                      > But at high magnification, the longest unguided you are going to be
                      > able to fairly consistently get without significant streaking is 20-
                      > 30 seconds. Adding focal reducers helps alot, and is highly
                      > recommended, especially with the Vestas.
                      >
                      >
                      > Rick Krejci
                      > http://www.ricksastro.com
                      >
                      >
                      > --- In lx90@y..., "tegwilym" <tegwilym@a...> wrote:
                      > > Ok, I'm new at this obviously. I just got my wedge for my LX90
                      and
                      > > have been trying to figure out the polar alignment so I can take
                      > > some pictures with my webcam. The skies tonight in Seattle were
                      > > super clear, all the galaxies were out, but I wasted most of the
                      > > evening aligning, re-aligning, jumping up and down with
                      > frustration,
                      > > then finally giving up and going inside.
                      > >
                      > > I get Polaris centered up in the view with the scope set to 90
                      > > degrees, and the wedge set at 47 degrees (Seattle). I then do a
                      2
                      > > star Autostar alignment and that goes fairly well.
                      > >
                      > > Now when I use the Autostar to goto the object, it works fine and
                      > > usually is somehere in the view and just takes a little slewing
                      to
                      > > center it.
                      > >
                      > > Now the frustation. When taking images with the Vesta Pro SC
                      > > camera, sometimes the object will look fine after 30 second
                      > > exposure, then the next image will be streaked, one more will be
                      > > streaked, then maybe a few good stable ones then more streaking.
                      > >
                      > > Is my Polar alignment procedures messed up, or have I just
                      > > discovered the reason for an off-axis guider?
                      > >
                      > > I know that Polaris is not the actual pole, but off a few
                      degrees,
                      > > but figured for farily short exposures this would be minor, but
                      > > maybe not....
                      > >
                      > > I guess a focal reducer would help also since the images come out
                      > > really large through the camera.
                      > >
                      > > Ugh! Why do I always pick such complex hobbies? :-)
                      > >
                      > > Tom
                      >
                      >
                      >
                      > To view the LX90 Online FAQ, visit: http://faq.lx-90.com
                      >
                      > To unsubscribe from this group, send an email to:
                      > lx90-unsubscribe@y...
                      >
                      > Your use of Yahoo! Groups is subject to
                      http://docs.yahoo.com/info/terms/
                    • randckrejci
                      ... If I remember right, it s under the setup telescope menu as tracking rate or something like that, where you can choose Custom and enter +12. You have to
                      Message 10 of 14 , May 1 11:06 AM
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                        --- In lx90@y..., "tegwilym" <tegwilym@a...> wrote:
                        >
                        > > Also, like Janet said, you may (probably) need to set a custom
                        > > tracking rate. Start around +12 and see if that's pretty close.
                        >
                        >
                        >
                        > So do I calibrate this in the Autostar?

                        If I remember right, it's under the setup telescope menu as tracking
                        rate or something like that, where you can choose Custom and enter
                        +12. You have to re-enter it on each powerup!

                        >
                        >
                        >
                        > > But at high magnification, the longest unguided you are going to
                        > be
                        > > able to fairly consistently get without significant streaking is
                        > 20-
                        > > 30 seconds. Adding focal reducers helps alot, and is highly
                        > > recommended, especially with the Vestas.
                        >
                        >
                        > Yep. I have realized that now from my experiments. Any
                        > recommendation for a reducer? I have noticed that many of the deep
                        > sky objects are fairly large so I think I'll definately be
                        > interested in a reducer for one of my next additions. Along with
                        > more eyepices, T-adaptors, more books, software.....etc.
                        >
                        > Not only do these things suck photons, but also $$$ :-)
                        >
                        > So much fun though. I find myself getting all excited every night
                        > that it clears up. I just have to take that thing out and mess
                        with
                        > it.
                        >
                        > Tom

                        The Meade f3.3 reducer is great fun with the Vesta...will get you
                        much wider FOV's as well as brighter images. There are also other's
                        out there that are a little less expensive.

                        Rick
                        http://www.ricksastro.com
                      • Janet Miller
                        ... From: tegwilym To: Sent: Wednesday, May 01, 2002 11:33 AM Subject: [lx90] Re: Clear skies + Polar alignment =
                        Message 11 of 14 , May 1 12:34 PM
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                          ----- Original Message -----
                          From: "tegwilym" <tegwilym@...>
                          To: <lx90@yahoogroups.com>
                          Sent: Wednesday, May 01, 2002 11:33 AM
                          Subject: [lx90] Re: Clear skies + Polar alignment = Frustration!



                          > That sounds like a good idea. Actually, I haven't even trained the
                          > motors on this scope yet. I even updated the firmware in the
                          > Autostar a few weeks ago (now there is another update out). The
                          > training that you mention, that is the same thing that I do with a
                          > distant fixed object like Polaris right?

                          That's correct. Use a high power EP and a slow slewing speed when you're
                          training. If you overshoot the target while re-centering, or accidentally
                          hit the wrong button, or reverse the slewing direction, start all over
                          again. Good training is important.

                          > I did get the scope collimated though, and as far as I can tell I
                          > got it pretty close. Of course this is totally unrelated, but it is
                          > a small accomplishment for me with this fancy new scope!

                          Take your time. It all comes together soon enough :o)

                          - Jan


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                        • Janet Miller
                          Hi Gregory, I believe that S&T had an image of the PE when they did the review of the LX90 about a year ago. The only problem is that S&T s new website charges
                          Message 12 of 14 , May 1 12:37 PM
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                            Hi Gregory,

                            I believe that S&T had an image of the PE when they did the review of the
                            LX90 about a year ago. The only problem is that S&T's new website charges
                            now to read their online reviews, so that image is unavailable unless you
                            want to pay.

                            I've never taken one myself ( intentionally, that is ) :o)

                            - Jan

                            ----- Original Message -----
                            From: "Gregory A. Pruden" <gregory@...>
                            To: <lx90@yahoogroups.com>
                            Sent: Wednesday, May 01, 2002 10:46 AM
                            Subject: RE: [lx90] Re: Clear skies + Polar alignment = Frustration!


                            > Hi Rick,
                            > Is there an image posted somewhere that shows the PEC related streaks or
                            > would someone post an image that has the pec type of streaking so that we
                            > could see what this looks like?
                            > Gregory
                            >
                            > -----Original Message-----
                            > From: randckrejci [mailto:rjkrejci@...]
                            > Sent: Wednesday, May 01, 2002 10:50 AM
                            > To: lx90@yahoogroups.com
                            > Subject: [lx90] Re: Clear skies + Polar alignment = Frustration!
                            >
                            > Janet's advice is great...I'll just offer a morsel or 2 more...
                            >
                            > The Vesta has very small pixels and shows tracking errors quickly.
                            > Since the LX-90 has no PEC, you will see the periodic error coming in
                            > fits and spurts like you mention. It's essentially a sine wave, so
                            > if you're exposing when the rate of change is great, you'll get
                            > streaks. If you're exposing when PE(periodic error) is near the peak
                            > of the sin wave, you'll get less shift. With the LX-90, you'll get
                            > +/- 15 arcsec error over a 9 minute period.
                            >
                            > Also, like Janet said, you may (probably) need to set a custom
                            > tracking rate. Start around +12 and see if that's pretty close.
                            > Just look a the image and see if it has significant drift over a 9
                            > minute period. It will drift with the PE, but the drift should
                            > center itself.
                            >
                            > But at high magnification, the longest unguided you are going to be
                            > able to fairly consistently get without significant streaking is 20-
                            > 30 seconds. Adding focal reducers helps alot, and is highly
                            > recommended, especially with the Vestas.
                            >
                            >
                            > Rick Krejci
                            > http://www.ricksastro.com
                            >
                            >
                            > --- In lx90@y..., "tegwilym" <tegwilym@a...> wrote:
                            > > Ok, I'm new at this obviously. I just got my wedge for my LX90 and
                            > > have been trying to figure out the polar alignment so I can take
                            > > some pictures with my webcam. The skies tonight in Seattle were
                            > > super clear, all the galaxies were out, but I wasted most of the
                            > > evening aligning, re-aligning, jumping up and down with
                            > frustration,
                            > > then finally giving up and going inside.
                            > >
                            > > I get Polaris centered up in the view with the scope set to 90
                            > > degrees, and the wedge set at 47 degrees (Seattle). I then do a 2
                            > > star Autostar alignment and that goes fairly well.
                            > >
                            > > Now when I use the Autostar to goto the object, it works fine and
                            > > usually is somehere in the view and just takes a little slewing to
                            > > center it.
                            > >
                            > > Now the frustation. When taking images with the Vesta Pro SC
                            > > camera, sometimes the object will look fine after 30 second
                            > > exposure, then the next image will be streaked, one more will be
                            > > streaked, then maybe a few good stable ones then more streaking.
                            > >
                            > > Is my Polar alignment procedures messed up, or have I just
                            > > discovered the reason for an off-axis guider?
                            > >
                            > > I know that Polaris is not the actual pole, but off a few degrees,
                            > > but figured for farily short exposures this would be minor, but
                            > > maybe not....
                            > >
                            > > I guess a focal reducer would help also since the images come out
                            > > really large through the camera.
                            > >
                            > > Ugh! Why do I always pick such complex hobbies? :-)
                            > >
                            > > Tom
                            >
                            >
                            >
                            > To view the LX90 Online FAQ, visit: http://faq.lx-90.com
                            >
                            > To unsubscribe from this group, send an email to:
                            > lx90-unsubscribe@yahoogroups.com
                            >
                            > Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
                            >
                            >
                            >
                            > To view the LX90 Online FAQ, visit: http://faq.lx-90.com
                            >
                            > To unsubscribe from this group, send an email to:
                            > lx90-unsubscribe@yahoogroups.com
                            >
                            > Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
                            >
                            >


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                          • mondior63
                            ... review of the ... website charges ... unless you ... Hi everyone, I found the July issue of S&T with the LX90 review. I scanned the picture of the Periodic
                            Message 13 of 14 , May 1 1:55 PM
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                              --- In lx90@y..., "Janet Miller" <LuvJanet@s...> wrote:
                              > Hi Gregory,
                              >
                              > I believe that S&T had an image of the PE when they did the
                              review of the
                              > LX90 about a year ago. The only problem is that S&T's new
                              website charges
                              > now to read their online reviews, so that image is unavailable
                              unless you
                              > want to pay.
                              >
                              > I've never taken one myself ( intentionally, that is ) :o)
                              >
                              > - Jan


                              Hi everyone,

                              I found the July issue of S&T with the LX90 review. I scanned the
                              picture of the Periodic error and posted in the phots section in
                              SamD's folder. It is titled, appropriately enough, "Periodic Error."

                              here is the link

                              http://photos.groups.yahoo.com/group/lx90/vwp?.dir=/Sam+D%2
                              7s&.src=gr&.dnm=Periodic+Error.jpg&.view=t&.done=http%3a

                              Sam DiRocco
                            • tegwilym
                              ... a ... If ... PE. ... tracking ... That s a good idea. I ll try to take a photo of my drift and see what opinions I get about it. From what I have read,
                              Message 14 of 14 , May 1 11:23 PM
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                                > Like Janet said, the easiest way to see this is to put as high of
                                > magnification eyepiece (preferrably reticle) you have, lock it on
                                a
                                > moderately bright star and observe. It will move back and forth.
                                If
                                > it does a slow side-to-side movement every 9.5 minutes, that's
                                PE.
                                > If it's drifting out of the eyepiece in RA, that's probably
                                tracking
                                > error.




                                That's a good idea. I'll try to take a photo of my drift and see
                                what opinions I get about it. From what I have read, it sounds like
                                the scopes are not perfect and always have a little error here and
                                there.

                                Tom
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