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Possible tilt in FSQ or STL-11000

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  • Tom Carrico
    Hi all, This is a the note I just sent to Art asking about recent changes in the behavior of my FSQ/STL-11000. Perhaps one of you has run across something
    Message 1 of 11 , Jul 1 1:49 AM
    • 0 Attachment
      Hi all,
      This is a the note I just sent to Art asking about recent changes in the
      behavior of my FSQ/STL-11000. Perhaps one of you has run across
      something similar. I can post some images of what I am talking about if
      that would help.

      Hi Art,
      I have had my FSQ for about 1.5 years. I have been using it with my
      STL-11000 with reasonable success, however I have noticed a change.
      Earlier in the year, I could take exposures and when using CCDInspector
      I would get a curvature of as low as 3%, typically in the 5-8% range.
      Stars looked perfect all across the field. This was with exposures as
      long as 10 minutes, I rarely go longer. Recently, in the past 2 months,
      I cannot reliably get curvature below 10%, and it is typically 12-15%.
      The stars are clearly less well focused in one corner compared to the
      rest of the image, very easy to see in the image. I have conducted some
      experiments where I focus at different areas of the CCD and there is
      definitely a sweet spot where the focus is best, usually about 25% out
      from the center, but most of the time this only improves the curvature
      to around 10% and it is not entirely reliable..I use a Robofocus to
      focus. I do not use FocusMax or anything like that, I sit inside my
      house and use the RoboFocus software to manually adjust focus.
      The only thing that is different is that I now leave the scope outside
      and under a cover for long periods of time, maybe a week at at time. It
      is not in a shed, just covered. One benefit is that it is always close
      to ambient. However I do wonder if keeping it in the clamps is somehow
      tweaking things. Before this year, I always took the scope in. Could it
      be how it is clamped? Is there a chance the CAA got loose? Any other
      source of potential tilt? Of course, I do not want to rule out the
      STL-11000 either, so I will take a look at that as well.

      Any hints?

      Thanks
      Tom Carrico
    • dvjbaja
      SBIG uses very thin shims under the STL camera adapter block. If you removed that recently and didn t know they were there, you may have lost them. I had SBIG
      Message 2 of 11 , Jul 2 12:22 PM
      • 0 Attachment
        SBIG uses very thin shims under the STL camera adapter block. If you
        removed that recently and didn't know they were there, you may have
        lost them. I had SBIG check and re-shim my camera. The results are
        near-perfect.





        --- In UncensoredTakGroup@yahoogroups.com, Tom Carrico <tom@...>
        wrote:
        >
        > Hi all,
        > This is a the note I just sent to Art asking about recent changes
        in the
        > behavior of my FSQ/STL-11000. Perhaps one of you has run across
        > something similar. I can post some images of what I am talking
        about if
        > that would help.
        >
        > Hi Art,
        > I have had my FSQ for about 1.5 years. I have been using it with
        my
        > STL-11000 with reasonable success, however I have noticed a
        change.
        > Earlier in the year, I could take exposures and when using
        CCDInspector
        > I would get a curvature of as low as 3%, typically in the 5-8%
        range.
        > Stars looked perfect all across the field. This was with exposures
        as
        > long as 10 minutes, I rarely go longer. Recently, in the past 2
        months,
        > I cannot reliably get curvature below 10%, and it is typically 12-
        15%.
        > The stars are clearly less well focused in one corner compared to
        the
        > rest of the image, very easy to see in the image. I have conducted
        some
        > experiments where I focus at different areas of the CCD and there
        is
        > definitely a sweet spot where the focus is best, usually about 25%
        out
        > from the center, but most of the time this only improves the
        curvature
        > to around 10% and it is not entirely reliable..I use a Robofocus
        to
        > focus. I do not use FocusMax or anything like that, I sit inside
        my
        > house and use the RoboFocus software to manually adjust focus.
        > The only thing that is different is that I now leave the scope
        outside
        > and under a cover for long periods of time, maybe a week at at
        time. It
        > is not in a shed, just covered. One benefit is that it is always
        close
        > to ambient. However I do wonder if keeping it in the clamps is
        somehow
        > tweaking things. Before this year, I always took the scope in.
        Could it
        > be how it is clamped? Is there a chance the CAA got loose? Any
        other
        > source of potential tilt? Of course, I do not want to rule out the
        > STL-11000 either, so I will take a look at that as well.
        >
        > Any hints?
        >
        > Thanks
        > Tom Carrico
        >
      • Tom Carrico
        Hi all, The note at the end of this email describes some issues I was having with my FSQ/STL-11000 system. Many of you responded with great suggestions for
        Message 3 of 11 , Aug 5, 2007
        • 0 Attachment
          Hi all,
          The note at the end of this email describes some issues I was having
          with my FSQ/STL-11000 system. Many of you responded with great
          suggestions for getting to the root of the problem. In the last couple
          weeks I have been trying a number of different configurations and have
          determined the following:

          - The STL-11000 appears to be fine. The distortion I see in the corner
          moves as one would expect as the camera is rotated using the CAA. Also,
          the distortion happens independent of the filter used (h-alpha, RGB or
          clear)
          - There is an optimal rotation angle for best imaging. Imagine standing
          behind the scope, looking up past the scope. The best possible images,
          in my setup, occur with the camera oriented so the cables are pointing
          to the left (in the RA direction). The distortion appears the worst when
          the camera is rotated such that the cables are pointing towards the ground.
          - The distortion always improved (image got better), as the scope
          pointed more towards the zenith.
          - Keep the focus lock knob loose. This really surprised me. In the past,
          I had always just barely tightened the knob, figuring that would help
          make the whole system a bit more rigid. However, apparently it increased
          the stress, possibly leading to tilt. Now, I make sure it is very loose
          and rely on the RoboFocus motor to keep the focuser from slipping.
          - Also discovered that the best focus was achieved by placing the star
          to be focused about 10-20% out from the center.
          - I plan on ordering an adapter from Precise Parts that will allow me to
          keep the focuser racked in. I will update when this arrives.

          Following all these tips, my images are now very flat, the stars are
          sharp to the corner and CCDInspector shows a curvature typically < 5%. A
          huge improvement. So, as I look back and wonder why there was a change
          for the worst, it seems that I was oriented in the worst possible place
          and tightening the focus lock too much.

          I want to thank everyone for their help, it really made a difference in
          driving this problem to a successful conclusion. The following image of
          NGC 7822 is the first using the list above. It was taken over the last
          few nights, with the moon a'glowing, but the air steady.

          http://www.ccdargo.com/ngc7822_fsq_halpha_stl.htm

          I would be interested in everyone's thoughts on this, and if these tips
          are of any help.

          Thanks
          Tom Carrico
          http://www.ccdargo.com


          Tom Carrico wrote:
          > Hi all,
          > This is a the note I just sent to Art asking about recent changes in
          > the behavior of my FSQ/STL-11000. Perhaps one of you has run across
          > something similar. I can post some images of what I am talking about
          > if that would help.
          >
          > Hi Art,
          > I have had my FSQ for about 1.5 years. I have been using it with my
          > STL-11000 with reasonable success, however I have noticed a change.
          > Earlier in the year, I could take exposures and when using
          > CCDInspector I would get a curvature of as low as 3%, typically in the
          > 5-8% range. Stars looked perfect all across the field. This was with
          > exposures as long as 10 minutes, I rarely go longer. Recently, in the
          > past 2 months, I cannot reliably get curvature below 10%, and it is
          > typically 12-15%. The stars are clearly less well focused in one
          > corner compared to the rest of the image, very easy to see in the
          > image. I have conducted some experiments where I focus at different
          > areas of the CCD and there is definitely a sweet spot where the focus
          > is best, usually about 25% out from the center, but most of the time
          > this only improves the curvature to around 10% and it is not entirely
          > reliable..I use a Robofocus to focus. I do not use FocusMax or
          > anything like that, I sit inside my house and use the RoboFocus
          > software to manually adjust focus.
          > The only thing that is different is that I now leave the scope outside
          > and under a cover for long periods of time, maybe a week at at time.
          > It is not in a shed, just covered. One benefit is that it is always
          > close to ambient. However I do wonder if keeping it in the clamps is
          > somehow tweaking things. Before this year, I always took the scope in.
          > Could it be how it is clamped? Is there a chance the CAA got loose?
          > Any other source of potential tilt? Of course, I do not want to rule
          > out the STL-11000 either, so I will take a look at that as well.
          >
          > Any hints?
          >
          > Thanks
          > Tom Carrico
          >
          >
        • sforster12
          Tom, I ve been living your nightmare. I added a Tak 2 1/2 extension, and no change. I also tightned my focus knob, I ll loosen it now. My tilt seemed to be
          Message 4 of 11 , Aug 5, 2007
          • 0 Attachment
            Tom,

            I've been living your nightmare.
            I added a Tak 2 1/2" extension, and no change. I also tightned my
            focus knob, I'll loosen it now. My tilt seemed to be best at 30
            degrees to the right of verticle, but I also rotated the camera such
            that the elongation was either in the x or y axis. The star
            elongation was less obvious that way. With a new baby at home(no one
            ever has an old baby) imaging time has been scarce.

            I'm off for a few days in a week, so I'll play around.I'll let
            youknow if I get things better.

            STU


            I'll try --- In UncensoredTakGroup@yahoogroups.com, Tom Carrico
            <tom@...> wrote:
            >
            > Hi all,
            > The note at the end of this email describes some issues I was
            having
            > with my FSQ/STL-11000 system. Many of you responded with great
            > suggestions for getting to the root of the problem. In the last
            couple
            > weeks I have been trying a number of different configurations and
            have
            > determined the following:
            >
            > - The STL-11000 appears to be fine. The distortion I see in the
            corner
            > moves as one would expect as the camera is rotated using the CAA.
            Also,
            > the distortion happens independent of the filter used (h-alpha, RGB
            or
            > clear)
            > - There is an optimal rotation angle for best imaging. Imagine
            standing
            > behind the scope, looking up past the scope. The best possible
            images,
            > in my setup, occur with the camera oriented so the cables are
            pointing
            > to the left (in the RA direction). The distortion appears the worst
            when
            > the camera is rotated such that the cables are pointing towards the
            ground.
            > - The distortion always improved (image got better), as the scope
            > pointed more towards the zenith.
            > - Keep the focus lock knob loose. This really surprised me. In the
            past,
            > I had always just barely tightened the knob, figuring that would
            help
            > make the whole system a bit more rigid. However, apparently it
            increased
            > the stress, possibly leading to tilt. Now, I make sure it is very
            loose
            > and rely on the RoboFocus motor to keep the focuser from slipping.
            > - Also discovered that the best focus was achieved by placing the
            star
            > to be focused about 10-20% out from the center.
            > - I plan on ordering an adapter from Precise Parts that will allow
            me to
            > keep the focuser racked in. I will update when this arrives.
            >
            > Following all these tips, my images are now very flat, the stars
            are
            > sharp to the corner and CCDInspector shows a curvature typically <
            5%. A
            > huge improvement. So, as I look back and wonder why there was a
            change
            > for the worst, it seems that I was oriented in the worst possible
            place
            > and tightening the focus lock too much.
            >
            > I want to thank everyone for their help, it really made a
            difference in
            > driving this problem to a successful conclusion. The following
            image of
            > NGC 7822 is the first using the list above. It was taken over the
            last
            > few nights, with the moon a'glowing, but the air steady.
            >
            > http://www.ccdargo.com/ngc7822_fsq_halpha_stl.htm
            >
            > I would be interested in everyone's thoughts on this, and if these
            tips
            > are of any help.
            >
            > Thanks
            > Tom Carrico
            > http://www.ccdargo.com
            >
            >
            > Tom Carrico wrote:
            > > Hi all,
            > > This is a the note I just sent to Art asking about recent changes
            in
            > > the behavior of my FSQ/STL-11000. Perhaps one of you has run
            across
            > > something similar. I can post some images of what I am talking
            about
            > > if that would help.
            > >
            > > Hi Art,
            > > I have had my FSQ for about 1.5 years. I have been using it with
            my
            > > STL-11000 with reasonable success, however I have noticed a
            change.
            > > Earlier in the year, I could take exposures and when using
            > > CCDInspector I would get a curvature of as low as 3%, typically
            in the
            > > 5-8% range. Stars looked perfect all across the field. This was
            with
            > > exposures as long as 10 minutes, I rarely go longer. Recently, in
            the
            > > past 2 months, I cannot reliably get curvature below 10%, and it
            is
            > > typically 12-15%. The stars are clearly less well focused in one
            > > corner compared to the rest of the image, very easy to see in the
            > > image. I have conducted some experiments where I focus at
            different
            > > areas of the CCD and there is definitely a sweet spot where the
            focus
            > > is best, usually about 25% out from the center, but most of the
            time
            > > this only improves the curvature to around 10% and it is not
            entirely
            > > reliable..I use a Robofocus to focus. I do not use FocusMax or
            > > anything like that, I sit inside my house and use the RoboFocus
            > > software to manually adjust focus.
            > > The only thing that is different is that I now leave the scope
            outside
            > > and under a cover for long periods of time, maybe a week at at
            time.
            > > It is not in a shed, just covered. One benefit is that it is
            always
            > > close to ambient. However I do wonder if keeping it in the clamps
            is
            > > somehow tweaking things. Before this year, I always took the
            scope in.
            > > Could it be how it is clamped? Is there a chance the CAA got
            loose?
            > > Any other source of potential tilt? Of course, I do not want to
            rule
            > > out the STL-11000 either, so I will take a look at that as well.
            > >
            > > Any hints?
            > >
            > > Thanks
            > > Tom Carrico
            > >
            > >
            >
          • Jim Miller
            Interesting Tom, I missed the earlier thread. I am having that problem with an FCT-100 and an 11000. I am cuprous how the camera is attached to the OTA. Would
            Message 5 of 11 , Aug 5, 2007
            • 0 Attachment
              Interesting Tom, I missed the earlier thread. I am having that problem with
              an FCT-100 and an 11000. I am cuprous how the camera is attached to the OTA.
              Would this be available in an earlier thread if I looked? Are there any
              images posted?

              thanks,

              Jim
              -----Original Message-----
              From: UncensoredTakGroup@yahoogroups.com
              [mailto:UncensoredTakGroup@yahoogroups.com]On Behalf Of Tom Carrico
              Sent: Sunday, August 05, 2007 6:59 PM
              Cc: UncensoredTakGroup@yahoogroups.com; SBIG@yahoogroups.com
              Subject: [UncensoredTakGroup] Update - Possible tilt in FSQ or STL-11000


              Hi all,
              The note at the end of this email describes some issues I was having
              with my FSQ/STL-11000 system. Many of you responded with great
              suggestions for getting to the root of the problem. In the last couple
              weeks I have been trying a number of different configurations and have
              determined the following:

              - The STL-11000 appears to be fine. The distortion I see in the corner
              moves as one would expect as the camera is rotated using the CAA. Also,
              the distortion happens independent of the filter used (h-alpha, RGB or
              clear)
              - There is an optimal rotation angle for best imaging. Imagine standing
              behind the scope, looking up past the scope. The best possible images,
              in my setup, occur with the camera oriented so the cables are pointing
              to the left (in the RA direction). The distortion appears the worst when
              the camera is rotated such that the cables are pointing towards the
              ground.
              - The distortion always improved (image got better), as the scope
              pointed more towards the zenith.
              - Keep the focus lock knob loose. This really surprised me. In the past,
              I had always just barely tightened the knob, figuring that would help
              make the whole system a bit more rigid. However, apparently it increased
              the stress, possibly leading to tilt. Now, I make sure it is very loose
              and rely on the RoboFocus motor to keep the focuser from slipping.
              - Also discovered that the best focus was achieved by placing the star
              to be focused about 10-20% out from the center.
              - I plan on ordering an adapter from Precise Parts that will allow me to
              keep the focuser racked in. I will update when this arrives.

              Following all these tips, my images are now very flat, the stars are
              sharp to the corner and CCDInspector shows a curvature typically < 5%. A
              huge improvement. So, as I look back and wonder why there was a change
              for the worst, it seems that I was oriented in the worst possible place
              and tightening the focus lock too much.

              I want to thank everyone for their help, it really made a difference in
              driving this problem to a successful conclusion. The following image of
              NGC 7822 is the first using the list above. It was taken over the last
              few nights, with the moon a'glowing, but the air steady.

              http://www.ccdargo.com/ngc7822_fsq_halpha_stl.htm

              I would be interested in everyone's thoughts on this, and if these tips
              are of any help.

              Thanks
              Tom Carrico
              http://www.ccdargo.com

              Tom Carrico wrote:
              > Hi all,
              > This is a the note I just sent to Art asking about recent changes in
              > the behavior of my FSQ/STL-11000. Perhaps one of you has run across
              > something similar. I can post some images of what I am talking about
              > if that would help.
              >
              > Hi Art,
              > I have had my FSQ for about 1.5 years. I have been using it with my
              > STL-11000 with reasonable success, however I have noticed a change.
              > Earlier in the year, I could take exposures and when using
              > CCDInspector I would get a curvature of as low as 3%, typically in the
              > 5-8% range. Stars looked perfect all across the field. This was with
              > exposures as long as 10 minutes, I rarely go longer. Recently, in the
              > past 2 months, I cannot reliably get curvature below 10%, and it is
              > typically 12-15%. The stars are clearly less well focused in one
              > corner compared to the rest of the image, very easy to see in the
              > image. I have conducted some experiments where I focus at different
              > areas of the CCD and there is definitely a sweet spot where the focus
              > is best, usually about 25% out from the center, but most of the time
              > this only improves the curvature to around 10% and it is not entirely
              > reliable..I use a Robofocus to focus. I do not use FocusMax or
              > anything like that, I sit inside my house and use the RoboFocus
              > software to manually adjust focus.
              > The only thing that is different is that I now leave the scope outside
              > and under a cover for long periods of time, maybe a week at at time.
              > It is not in a shed, just covered. One benefit is that it is always
              > close to ambient. However I do wonder if keeping it in the clamps is
              > somehow tweaking things. Before this year, I always took the scope in.
              > Could it be how it is clamped? Is there a chance the CAA got loose?
              > Any other source of potential tilt? Of course, I do not want to rule
              > out the STL-11000 either, so I will take a look at that as well.
              >
              > Any hints?
              >
              > Thanks
              > Tom Carrico
              >
              >






              [Non-text portions of this message have been removed]
            • Tom Carrico
              Hi Jim, Here is a closeup of one way to attach an STL to an FSQ using the Feldstein adapter. I also have a Precise Parts adapter which gets rid of one threaded
              Message 6 of 11 , Aug 5, 2007
              • 0 Attachment
                Hi Jim,
                Here is a closeup of one way to attach an STL to an FSQ using the
                Feldstein adapter. I also have a Precise Parts adapter which gets rid of
                one threaded connection, but I do not have a recent image. If you like,
                I can post that tomorrow.

                http://www.ccdargo.com/tak_feldstein.jpg

                Tom Carrico

                Jim Miller wrote:
                > Interesting Tom, I missed the earlier thread. I am having that problem with
                > an FCT-100 and an 11000. I am cuprous how the camera is attached to the OTA.
                > Would this be available in an earlier thread if I looked? Are there any
                > images posted?
                >
                > thanks,
                >
                > Jim
                > -----Original Message-----
                > From: UncensoredTakGroup@yahoogroups.com
                > [mailto:UncensoredTakGroup@yahoogroups.com]On Behalf Of Tom Carrico
                > Sent: Sunday, August 05, 2007 6:59 PM
                > Cc: UncensoredTakGroup@yahoogroups.com; SBIG@yahoogroups.com
                > Subject: [UncensoredTakGroup] Update - Possible tilt in FSQ or STL-11000
                >
                >
                > Hi all,
                > The note at the end of this email describes some issues I was having
                > with my FSQ/STL-11000 system. Many of you responded with great
                > suggestions for getting to the root of the problem. In the last couple
                > weeks I have been trying a number of different configurations and have
                > determined the following:
                >
                > - The STL-11000 appears to be fine. The distortion I see in the corner
                > moves as one would expect as the camera is rotated using the CAA. Also,
                > the distortion happens independent of the filter used (h-alpha, RGB or
                > clear)
                > - There is an optimal rotation angle for best imaging. Imagine standing
                > behind the scope, looking up past the scope. The best possible images,
                > in my setup, occur with the camera oriented so the cables are pointing
                > to the left (in the RA direction). The distortion appears the worst when
                > the camera is rotated such that the cables are pointing towards the
                > ground.
                > - The distortion always improved (image got better), as the scope
                > pointed more towards the zenith.
                > - Keep the focus lock knob loose. This really surprised me. In the past,
                > I had always just barely tightened the knob, figuring that would help
                > make the whole system a bit more rigid. However, apparently it increased
                > the stress, possibly leading to tilt. Now, I make sure it is very loose
                > and rely on the RoboFocus motor to keep the focuser from slipping.
                > - Also discovered that the best focus was achieved by placing the star
                > to be focused about 10-20% out from the center.
                > - I plan on ordering an adapter from Precise Parts that will allow me to
                > keep the focuser racked in. I will update when this arrives.
                >
                > Following all these tips, my images are now very flat, the stars are
                > sharp to the corner and CCDInspector shows a curvature typically < 5%. A
                > huge improvement. So, as I look back and wonder why there was a change
                > for the worst, it seems that I was oriented in the worst possible place
                > and tightening the focus lock too much.
                >
                > I want to thank everyone for their help, it really made a difference in
                > driving this problem to a successful conclusion. The following image of
                > NGC 7822 is the first using the list above. It was taken over the last
                > few nights, with the moon a'glowing, but the air steady.
                >
                > http://www.ccdargo.com/ngc7822_fsq_halpha_stl.htm
                >
                > I would be interested in everyone's thoughts on this, and if these tips
                > are of any help.
                >
                > Thanks
                > Tom Carrico
                > http://www.ccdargo.com
                >
                > Tom Carrico wrote:
                > > Hi all,
                > > This is a the note I just sent to Art asking about recent changes in
                > > the behavior of my FSQ/STL-11000. Perhaps one of you has run across
                > > something similar. I can post some images of what I am talking about
                > > if that would help.
                > >
                > > Hi Art,
                > > I have had my FSQ for about 1.5 years. I have been using it with my
                > > STL-11000 with reasonable success, however I have noticed a change.
                > > Earlier in the year, I could take exposures and when using
                > > CCDInspector I would get a curvature of as low as 3%, typically in the
                > > 5-8% range. Stars looked perfect all across the field. This was with
                > > exposures as long as 10 minutes, I rarely go longer. Recently, in the
                > > past 2 months, I cannot reliably get curvature below 10%, and it is
                > > typically 12-15%. The stars are clearly less well focused in one
                > > corner compared to the rest of the image, very easy to see in the
                > > image. I have conducted some experiments where I focus at different
                > > areas of the CCD and there is definitely a sweet spot where the focus
                > > is best, usually about 25% out from the center, but most of the time
                > > this only improves the curvature to around 10% and it is not entirely
                > > reliable..I use a Robofocus to focus. I do not use FocusMax or
                > > anything like that, I sit inside my house and use the RoboFocus
                > > software to manually adjust focus.
                > > The only thing that is different is that I now leave the scope outside
                > > and under a cover for long periods of time, maybe a week at at time.
                > > It is not in a shed, just covered. One benefit is that it is always
                > > close to ambient. However I do wonder if keeping it in the clamps is
                > > somehow tweaking things. Before this year, I always took the scope in.
                > > Could it be how it is clamped? Is there a chance the CAA got loose?
                > > Any other source of potential tilt? Of course, I do not want to rule
                > > out the STL-11000 either, so I will take a look at that as well.
                > >
                > > Any hints?
                > >
                > > Thanks
                > > Tom Carrico
                > >
                > >
                >
                >
                >
                >
                >
                >
                > [Non-text portions of this message have been removed]
                >
                >
                >
                >
                > Yahoo! Groups Links
                >
                >
                >
                >
                >
                >
              • Jim Miller
                Thanks Tom. I assume the part with vertical machining is Takahashi, and the knurled machined part is he feldstein adapter? That looks pretty solid. When I
                Message 7 of 11 , Aug 6, 2007
                • 0 Attachment
                  Thanks Tom. I assume the part with vertical machining is Takahashi, and the
                  "knurled" machined part is he feldstein adapter? That looks pretty solid.
                  When I did my test shot with the FCT100 I used a 2" nosepiece. looks like I
                  need to get a fekdstein adapter and whatever part I will need to attach to
                  the FCT100. I have a 10 minute sub of my test shot I can send you. I am
                  curious if your results looked the same.

                  many thanks for the info,

                  Jim


                  -----Original Message-----
                  From: UncensoredTakGroup@yahoogroups.com
                  [mailto:UncensoredTakGroup@yahoogroups.com]On Behalf Of Tom Carrico
                  Sent: Sunday, August 05, 2007 9:41 PM
                  To: UncensoredTakGroup@yahoogroups.com
                  Subject: Re: [UncensoredTakGroup] Update - Possible tilt in FSQ or STL-11000


                  Hi Jim,
                  Here is a closeup of one way to attach an STL to an FSQ using the
                  Feldstein adapter. I also have a Precise Parts adapter which gets rid of
                  one threaded connection, but I do not have a recent image. If you like,
                  I can post that tomorrow.

                  http://www.ccdargo.com/tak_feldstein.jpg

                  Tom Carrico

                  Jim Miller wrote:
                  > Interesting Tom, I missed the earlier thread. I am having that problem
                  with
                  > an FCT-100 and an 11000. I am cuprous how the camera is attached to the
                  OTA.
                  > Would this be available in an earlier thread if I looked? Are there any
                  > images posted?
                  >
                  > thanks,
                  >
                  > Jim
                  > -----Original Message-----
                  > From: UncensoredTakGroup@yahoogroups.com
                  > [mailto:UncensoredTakGroup@yahoogroups.com]On Behalf Of Tom Carrico
                  > Sent: Sunday, August 05, 2007 6:59 PM
                  > Cc: UncensoredTakGroup@yahoogroups.com; SBIG@yahoogroups.com
                  > Subject: [UncensoredTakGroup] Update - Possible tilt in FSQ or STL-11000
                  >
                  >
                  > Hi all,
                  > The note at the end of this email describes some issues I was having
                  > with my FSQ/STL-11000 system. Many of you responded with great
                  > suggestions for getting to the root of the problem. In the last couple
                  > weeks I have been trying a number of different configurations and have
                  > determined the following:
                  >
                  > - The STL-11000 appears to be fine. The distortion I see in the corner
                  > moves as one would expect as the camera is rotated using the CAA. Also,
                  > the distortion happens independent of the filter used (h-alpha, RGB or
                  > clear)
                  > - There is an optimal rotation angle for best imaging. Imagine standing
                  > behind the scope, looking up past the scope. The best possible images,
                  > in my setup, occur with the camera oriented so the cables are pointing
                  > to the left (in the RA direction). The distortion appears the worst when
                  > the camera is rotated such that the cables are pointing towards the
                  > ground.
                  > - The distortion always improved (image got better), as the scope
                  > pointed more towards the zenith.
                  > - Keep the focus lock knob loose. This really surprised me. In the past,
                  > I had always just barely tightened the knob, figuring that would help
                  > make the whole system a bit more rigid. However, apparently it increased
                  > the stress, possibly leading to tilt. Now, I make sure it is very loose
                  > and rely on the RoboFocus motor to keep the focuser from slipping.
                  > - Also discovered that the best focus was achieved by placing the star
                  > to be focused about 10-20% out from the center.
                  > - I plan on ordering an adapter from Precise Parts that will allow me to
                  > keep the focuser racked in. I will update when this arrives.
                  >
                  > Following all these tips, my images are now very flat, the stars are
                  > sharp to the corner and CCDInspector shows a curvature typically < 5%. A
                  > huge improvement. So, as I look back and wonder why there was a change
                  > for the worst, it seems that I was oriented in the worst possible place
                  > and tightening the focus lock too much.
                  >
                  > I want to thank everyone for their help, it really made a difference in
                  > driving this problem to a successful conclusion. The following image of
                  > NGC 7822 is the first using the list above. It was taken over the last
                  > few nights, with the moon a'glowing, but the air steady.
                  >
                  > http://www.ccdargo.com/ngc7822_fsq_halpha_stl.htm
                  >
                  > I would be interested in everyone's thoughts on this, and if these tips
                  > are of any help.
                  >
                  > Thanks
                  > Tom Carrico
                  > http://www.ccdargo.com
                  >
                  > Tom Carrico wrote:
                  > > Hi all,
                  > > This is a the note I just sent to Art asking about recent changes in
                  > > the behavior of my FSQ/STL-11000. Perhaps one of you has run across
                  > > something similar. I can post some images of what I am talking about
                  > > if that would help.
                  > >
                  > > Hi Art,
                  > > I have had my FSQ for about 1.5 years. I have been using it with my
                  > > STL-11000 with reasonable success, however I have noticed a change.
                  > > Earlier in the year, I could take exposures and when using
                  > > CCDInspector I would get a curvature of as low as 3%, typically in the
                  > > 5-8% range. Stars looked perfect all across the field. This was with
                  > > exposures as long as 10 minutes, I rarely go longer. Recently, in the
                  > > past 2 months, I cannot reliably get curvature below 10%, and it is
                  > > typically 12-15%. The stars are clearly less well focused in one
                  > > corner compared to the rest of the image, very easy to see in the
                  > > image. I have conducted some experiments where I focus at different
                  > > areas of the CCD and there is definitely a sweet spot where the focus
                  > > is best, usually about 25% out from the center, but most of the time
                  > > this only improves the curvature to around 10% and it is not entirely
                  > > reliable..I use a Robofocus to focus. I do not use FocusMax or
                  > > anything like that, I sit inside my house and use the RoboFocus
                  > > software to manually adjust focus.
                  > > The only thing that is different is that I now leave the scope outside
                  > > and under a cover for long periods of time, maybe a week at at time.
                  > > It is not in a shed, just covered. One benefit is that it is always
                  > > close to ambient. However I do wonder if keeping it in the clamps is
                  > > somehow tweaking things. Before this year, I always took the scope in.
                  > > Could it be how it is clamped? Is there a chance the CAA got loose?
                  > > Any other source of potential tilt? Of course, I do not want to rule
                  > > out the STL-11000 either, so I will take a look at that as well.
                  > >
                  > > Any hints?
                  > >
                  > > Thanks
                  > > Tom Carrico
                  > >
                  > >
                  >
                  >
                  >
                  >
                  >
                  >
                  > [Non-text portions of this message have been removed]
                  >
                  >
                  >
                  >
                  > Yahoo! Groups Links
                  >
                  >
                  >
                  >
                  >
                  >






                  [Non-text portions of this message have been removed]
                • Tom Carrico
                  Hi Jim, Yes, the Feldstein is between the camera and the knurled part and is very solid. With the Precise Parts adapter, the knurled Tak part and the Feldstein
                  Message 8 of 11 , Aug 6, 2007
                  • 0 Attachment
                    Hi Jim,
                    Yes, the Feldstein is between the camera and the knurled part and is
                    very solid. With the Precise Parts adapter, the knurled Tak part and the
                    Feldstein adapter are replaced by one piece, making it even more secure.
                    It is easy to believe you did not get perfectly square with the 2" nose
                    piece.
                    Go ahead and send the test shot, or post it somewhere that I can look at it.

                    Thanks
                    Tom Carrico

                    Jim Miller wrote:
                    > Thanks Tom. I assume the part with vertical machining is Takahashi, and the
                    > "knurled" machined part is he feldstein adapter? That looks pretty solid.
                    > When I did my test shot with the FCT100 I used a 2" nosepiece. looks like I
                    > need to get a fekdstein adapter and whatever part I will need to attach to
                    > the FCT100. I have a 10 minute sub of my test shot I can send you. I am
                    > curious if your results looked the same.
                    >
                    > many thanks for the info,
                    >
                    > Jim
                    >
                    >
                    > -----Original Message-----
                    > From: UncensoredTakGroup@yahoogroups.com
                    > [mailto:UncensoredTakGroup@yahoogroups.com]On Behalf Of Tom Carrico
                    > Sent: Sunday, August 05, 2007 9:41 PM
                    > To: UncensoredTakGroup@yahoogroups.com
                    > Subject: Re: [UncensoredTakGroup] Update - Possible tilt in FSQ or STL-11000
                    >
                    >
                    > Hi Jim,
                    > Here is a closeup of one way to attach an STL to an FSQ using the
                    > Feldstein adapter. I also have a Precise Parts adapter which gets rid of
                    > one threaded connection, but I do not have a recent image. If you like,
                    > I can post that tomorrow.
                    >
                    > http://www.ccdargo.com/tak_feldstein.jpg
                    >
                    > Tom Carrico
                    >
                    > Jim Miller wrote:
                    > > Interesting Tom, I missed the earlier thread. I am having that problem
                    > with
                    > > an FCT-100 and an 11000. I am cuprous how the camera is attached to the
                    > OTA.
                    > > Would this be available in an earlier thread if I looked? Are there any
                    > > images posted?
                    > >
                    > > thanks,
                    > >
                    > > Jim
                    > > -----Original Message-----
                    > > From: UncensoredTakGroup@yahoogroups.com
                    > > [mailto:UncensoredTakGroup@yahoogroups.com]On Behalf Of Tom Carrico
                    > > Sent: Sunday, August 05, 2007 6:59 PM
                    > > Cc: UncensoredTakGroup@yahoogroups.com; SBIG@yahoogroups.com
                    > > Subject: [UncensoredTakGroup] Update - Possible tilt in FSQ or STL-11000
                    > >
                    > >
                    > > Hi all,
                    > > The note at the end of this email describes some issues I was having
                    > > with my FSQ/STL-11000 system. Many of you responded with great
                    > > suggestions for getting to the root of the problem. In the last couple
                    > > weeks I have been trying a number of different configurations and have
                    > > determined the following:
                    > >
                    > > - The STL-11000 appears to be fine. The distortion I see in the corner
                    > > moves as one would expect as the camera is rotated using the CAA. Also,
                    > > the distortion happens independent of the filter used (h-alpha, RGB or
                    > > clear)
                    > > - There is an optimal rotation angle for best imaging. Imagine standing
                    > > behind the scope, looking up past the scope. The best possible images,
                    > > in my setup, occur with the camera oriented so the cables are pointing
                    > > to the left (in the RA direction). The distortion appears the worst when
                    > > the camera is rotated such that the cables are pointing towards the
                    > > ground.
                    > > - The distortion always improved (image got better), as the scope
                    > > pointed more towards the zenith.
                    > > - Keep the focus lock knob loose. This really surprised me. In the past,
                    > > I had always just barely tightened the knob, figuring that would help
                    > > make the whole system a bit more rigid. However, apparently it increased
                    > > the stress, possibly leading to tilt. Now, I make sure it is very loose
                    > > and rely on the RoboFocus motor to keep the focuser from slipping.
                    > > - Also discovered that the best focus was achieved by placing the star
                    > > to be focused about 10-20% out from the center.
                    > > - I plan on ordering an adapter from Precise Parts that will allow me to
                    > > keep the focuser racked in. I will update when this arrives.
                    > >
                    > > Following all these tips, my images are now very flat, the stars are
                    > > sharp to the corner and CCDInspector shows a curvature typically < 5%. A
                    > > huge improvement. So, as I look back and wonder why there was a change
                    > > for the worst, it seems that I was oriented in the worst possible place
                    > > and tightening the focus lock too much.
                    > >
                    > > I want to thank everyone for their help, it really made a difference in
                    > > driving this problem to a successful conclusion. The following image of
                    > > NGC 7822 is the first using the list above. It was taken over the last
                    > > few nights, with the moon a'glowing, but the air steady.
                    > >
                    > > http://www.ccdargo.com/ngc7822_fsq_halpha_stl.htm
                    > >
                    > > I would be interested in everyone's thoughts on this, and if these tips
                    > > are of any help.
                    > >
                    > > Thanks
                    > > Tom Carrico
                    > > http://www.ccdargo.com
                    > >
                    > > Tom Carrico wrote:
                    > > > Hi all,
                    > > > This is a the note I just sent to Art asking about recent changes in
                    > > > the behavior of my FSQ/STL-11000. Perhaps one of you has run across
                    > > > something similar. I can post some images of what I am talking about
                    > > > if that would help.
                    > > >
                    > > > Hi Art,
                    > > > I have had my FSQ for about 1.5 years. I have been using it with my
                    > > > STL-11000 with reasonable success, however I have noticed a change.
                    > > > Earlier in the year, I could take exposures and when using
                    > > > CCDInspector I would get a curvature of as low as 3%, typically in the
                    > > > 5-8% range. Stars looked perfect all across the field. This was with
                    > > > exposures as long as 10 minutes, I rarely go longer. Recently, in the
                    > > > past 2 months, I cannot reliably get curvature below 10%, and it is
                    > > > typically 12-15%. The stars are clearly less well focused in one
                    > > > corner compared to the rest of the image, very easy to see in the
                    > > > image. I have conducted some experiments where I focus at different
                    > > > areas of the CCD and there is definitely a sweet spot where the focus
                    > > > is best, usually about 25% out from the center, but most of the time
                    > > > this only improves the curvature to around 10% and it is not entirely
                    > > > reliable..I use a Robofocus to focus. I do not use FocusMax or
                    > > > anything like that, I sit inside my house and use the RoboFocus
                    > > > software to manually adjust focus.
                    > > > The only thing that is different is that I now leave the scope outside
                    > > > and under a cover for long periods of time, maybe a week at at time.
                    > > > It is not in a shed, just covered. One benefit is that it is always
                    > > > close to ambient. However I do wonder if keeping it in the clamps is
                    > > > somehow tweaking things. Before this year, I always took the scope in.
                    > > > Could it be how it is clamped? Is there a chance the CAA got loose?
                    > > > Any other source of potential tilt? Of course, I do not want to rule
                    > > > out the STL-11000 either, so I will take a look at that as well.
                    > > >
                    > > > Any hints?
                    > > >
                    > > > Thanks
                    > > > Tom Carrico
                    > > >
                    > > >
                    > >
                    > >
                    > >
                    > >
                    > >
                    > >
                    > > [Non-text portions of this message have been removed]
                    > >
                    > >
                    > >
                    > >
                    > > Yahoo! Groups Links
                    > >
                    > >
                    > >
                    > >
                    > >
                    > >
                    >
                    >
                    >
                    >
                    >
                    >
                    > [Non-text portions of this message have been removed]
                    >
                    >
                    >
                    >
                    > Yahoo! Groups Links
                    >
                    >
                    >
                    >
                    >
                    >
                  • Mike Shade
                    I have had similar issues with my M300 and tilt but I use a rotator, with the somewhat narrow field of view of this scope it is terribly important to get
                    Message 9 of 11 , Aug 6, 2007
                    • 0 Attachment
                      I have had similar issues with my M300 and tilt but I use a rotator,
                      with the somewhat narrow field of view of this scope it is terribly
                      important to get things flat...an ongoing quest to be sure...

                      At 07:25 AM 8/6/2007, you wrote:

                      >Hi Jim,
                      >Yes, the Feldstein is between the camera and the knurled part and is
                      >very solid. With the Precise Parts adapter, the knurled Tak part and the
                      >Feldstein adapter are replaced by one piece, making it even more secure.
                      >It is easy to believe you did not get perfectly square with the 2" nose
                      >piece.
                      >Go ahead and send the test shot, or post it somewhere that I can look at it.
                      >
                      >Thanks
                      >Tom Carrico
                      >
                      >Jim Miller wrote:
                      > > Thanks Tom. I assume the part with vertical machining is Takahashi, and the
                      > > "knurled" machined part is he feldstein adapter? That looks pretty solid.
                      > > When I did my test shot with the FCT100 I used a 2" nosepiece. looks like I
                      > > need to get a fekdstein adapter and whatever part I will need to attach to
                      > > the FCT100. I have a 10 minute sub of my test shot I can send you. I am
                      > > curious if your results looked the same.
                      > >
                      > > many thanks for the info,
                      > >
                      > > Jim
                      > >
                      > >
                      > > -----Original Message-----
                      > > From:
                      > <mailto:UncensoredTakGroup%40yahoogroups.com>UncensoredTakGroup@yahoogroups.com
                      > > [mailto:UncensoredTakGroup@yahoogroups.com]On Behalf Of Tom Carrico
                      > > Sent: Sunday, August 05, 2007 9:41 PM
                      > > To:
                      > <mailto:UncensoredTakGroup%40yahoogroups.com>UncensoredTakGroup@yahoogroups.com
                      > > Subject: Re: [UncensoredTakGroup] Update - Possible tilt in FSQ
                      > or STL-11000
                      > >
                      > >
                      > > Hi Jim,
                      > > Here is a closeup of one way to attach an STL to an FSQ using the
                      > > Feldstein adapter. I also have a Precise Parts adapter which gets rid of
                      > > one threaded connection, but I do not have a recent image. If you like,
                      > > I can post that tomorrow.
                      > >
                      > >
                      > <http://www.ccdargo.com/tak_feldstein.jpg>http://www.ccdargo.com/tak_feldstein.jpg
                      > >
                      > > Tom Carrico
                      > >
                      > > Jim Miller wrote:
                      > > > Interesting Tom, I missed the earlier thread. I am having that problem
                      > > with
                      > > > an FCT-100 and an 11000. I am cuprous how the camera is attached to the
                      > > OTA.
                      > > > Would this be available in an earlier thread if I looked? Are there any
                      > > > images posted?
                      > > >
                      > > > thanks,
                      > > >
                      > > > Jim
                      > > > -----Original Message-----
                      > > > From:
                      > <mailto:UncensoredTakGroup%40yahoogroups.com>UncensoredTakGroup@yahoogroups.com
                      > > > [mailto:UncensoredTakGroup@yahoogroups.com]On Behalf Of Tom Carrico
                      > > > Sent: Sunday, August 05, 2007 6:59 PM
                      > > > Cc:
                      > <mailto:UncensoredTakGroup%40yahoogroups.com>UncensoredTakGroup@yahoogroups.com;
                      > <mailto:SBIG%40yahoogroups.com>SBIG@yahoogroups.com
                      > > > Subject: [UncensoredTakGroup] Update - Possible tilt in FSQ or STL-11000
                      > > >
                      > > >
                      > > > Hi all,
                      > > > The note at the end of this email describes some issues I was having
                      > > > with my FSQ/STL-11000 system. Many of you responded with great
                      > > > suggestions for getting to the root of the problem. In the last couple
                      > > > weeks I have been trying a number of different configurations and have
                      > > > determined the following:
                      > > >
                      > > > - The STL-11000 appears to be fine. The distortion I see in the corner
                      > > > moves as one would expect as the camera is rotated using the CAA. Also,
                      > > > the distortion happens independent of the filter used (h-alpha, RGB or
                      > > > clear)
                      > > > - There is an optimal rotation angle for best imaging. Imagine standing
                      > > > behind the scope, looking up past the scope. The best possible images,
                      > > > in my setup, occur with the camera oriented so the cables are pointing
                      > > > to the left (in the RA direction). The distortion appears the worst when
                      > > > the camera is rotated such that the cables are pointing towards the
                      > > > ground.
                      > > > - The distortion always improved (image got better), as the scope
                      > > > pointed more towards the zenith.
                      > > > - Keep the focus lock knob loose. This really surprised me. In the past,
                      > > > I had always just barely tightened the knob, figuring that would help
                      > > > make the whole system a bit more rigid. However, apparently it increased
                      > > > the stress, possibly leading to tilt. Now, I make sure it is very loose
                      > > > and rely on the RoboFocus motor to keep the focuser from slipping.
                      > > > - Also discovered that the best focus was achieved by placing the star
                      > > > to be focused about 10-20% out from the center.
                      > > > - I plan on ordering an adapter from Precise Parts that will allow me to
                      > > > keep the focuser racked in. I will update when this arrives.
                      > > >
                      > > > Following all these tips, my images are now very flat, the stars are
                      > > > sharp to the corner and CCDInspector shows a curvature typically < 5%. A
                      > > > huge improvement. So, as I look back and wonder why there was a change
                      > > > for the worst, it seems that I was oriented in the worst possible place
                      > > > and tightening the focus lock too much.
                      > > >
                      > > > I want to thank everyone for their help, it really made a difference in
                      > > > driving this problem to a successful conclusion. The following image of
                      > > > NGC 7822 is the first using the list above. It was taken over the last
                      > > > few nights, with the moon a'glowing, but the air steady.
                      > > >
                      > > >
                      > <http://www.ccdargo.com/ngc7822_fsq_halpha_stl.htm>http://www.ccdargo.com/ngc7822_fsq_halpha_stl.htm
                      > > >
                      > > > I would be interested in everyone's thoughts on this, and if these tips
                      > > > are of any help.
                      > > >
                      > > > Thanks
                      > > > Tom Carrico
                      > > > <http://www.ccdargo.com>http://www.ccdargo.com
                      > > >
                      > > > Tom Carrico wrote:
                      > > > > Hi all,
                      > > > > This is a the note I just sent to Art asking about recent changes in
                      > > > > the behavior of my FSQ/STL-11000. Perhaps one of you has run across
                      > > > > something similar. I can post some images of what I am talking about
                      > > > > if that would help.
                      > > > >
                      > > > > Hi Art,
                      > > > > I have had my FSQ for about 1.5 years. I have been using it with my
                      > > > > STL-11000 with reasonable success, however I have noticed a change.
                      > > > > Earlier in the year, I could take exposures and when using
                      > > > > CCDInspector I would get a curvature of as low as 3%, typically in the
                      > > > > 5-8% range. Stars looked perfect all across the field. This was with
                      > > > > exposures as long as 10 minutes, I rarely go longer. Recently, in the
                      > > > > past 2 months, I cannot reliably get curvature below 10%, and it is
                      > > > > typically 12-15%. The stars are clearly less well focused in one
                      > > > > corner compared to the rest of the image, very easy to see in the
                      > > > > image. I have conducted some experiments where I focus at different
                      > > > > areas of the CCD and there is definitely a sweet spot where the focus
                      > > > > is best, usually about 25% out from the center, but most of the time
                      > > > > this only improves the curvature to around 10% and it is not entirely
                      > > > > reliable..I use a Robofocus to focus. I do not use FocusMax or
                      > > > > anything like that, I sit inside my house and use the RoboFocus
                      > > > > software to manually adjust focus.
                      > > > > The only thing that is different is that I now leave the scope outside
                      > > > > and under a cover for long periods of time, maybe a week at at time.
                      > > > > It is not in a shed, just covered. One benefit is that it is always
                      > > > > close to ambient. However I do wonder if keeping it in the clamps is
                      > > > > somehow tweaking things. Before this year, I always took the scope in.
                      > > > > Could it be how it is clamped? Is there a chance the CAA got loose?
                      > > > > Any other source of potential tilt? Of course, I do not want to rule
                      > > > > out the STL-11000 either, so I will take a look at that as well.
                      > > > >
                      > > > > Any hints?
                      > > > >
                      > > > > Thanks
                      > > > > Tom Carrico
                      > > > >
                      > > > >
                      > > >
                      > > >
                      > > >
                      > > >
                      > > >
                      > > >
                      > > > [Non-text portions of this message have been removed]
                      > > >
                      > > >
                      > > >
                      > > >
                      > > > Yahoo! Groups Links
                      > > >
                      > > >
                      > > >
                      > > >
                      > > >
                      > > >
                      > >
                      > >
                      > >
                      > >
                      > >
                      > >
                      > > [Non-text portions of this message have been removed]
                      > >
                      > >
                      > >
                      > >
                      > > Yahoo! Groups Links
                      > >
                      > >
                      > >
                      > >
                      > >
                      > >
                      >
                      >

                      Mike J. Shade: mshade@...
                      Sonoita Hills Observatory, Sonoita Arizona
                      http://www.sonoitaobservatories.org

                      International Dark Sky Association: www.darksky.org

                      "I like the dark, it's cheap" Ebenezer Scrooge

                      [Non-text portions of this message have been removed]
                    • Jim Miller
                      Thanks Tom, I will post one tonight when I get back home. best regards, Jim ... From: UncensoredTakGroup@yahoogroups.com
                      Message 10 of 11 , Aug 7, 2007
                      • 0 Attachment
                        Thanks Tom, I will post one tonight when I get back home.

                        best regards,

                        Jim
                        -----Original Message-----
                        From: UncensoredTakGroup@yahoogroups.com
                        [mailto:UncensoredTakGroup@yahoogroups.com]On Behalf Of Tom Carrico
                        Sent: Monday, August 06, 2007 8:25 AM
                        To: UncensoredTakGroup@yahoogroups.com
                        Subject: Re: [UncensoredTakGroup] Update - Possible tilt in FSQ or
                        STL-11000


                        Hi Jim,
                        Yes, the Feldstein is between the camera and the knurled part and is
                        very solid. With the Precise Parts adapter, the knurled Tak part and the
                        Feldstein adapter are replaced by one piece, making it even more secure.
                        It is easy to believe you did not get perfectly square with the 2" nose
                        piece.
                        Go ahead and send the test shot, or post it somewhere that I can look at
                        it.

                        Thanks
                        Tom Carrico

                        Jim Miller wrote:
                        > Thanks Tom. I assume the part with vertical machining is Takahashi, and
                        the
                        > "knurled" machined part is he feldstein adapter? That looks pretty
                        solid.
                        > When I did my test shot with the FCT100 I used a 2" nosepiece. looks
                        like I
                        > need to get a fekdstein adapter and whatever part I will need to attach
                        to
                        > the FCT100. I have a 10 minute sub of my test shot I can send you. I am
                        > curious if your results looked the same.
                        >
                        > many thanks for the info,
                        >
                        > Jim
                        >
                        >
                        > -----Original Message-----
                        > From: UncensoredTakGroup@yahoogroups.com
                        > [mailto:UncensoredTakGroup@yahoogroups.com]On Behalf Of Tom Carrico
                        > Sent: Sunday, August 05, 2007 9:41 PM
                        > To: UncensoredTakGroup@yahoogroups.com
                        > Subject: Re: [UncensoredTakGroup] Update - Possible tilt in FSQ or
                        STL-11000
                        >
                        >
                        > Hi Jim,
                        > Here is a closeup of one way to attach an STL to an FSQ using the
                        > Feldstein adapter. I also have a Precise Parts adapter which gets rid of
                        > one threaded connection, but I do not have a recent image. If you like,
                        > I can post that tomorrow.
                        >
                        > http://www.ccdargo.com/tak_feldstein.jpg
                        >
                        > Tom Carrico
                        >
                        > Jim Miller wrote:
                        > > Interesting Tom, I missed the earlier thread. I am having that problem
                        > with
                        > > an FCT-100 and an 11000. I am cuprous how the camera is attached to
                        the
                        > OTA.
                        > > Would this be available in an earlier thread if I looked? Are there
                        any
                        > > images posted?
                        > >
                        > > thanks,
                        > >
                        > > Jim
                        > > -----Original Message-----
                        > > From: UncensoredTakGroup@yahoogroups.com
                        > > [mailto:UncensoredTakGroup@yahoogroups.com]On Behalf Of Tom Carrico
                        > > Sent: Sunday, August 05, 2007 6:59 PM
                        > > Cc: UncensoredTakGroup@yahoogroups.com; SBIG@yahoogroups.com
                        > > Subject: [UncensoredTakGroup] Update - Possible tilt in FSQ or
                        STL-11000
                        > >
                        > >
                        > > Hi all,
                        > > The note at the end of this email describes some issues I was having
                        > > with my FSQ/STL-11000 system. Many of you responded with great
                        > > suggestions for getting to the root of the problem. In the last couple
                        > > weeks I have been trying a number of different configurations and have
                        > > determined the following:
                        > >
                        > > - The STL-11000 appears to be fine. The distortion I see in the corner
                        > > moves as one would expect as the camera is rotated using the CAA.
                        Also,
                        > > the distortion happens independent of the filter used (h-alpha, RGB or
                        > > clear)
                        > > - There is an optimal rotation angle for best imaging. Imagine
                        standing
                        > > behind the scope, looking up past the scope. The best possible images,
                        > > in my setup, occur with the camera oriented so the cables are pointing
                        > > to the left (in the RA direction). The distortion appears the worst
                        when
                        > > the camera is rotated such that the cables are pointing towards the
                        > > ground.
                        > > - The distortion always improved (image got better), as the scope
                        > > pointed more towards the zenith.
                        > > - Keep the focus lock knob loose. This really surprised me. In the
                        past,
                        > > I had always just barely tightened the knob, figuring that would help
                        > > make the whole system a bit more rigid. However, apparently it
                        increased
                        > > the stress, possibly leading to tilt. Now, I make sure it is very
                        loose
                        > > and rely on the RoboFocus motor to keep the focuser from slipping.
                        > > - Also discovered that the best focus was achieved by placing the star
                        > > to be focused about 10-20% out from the center.
                        > > - I plan on ordering an adapter from Precise Parts that will allow me
                        to
                        > > keep the focuser racked in. I will update when this arrives.
                        > >
                        > > Following all these tips, my images are now very flat, the stars are
                        > > sharp to the corner and CCDInspector shows a curvature typically < 5%.
                        A
                        > > huge improvement. So, as I look back and wonder why there was a change
                        > > for the worst, it seems that I was oriented in the worst possible
                        place
                        > > and tightening the focus lock too much.
                        > >
                        > > I want to thank everyone for their help, it really made a difference
                        in
                        > > driving this problem to a successful conclusion. The following image
                        of
                        > > NGC 7822 is the first using the list above. It was taken over the last
                        > > few nights, with the moon a'glowing, but the air steady.
                        > >
                        > > http://www.ccdargo.com/ngc7822_fsq_halpha_stl.htm
                        > >
                        > > I would be interested in everyone's thoughts on this, and if these
                        tips
                        > > are of any help.
                        > >
                        > > Thanks
                        > > Tom Carrico
                        > > http://www.ccdargo.com
                        > >
                        > > Tom Carrico wrote:
                        > > > Hi all,
                        > > > This is a the note I just sent to Art asking about recent changes in
                        > > > the behavior of my FSQ/STL-11000. Perhaps one of you has run across
                        > > > something similar. I can post some images of what I am talking about
                        > > > if that would help.
                        > > >
                        > > > Hi Art,
                        > > > I have had my FSQ for about 1.5 years. I have been using it with my
                        > > > STL-11000 with reasonable success, however I have noticed a change.
                        > > > Earlier in the year, I could take exposures and when using
                        > > > CCDInspector I would get a curvature of as low as 3%, typically in
                        the
                        > > > 5-8% range. Stars looked perfect all across the field. This was with
                        > > > exposures as long as 10 minutes, I rarely go longer. Recently, in
                        the
                        > > > past 2 months, I cannot reliably get curvature below 10%, and it is
                        > > > typically 12-15%. The stars are clearly less well focused in one
                        > > > corner compared to the rest of the image, very easy to see in the
                        > > > image. I have conducted some experiments where I focus at different
                        > > > areas of the CCD and there is definitely a sweet spot where the
                        focus
                        > > > is best, usually about 25% out from the center, but most of the time
                        > > > this only improves the curvature to around 10% and it is not
                        entirely
                        > > > reliable..I use a Robofocus to focus. I do not use FocusMax or
                        > > > anything like that, I sit inside my house and use the RoboFocus
                        > > > software to manually adjust focus.
                        > > > The only thing that is different is that I now leave the scope
                        outside
                        > > > and under a cover for long periods of time, maybe a week at at time.
                        > > > It is not in a shed, just covered. One benefit is that it is always
                        > > > close to ambient. However I do wonder if keeping it in the clamps is
                        > > > somehow tweaking things. Before this year, I always took the scope
                        in.
                        > > > Could it be how it is clamped? Is there a chance the CAA got loose?
                        > > > Any other source of potential tilt? Of course, I do not want to rule
                        > > > out the STL-11000 either, so I will take a look at that as well.
                        > > >
                        > > > Any hints?
                        > > >
                        > > > Thanks
                        > > > Tom Carrico
                        > > >
                        > > >
                        > >
                        > >
                        > >
                        > >
                        > >
                        > >
                        > > [Non-text portions of this message have been removed]
                        > >
                        > >
                        > >
                        > >
                        > > Yahoo! Groups Links
                        > >
                        > >
                        > >
                        > >
                        > >
                        > >
                        >
                        >
                        >
                        >
                        >
                        >
                        > [Non-text portions of this message have been removed]
                        >
                        >
                        >
                        >
                        > Yahoo! Groups Links
                        >
                        >
                        >
                        >
                        >
                        >






                        [Non-text portions of this message have been removed]
                      • Jim Miller
                        Tom, I am still traveling, but this gentlemen s (see below) image exhibits the exact same problem as mine. I will still post mine when I get back in town.
                        Message 11 of 11 , Aug 10, 2007
                        • 0 Attachment
                          Tom, I am still traveling, but this gentlemen's (see below) image exhibits
                          the exact same problem as mine. I will still post mine when I get back in
                          town.

                          again, thanks for the info,

                          Jim

                          Hi all,

                          I am new to the group but have been imaging for some time. I have just
                          obtained an FCT 100 which I am using with an Artemis 11002 full frame
                          camera. The photo of NGC 7000 in the photos section under Den's Astro
                          shows the problem I have. It is almost a goldfish bowl effect with all
                          four corners showing considerable distortion of the stars. The centre
                          of the picture is 'Tak sharp'. Can anybody help with this please, do I
                          need to lengthen the flattener to chip distance or shorten it.

                          TIA

                          Dennis



                          -----Original Message-----
                          From: UncensoredTakGroup@yahoogroups.com
                          [mailto:UncensoredTakGroup@yahoogroups.com]On Behalf Of Tom Carrico
                          Sent: Monday, August 06, 2007 8:25 AM
                          To: UncensoredTakGroup@yahoogroups.com
                          Subject: Re: [UncensoredTakGroup] Update - Possible tilt in FSQ or STL-11000


                          Hi Jim,
                          Yes, the Feldstein is between the camera and the knurled part and is
                          very solid. With the Precise Parts adapter, the knurled Tak part and the
                          Feldstein adapter are replaced by one piece, making it even more secure.
                          It is easy to believe you did not get perfectly square with the 2" nose
                          piece.
                          Go ahead and send the test shot, or post it somewhere that I can look at
                          it.

                          Thanks
                          Tom Carrico

                          Jim Miller wrote:
                          > Thanks Tom. I assume the part with vertical machining is Takahashi, and
                          the
                          > "knurled" machined part is he feldstein adapter? That looks pretty
                          solid.
                          > When I did my test shot with the FCT100 I used a 2" nosepiece. looks
                          like I
                          > need to get a fekdstein adapter and whatever part I will need to attach
                          to
                          > the FCT100. I have a 10 minute sub of my test shot I can send you. I am
                          > curious if your results looked the same.
                          >
                          > many thanks for the info,
                          >
                          > Jim
                          >
                          >
                          > -----Original Message-----
                          > From: UncensoredTakGroup@yahoogroups.com
                          > [mailto:UncensoredTakGroup@yahoogroups.com]On Behalf Of Tom Carrico
                          > Sent: Sunday, August 05, 2007 9:41 PM
                          > To: UncensoredTakGroup@yahoogroups.com
                          > Subject: Re: [UncensoredTakGroup] Update - Possible tilt in FSQ or
                          STL-11000
                          >
                          >
                          > Hi Jim,
                          > Here is a closeup of one way to attach an STL to an FSQ using the
                          > Feldstein adapter. I also have a Precise Parts adapter which gets rid of
                          > one threaded connection, but I do not have a recent image. If you like,
                          > I can post that tomorrow.
                          >
                          > http://www.ccdargo.com/tak_feldstein.jpg
                          >
                          > Tom Carrico
                          >
                          > Jim Miller wrote:
                          > > Interesting Tom, I missed the earlier thread. I am having that problem
                          > with
                          > > an FCT-100 and an 11000. I am cuprous how the camera is attached to
                          the
                          > OTA.
                          > > Would this be available in an earlier thread if I looked? Are there
                          any
                          > > images posted?
                          > >
                          > > thanks,
                          > >
                          > > Jim
                          > > -----Original Message-----
                          > > From: UncensoredTakGroup@yahoogroups.com
                          > > [mailto:UncensoredTakGroup@yahoogroups.com]On Behalf Of Tom Carrico
                          > > Sent: Sunday, August 05, 2007 6:59 PM
                          > > Cc: UncensoredTakGroup@yahoogroups.com; SBIG@yahoogroups.com
                          > > Subject: [UncensoredTakGroup] Update - Possible tilt in FSQ or
                          STL-11000
                          > >
                          > >
                          > > Hi all,
                          > > The note at the end of this email describes some issues I was having
                          > > with my FSQ/STL-11000 system. Many of you responded with great
                          > > suggestions for getting to the root of the problem. In the last couple
                          > > weeks I have been trying a number of different configurations and have
                          > > determined the following:
                          > >
                          > > - The STL-11000 appears to be fine. The distortion I see in the corner
                          > > moves as one would expect as the camera is rotated using the CAA.
                          Also,
                          > > the distortion happens independent of the filter used (h-alpha, RGB or
                          > > clear)
                          > > - There is an optimal rotation angle for best imaging. Imagine
                          standing
                          > > behind the scope, looking up past the scope. The best possible images,
                          > > in my setup, occur with the camera oriented so the cables are pointing
                          > > to the left (in the RA direction). The distortion appears the worst
                          when
                          > > the camera is rotated such that the cables are pointing towards the
                          > > ground.
                          > > - The distortion always improved (image got better), as the scope
                          > > pointed more towards the zenith.
                          > > - Keep the focus lock knob loose. This really surprised me. In the
                          past,
                          > > I had always just barely tightened the knob, figuring that would help
                          > > make the whole system a bit more rigid. However, apparently it
                          increased
                          > > the stress, possibly leading to tilt. Now, I make sure it is very
                          loose
                          > > and rely on the RoboFocus motor to keep the focuser from slipping.
                          > > - Also discovered that the best focus was achieved by placing the star
                          > > to be focused about 10-20% out from the center.
                          > > - I plan on ordering an adapter from Precise Parts that will allow me
                          to
                          > > keep the focuser racked in. I will update when this arrives.
                          > >
                          > > Following all these tips, my images are now very flat, the stars are
                          > > sharp to the corner and CCDInspector shows a curvature typically < 5%.
                          A
                          > > huge improvement. So, as I look back and wonder why there was a change
                          > > for the worst, it seems that I was oriented in the worst possible
                          place
                          > > and tightening the focus lock too much.
                          > >
                          > > I want to thank everyone for their help, it really made a difference
                          in
                          > > driving this problem to a successful conclusion. The following image
                          of
                          > > NGC 7822 is the first using the list above. It was taken over the last
                          > > few nights, with the moon a'glowing, but the air steady.
                          > >
                          > > http://www.ccdargo.com/ngc7822_fsq_halpha_stl.htm
                          > >
                          > > I would be interested in everyone's thoughts on this, and if these
                          tips
                          > > are of any help.
                          > >
                          > > Thanks
                          > > Tom Carrico
                          > > http://www.ccdargo.com
                          > >
                          > > Tom Carrico wrote:
                          > > > Hi all,
                          > > > This is a the note I just sent to Art asking about recent changes in
                          > > > the behavior of my FSQ/STL-11000. Perhaps one of you has run across
                          > > > something similar. I can post some images of what I am talking about
                          > > > if that would help.
                          > > >
                          > > > Hi Art,
                          > > > I have had my FSQ for about 1.5 years. I have been using it with my
                          > > > STL-11000 with reasonable success, however I have noticed a change.
                          > > > Earlier in the year, I could take exposures and when using
                          > > > CCDInspector I would get a curvature of as low as 3%, typically in
                          the
                          > > > 5-8% range. Stars looked perfect all across the field. This was with
                          > > > exposures as long as 10 minutes, I rarely go longer. Recently, in
                          the
                          > > > past 2 months, I cannot reliably get curvature below 10%, and it is
                          > > > typically 12-15%. The stars are clearly less well focused in one
                          > > > corner compared to the rest of the image, very easy to see in the
                          > > > image. I have conducted some experiments where I focus at different
                          > > > areas of the CCD and there is definitely a sweet spot where the
                          focus
                          > > > is best, usually about 25% out from the center, but most of the time
                          > > > this only improves the curvature to around 10% and it is not
                          entirely
                          > > > reliable..I use a Robofocus to focus. I do not use FocusMax or
                          > > > anything like that, I sit inside my house and use the RoboFocus
                          > > > software to manually adjust focus.
                          > > > The only thing that is different is that I now leave the scope
                          outside
                          > > > and under a cover for long periods of time, maybe a week at at time.
                          > > > It is not in a shed, just covered. One benefit is that it is always
                          > > > close to ambient. However I do wonder if keeping it in the clamps is
                          > > > somehow tweaking things. Before this year, I always took the scope
                          in.
                          > > > Could it be how it is clamped? Is there a chance the CAA got loose?
                          > > > Any other source of potential tilt? Of course, I do not want to rule
                          > > > out the STL-11000 either, so I will take a look at that as well.
                          > > >
                          > > > Any hints?
                          > > >
                          > > > Thanks
                          > > > Tom Carrico
                          > > >
                          > > >
                          > >
                          > >
                          > >
                          > >
                          > >
                          > >
                          > > [Non-text portions of this message have been removed]
                          > >
                          > >
                          > >
                          > >
                          > > Yahoo! Groups Links
                          > >
                          > >
                          > >
                          > >
                          > >
                          > >
                          >
                          >
                          >
                          >
                          >
                          >
                          > [Non-text portions of this message have been removed]
                          >
                          >
                          >
                          >
                          > Yahoo! Groups Links
                          >
                          >
                          >
                          >
                          >
                          >






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