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Advice Please?

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  • mpastro2001
    Hi all Not sure where I should post this message, so I will start here as a good bet where I can get some good advice. I use a Paramount ME with a 12.5
    Message 1 of 3 , Apr 8, 2007
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      Hi all

      Not sure where I should post this message, so I will start here as a
      good bet where I can get some good advice.

      I use a Paramount ME with a 12.5" RCOS/STL11K, image scale 0.65asp.

      Up until last night, I could take unguided images upto 8 minutes or
      so in duration and have round stars (PROTRACK/PEC enabled). Last
      night, right from start up, I started to experience star elongation
      (in RA only) after 30 seconds.......to the extent that it would
      suggest my mount had lost polar alignment.

      Things I have checked/done:
      PROTRACK disabled, PEC disabled.
      cable management
      polar alignment (I centered a star at Dec 0, put the crosshair on,
      and took an image at 10 second intervals over 12 minutes...drift was
      4 pixels in one axis and 2 pixels in the other..image scale is
      0.65asp.)

      I spent several hours trying to fault find this, to no avail, and I
      certainly havent seen this behaviour before.

      So, what additional checks could I undertake please?

      tks

      Martin
    • sforster12
      How s your collimation? My Tak has elongated stars due to mis-collimation, not polar alignment. STU ... a ... was
      Message 2 of 3 , Apr 8, 2007
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        How's your collimation?

        My Tak has elongated stars due to mis-collimation, not polar
        alignment.

        STU

        --- In ccd-newastro@yahoogroups.com, "mpastro2001" <mpastro2001@...>
        wrote:
        >
        > Hi all
        >
        > Not sure where I should post this message, so I will start here as
        a
        > good bet where I can get some good advice.
        >
        > I use a Paramount ME with a 12.5" RCOS/STL11K, image scale 0.65asp.
        >
        > Up until last night, I could take unguided images upto 8 minutes or
        > so in duration and have round stars (PROTRACK/PEC enabled). Last
        > night, right from start up, I started to experience star elongation
        > (in RA only) after 30 seconds.......to the extent that it would
        > suggest my mount had lost polar alignment.
        >
        > Things I have checked/done:
        > PROTRACK disabled, PEC disabled.
        > cable management
        > polar alignment (I centered a star at Dec 0, put the crosshair on,
        > and took an image at 10 second intervals over 12 minutes...drift
        was
        > 4 pixels in one axis and 2 pixels in the other..image scale is
        > 0.65asp.)
        >
        > I spent several hours trying to fault find this, to no avail, and I
        > certainly havent seen this behaviour before.
        >
        > So, what additional checks could I undertake please?
        >
        > tks
        >
        > Martin
        >
      • maxmsm
        Maybe check the focuser, ota rings and scope to mount bolts. Loose secondary? Perhap it is not the mount at all Max ... a ... or ... elongation ... was ... I
        Message 3 of 3 , Apr 8, 2007
        • 0 Attachment
          Maybe check the focuser, ota rings and scope to mount bolts. Loose
          secondary?
          Perhap it is not the mount at all

          Max

          --- In ccd-newastro@yahoogroups.com, "mpastro2001" <mpastro2001@...>
          wrote:
          >
          > Hi all
          >
          > Not sure where I should post this message, so I will start here as
          a
          > good bet where I can get some good advice.
          >
          > I use a Paramount ME with a 12.5" RCOS/STL11K, image scale 0.65asp.
          >
          > Up until last night, I could take unguided images upto 8 minutes
          or
          > so in duration and have round stars (PROTRACK/PEC enabled). Last
          > night, right from start up, I started to experience star
          elongation
          > (in RA only) after 30 seconds.......to the extent that it would
          > suggest my mount had lost polar alignment.
          >
          > Things I have checked/done:
          > PROTRACK disabled, PEC disabled.
          > cable management
          > polar alignment (I centered a star at Dec 0, put the crosshair on,
          > and took an image at 10 second intervals over 12 minutes...drift
          was
          > 4 pixels in one axis and 2 pixels in the other..image scale is
          > 0.65asp.)
          >
          > I spent several hours trying to fault find this, to no avail, and
          I
          > certainly havent seen this behaviour before.
          >
          > So, what additional checks could I undertake please?
          >
          > tks
          >
          > Martin
          >
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