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Focuser problem or not?

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  • franslalleman
    Hi all, need some assistance here, yesterday grabbed NGC 7000 with the FLT 98 CF and a full frame ccd camera(SXVR H35). I guided with a dsi and PHD,during
    Message 1 of 3 , Sep 27, 2010
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      Hi all,
      need some assistance here,
      yesterday grabbed NGC 7000 with the FLT 98 CF and a full frame ccd camera(SXVR H35).
      I guided with a dsi and PHD,during guiding I watched the graph tool and the guiding error wasn't bigger then 1 pixel.(which is fine I believe)
      I made 4 15 min subs.
      I wasn't happy with the result at all.
      see my result here..

      http://www.sterrenwacht-wave.nl/ngc_7000_bf.htm

      Today I checked what could have gone wrong and notiched the focuser had a bit flexure.
      I removed the plastic srews that holds the focuser in his place and replaced them by steel ones.
      MY QUESTION IS NOW,
      is the fault you see on my image the result of a bad focuser?
      If yes can anyone tell me what to do ?

      thx in advance
      Frans Lalleman
      www.sterrenwacht-wave.nl
    • Jean-Marie Locci
      Hi Frans. You are right to suspect flexure if you say that guiding went fine. You can plot in Excel the flexure happening between shots, even if you haven t
      Message 2 of 3 , Sep 27, 2010
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        Hi Frans.

         

        You are right to suspect flexure if you say that guiding went fine. You can plot in Excel the flexure happening between shots, even if you haven’t too many of then, using DeepSkyStacker and you will get the flexure in RA and DEC. It will then tell you what happened during the 15 min exposure and you will be able to relate the direction of the elongation of your stars with the flexure measurements.

         

        There is a tutorial to measure flexure with DSS at http://deepskystacker.wikispaces.com/Measuring+differential+flexure

         

        All the best.

         

        Jean-Marie, Perth , Australia .

         


        From: William-Optics@yahoogroups.com [mailto: William-Optics@yahoogroups.com ] On Behalf Of franslalleman
        Sent: Monday, 27 September 2010 5:24 PM
        To: William-Optics@yahoogroups.com
        Subject: [William Optics] Focuser problem or not?

         

         

        Hi all,
        need some assistance here,
        yesterday grabbed NGC 7000 with the FLT 98 CF and a full frame ccd camera(SXVR H35).
        I guided with a dsi and PHD,during guiding I watched the graph tool and the guiding error wasn't bigger then 1 pixel.(which is fine I believe)
        I made 4 15 min subs.
        I wasn't happy with the result at all.
        see my result here..

        http://www.sterrenwacht-wave.nl/ngc_7000_bf.htm

        Today I checked what could have gone wrong and notiched the focuser had a bit flexure.
        I removed the plastic srews that holds the focuser in his place and replaced them by steel ones.
        MY QUESTION IS NOW,
        is the fault you see on my image the result of a bad focuser?
        If yes can anyone tell me what to do ?

        thx in advance
        Frans Lalleman
        www.sterrenwacht-wave.nl

         
        The contents of this e-mail, including any attachments are the property of INPEX, are intended for use by the ordinary user of the e-mail address to which it was addressed and may also be privileged. If you are not the addressee of this e-mail you may not copy, forward, disclose or otherwise use it or any part of it in any form whatsoever. If you have received this e-mail in error please e-mail the sender by replying to this message. Emails sent or received may be monitored to ensure compliance with the law, regulation and/or INPEX policies.
         
         
        Please note: INPEX Perth Office has relocated to Level 22, 100 St Georges Terrace Perth WA 6000. Ph: (08) 6213 6000
         
        The contents of this e-mail, including any attachments are the property of INPEX, are intended for use by the ordinary user of the e-mail address to which it was addressed and may also be privileged. If you are not the addressee of this e-mail you may not copy, forward, disclose or otherwise use it or any part of it in any form whatsoever. If you have received this e-mail in error please e-mail the sender by replying to this message. Emails sent or received may be monitored to ensure compliance with the law, regulation and/or INPEX policies.
         
         
        Please note: INPEX Perth Office has relocated to Level 22, 100 St Georges Terrace Perth WA 6000. Ph: (08) 6213 6000
      • Frans Lalleman
        Thx, Jean, I will try your suggestions. Again thx for your time and will let you know how it ends. Greetings from holland Frans Verzonden vanaf mijn
        Message 3 of 3 , Sep 28, 2010
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          Thx, Jean,
          I will try your suggestions.
          Again thx for your time and will let you know how it ends.
          Greetings from holland
          Frans

          Verzonden vanaf mijn BlackBerry®-toestel


          From: "Jean-Marie Locci" <jean-marie.locci@...>
          Sender: William-Optics@yahoogroups.com
          Date: Tue, 28 Sep 2010 10:24:26 +0800
          To: <William-Optics@yahoogroups.com>
          ReplyTo: William-Optics@yahoogroups.com
          Subject: RE: [William Optics] Focuser problem or not?

           

          Hi Frans.

           

          You are right to suspect flexure if you say that guiding went fine. You can plot in Excel the flexure happening between shots, even if you haven’t too many of then, using DeepSkyStacker and you will get the flexure in RA and DEC. It will then tell you what happened during the 15 min exposure and you will be able to relate the direction of the elongation of your stars with the flexure measurements.

           

          There is a tutorial to measure flexure with DSS at http://deepskystacker.wikispaces.com/Measuring+differential+flexure

           

          All the best.

           

          Jean-Marie, Perth , Australia .

           


          From: William-Optics@yahoogroups.com [mailto: William-Optics@yahoogroups.com ] On Behalf Of franslalleman
          Sent: Monday, 27 September 2010 5:24 PM
          To: William-Optics@yahoogroups.com
          Subject: [William Optics] Focuser problem or not?

           

           

          Hi all,
          need some assistance here,
          yesterday grabbed NGC 7000 with the FLT 98 CF and a full frame ccd camera(SXVR H35).
          I guided with a dsi and PHD,during guiding I watched the graph tool and the guiding error wasn't bigger then 1 pixel.(which is fine I believe)
          I made 4 15 min subs.
          I wasn't happy with the result at all.
          see my result here..

          http://www.sterrenwacht-wave.nl/ngc_7000_bf.htm

          Today I checked what could have gone wrong and notiched the focuser had a bit flexure.
          I removed the plastic srews that holds the focuser in his place and replaced them by steel ones.
          MY QUESTION IS NOW,
          is the fault you see on my image the result of a bad focuser?
          If yes can anyone tell me what to do ?

          thx in advance
          Frans Lalleman
          www.sterrenwacht-wave.nl

           
          The contents of this e-mail, including any attachments are the property of INPEX, are intended for use by the ordinary user of the e-mail address to which it was addressed and may also be privileged. If you are not the addressee of this e-mail you may not copy, forward, disclose or otherwise use it or any part of it in any form whatsoever. If you have received this e-mail in error please e-mail the sender by replying to this message. Emails sent or received may be monitored to ensure compliance with the law, regulation and/or INPEX policies.
           
           
          Please note: INPEX Perth Office has relocated to Level 22, 100 St Georges Terrace Perth WA 6000. Ph: (08) 6213 6000
           
          The contents of this e-mail, including any attachments are the property of INPEX, are intended for use by the ordinary user of the e-mail address to which it was addressed and may also be privileged. If you are not the addressee of this e-mail you may not copy, forward, disclose or otherwise use it or any part of it in any form whatsoever. If you have received this e-mail in error please e-mail the sender by replying to this message. Emails sent or received may be monitored to ensure compliance with the law, regulation and/or INPEX policies.
           
           
          Please note: INPEX Perth Office has relocated to Level 22, 100 St Georges Terrace Perth WA 6000. Ph: (08) 6213 6000
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