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  • Focus
    Hey guys, I took this last night with an ap 1200 mount. I took an ok 60 second guided shot and then tried guiding, focal length 1600mm. I used .5 guiding and
    Message 1 of 8 , Jun 19, 2000
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      Hey guys,
      I took this last night with an ap 1200 mount.  I took an ok 60 second guided shot and then tried guiding, focal length 1600mm.  I used .5 guiding and calibrated at .5x.  When I did the star stayed on the little autoguiding chip the whole exposure.  I did not play with backlash at all.  I used a bunch of different settings on maxim guiding, but didn't try to change backlash in guider settings. 
      I even tried the Roland calibrate at 1x and guide at .5x trick and got the same results. 
      I think it is dec backlash, can anyone help?  The ap mount manual says to depress one dip switch at a time till backlash gone.  I was too tuckered out to mess with it. 
      thanks
      Brian
    • Ron Wodaski
      If you are using Maxim, you can check your backlash settings using the software. Position yourself at a star near the celestial equator, so that movement in
      Message 2 of 8 , Jun 19, 2000
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        If you are using Maxim, you can check your backlash settings using the software. Position yourself at a star near the celestial equator, so that movement in Dec and RA will be similar.
         
        When the Guide tab is active, note that there is a button labeled Move. Click this button to open a Move dialog. Make sure the mount is set to move at your guide rate (typically .5x). You have a fairly long focal length, 1600mm, so I would suggest that you try a move duration of 5 seconds.
         
        Click the +X button to get things started. Ignore the amount of movement. Note the position of a bright star. .
         
        Now click -X, note the position, and then click +X again. Does the star return to the same position as it was in before? In other words, are the movements the same amount?
         
        Now do the same process for Y. Is the magnitude of the movement the same, larger, smaller? The two directions should move close to the same amount. If not, it's likely that you have a problem with backlash settings. A little experimentation should confirm whether you have too little, or too much backlash. The Guide Settings dialog allows you to use software backlash adjustments, and you can observe the results of these changes in order to determine how your backlash settings are.
         
        You can also check your backlash visually; the AP manual has good instructions for doing this. Be patient with the process; it takes a bit of time to get a feel for what is best. You definitely are better off having too little backlash compensation, because you can do additional compensation in the software settings. If you have too much, it will cause results like you already have seen. <g>
         
        Other factors that might contribute to the duplicate star images:
         
        * A too-perfectly balanced mount. You want a little excess weight on the east side of the mount, to keep the gears always meshed and pushing "up hill."
         
        * Too high of an aggressiveness setting. This can push the mount harder than it needs to be pushed, or cause the mount to overreact to twinkling of stars.
         
        * To long of a maximum duration of movement; try cutting this down.
         
        But backlash is the usually culprit; it sounds like you have too much.
         
        Ron Wodaski
        -----Original Message-----
        From: Focus [mailto:focus@...]
        Sent: Monday, June 19, 2000 10:26 AM
        To: ccd-newastro@egroups.com
        Subject: [ccd-newastro]

        Hey guys,
        I took this last night with an ap 1200 mount.  I took an ok 60 second guided shot and then tried guiding, focal length 1600mm.  I used .5 guiding and calibrated at .5x.  When I did the star stayed on the little autoguiding chip the whole exposure.  I did not play with backlash at all.  I used a bunch of different settings on maxim guiding, but didn't try to change backlash in guider settings. 
        I even tried the Roland calibrate at 1x and guide at .5x trick and got the same results. 
        I think it is dec backlash, can anyone help?  The ap mount manual says to depress one dip switch at a time till backlash gone.  I was too tuckered out to mess with it. 
        thanks
        Brian


      • Ron Wodaski
        One other idea -- how long was your guide exposure? Sometimes, you can eliminate this kind of oscillation simply by going to a longer guide exposure. I
        Message 3 of 8 , Jun 19, 2000
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          One other idea -- how long was your guide exposure? Sometimes, you can eliminate this kind of oscillation simply by going to a longer guide exposure. I typically use guide exposures of around 4-5 seconds.
           
          Ron Wodaski
          -----Original Message-----
          From: Focus [mailto:focus@...]
          Sent: Monday, June 19, 2000 10:26 AM
          To: ccd-newastro@egroups.com
          Subject: [ccd-newastro]

          Hey guys,
          I took this last night with an ap 1200 mount.  I took an ok 60 second guided shot and then tried guiding, focal length 1600mm.  I used .5 guiding and calibrated at .5x.  When I did the star stayed on the little autoguiding chip the whole exposure.  I did not play with backlash at all.  I used a bunch of different settings on maxim guiding, but didn't try to change backlash in guider settings. 
          I even tried the Roland calibrate at 1x and guide at .5x trick and got the same results. 
          I think it is dec backlash, can anyone help?  The ap mount manual says to depress one dip switch at a time till backlash gone.  I was too tuckered out to mess with it. 
          thanks
          Brian


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          ccd-newastro-unsubscribe@egroups.com


        • Focus
          Hi Ron, Thanks for the invaluable tips. I was so frustrated man o man. Wanna come out here for a night or two? I got lots of mounts and scopes and
          Message 4 of 8 , Jun 19, 2000
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            Hi Ron,
             
            Thanks for the invaluable tips.  I was so frustrated man o man.  Wanna come out here for a night or two?  I got lots of mounts and scopes and cameras......
             
            Are the Maxim backlash settings the same thing as using the backlash settings on the mount?  I haven't reset those. 
             
            I have the 400 goto moutn set as you did in AZ, should I do this also for the 1200 or just buy a Paramount 1100?  <g>
             
            I trust you still like the njp, I got hold of one and will be using it as my dark site mount.  Are you just going through gear for the book or really trying to find good stuff?  What happened with the gpdx? I printed your web page and am reading it tonight about that mount.  I think my 400 is in the launch position....
             
            take care and let's start this group rolling, huh?
            Brian
            ----- Original Message -----
            Sent: Monday, June 19, 2000 4:39 PM
            Subject: RE: [ccd-newastro]

            If you are using Maxim, you can check your backlash settings using the software. Position yourself at a star near the celestial equator, so that movement in Dec and RA will be similar.
             
            When the Guide tab is active, note that there is a button labeled Move. Click this button to open a Move dialog. Make sure the mount is set to move at your guide rate (typically .5x). You have a fairly long focal length, 1600mm, so I would suggest that you try a move duration of 5 seconds.
             
            Click the +X button to get things started. Ignore the amount of movement. Note the position of a bright star. .
             
            Now click -X, note the position, and then click +X again. Does the star return to the same position as it was in before? In other words, are the movements the same amount?
             
            Now do the same process for Y. Is the magnitude of the movement the same, larger, smaller? The two directions should move close to the same amount. If not, it's likely that you have a problem with backlash settings. A little experimentation should confirm whether you have too little, or too much backlash. The Guide Settings dialog allows you to use software backlash adjustments, and you can observe the results of these changes in order to determine how your backlash settings are.
             
            You can also check your backlash visually; the AP manual has good instructions for doing this. Be patient with the process; it takes a bit of time to get a feel for what is best. You definitely are better off having too little backlash compensation, because you can do additional compensation in the software settings. If you have too much, it will cause results like you already have seen. <g>
             
            Other factors that might contribute to the duplicate star images:
             
            * A too-perfectly balanced mount. You want a little excess weight on the east side of the mount, to keep the gears always meshed and pushing "up hill."
             
            * Too high of an aggressiveness setting. This can push the mount harder than it needs to be pushed, or cause the mount to overreact to twinkling of stars.
             
            * To long of a maximum duration of movement; try cutting this down.
             
            But backlash is the usually culprit; it sounds like you have too much.
             
            Ron Wodaski
            -----Original Message-----
            From: Focus [mailto:focus@...]
            Sent: Monday, June 19, 2000 10:26 AM
            To: ccd-newastro@egroups.com
            Subject: [ccd-newastro]

            Hey guys,
            I took this last night with an ap 1200 mount.  I took an ok 60 second guided shot and then tried guiding, focal length 1600mm.  I used .5 guiding and calibrated at .5x.  When I did the star stayed on the little autoguiding chip the whole exposure.  I did not play with backlash at all.  I used a bunch of different settings on maxim guiding, but didn't try to change backlash in guider settings. 
            I even tried the Roland calibrate at 1x and guide at .5x trick and got the same results. 
            I think it is dec backlash, can anyone help?  The ap mount manual says to depress one dip switch at a time till backlash gone.  I was too tuckered out to mess with it. 
            thanks
            Brian



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            ccd-newastro-unsubscribe@egroups.com


          • Focus
            I was using 3-4 seconds then 5-7 seconds depending on the location and size of the guide star. Once I couldn t find a guide star then rotated the camera then
            Message 5 of 8 , Jun 19, 2000
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              I was using 3-4 seconds then 5-7 seconds depending on the location and size of the guide star.  Once I couldn't find a guide star then rotated the camera then found a guide star but took 7 second exposures with a 10 second calibration.  I thought the move was too big compared to the exposure.  Ya know kinda like if yu are exposing you ain't correctin.....
               
              thanks Ron
              Brian
              ----- Original Message -----
              Sent: Monday, June 19, 2000 4:44 PM
              Subject: RE: [ccd-newastro]

              One other idea -- how long was your guide exposure? Sometimes, you can eliminate this kind of oscillation simply by going to a longer guide exposure. I typically use guide exposures of around 4-5 seconds.
               
              Ron Wodaski
              -----Original Message-----
              From: Focus [mailto:focus@...]
              Sent: Monday, June 19, 2000 10:26 AM
              To: ccd-newastro@egroups.com
              Subject: [ccd-newastro]

              Hey guys,
              I took this last night with an ap 1200 mount.  I took an ok 60 second guided shot and then tried guiding, focal length 1600mm.  I used .5 guiding and calibrated at .5x.  When I did the star stayed on the little autoguiding chip the whole exposure.  I did not play with backlash at all.  I used a bunch of different settings on maxim guiding, but didn't try to change backlash in guider settings. 
              I even tried the Roland calibrate at 1x and guide at .5x trick and got the same results. 
              I think it is dec backlash, can anyone help?  The ap mount manual says to depress one dip switch at a time till backlash gone.  I was too tuckered out to mess with it. 
              thanks
              Brian


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            • Ron Wodaski
              Hey, if you need some company, just send a plane for me. I m always in favor of heading for dark skies. The Maxim backlash settings will be IN ADDITION
              Message 6 of 8 , Jun 21, 2000
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                Hey, if you need some company, just send a plane for me. <g> I'm always in favor of heading for dark skies. <g>
                 
                The Maxim backlash settings will be IN ADDITION to your hand controller backlash settings. I haven't yet written up the procedure for getting your mount optimized for guiding, but it's very near to the top of the list of things to write about. Once you get the mount physically optimized, you can refine it via the software. The overall procedure:
                 
                * Physically adjust the mount to remove inappropriate free play in RA and Dec. How you do this varies with the mount.
                 
                * Visually adjust your backlash settings, so that RA moves without jerkiness or pauses at 12X (or a similar speed), and so that DEC moves without jerks or pauses at 1X. How you do this...you get the idea. <g>
                 
                * Confirm your backlash settings using your camera control software. Usually, this means imaging and changing directions at guiding speeds for fixed intervals, and measuring the results. For example:
                 
                  - take a reference image
                  - move the mount +RA for ten seconds at .5x
                  - measure movement, then move the mount -RA for ten seconds at .5X
                  - Movement should be the same; if not, increase backlash and repeat. If worse, reduce backlash on hand controller. If better, keep going until you have optimal results (as close to equal movement as possible). Maxim's Move button in the guide dialog can help with this, or you can just do a calibrate and observe the movements.
                  - repeat for Dec.
                 
                * Make some test exposures to determine the correct aggressiveness setting to use with your mount. The better aligned you are to the pole, the less aggressiveness is needed. If your mount has small periodic error, you can reduce aggressiveness even further. Basically, you want to make a correction only when one is necessary. Guiding always has the potential to mess up the image, so the ideal exposure wouldn't require guiding at all. <g> Good polar alignment, low periodic error, and gentle aggressiveness setting all contribute to the desired goal: the fewest and smallest corrections possible during each exposure. In my experience, the default settings are far too aggressive when you have a decent polar alignment.
                 
                Get the 1100, from what I've heard via Herb York at Anacortes. The only caution: it's NOT portable. Um, I'll take your used 1200. <g>
                 
                I really like the NJP. Only mount I've ever owned that never makes me nervous about guiding. Every other mount I've owned, I've had to baby-sit it to see if it was going to guide OK. With the NJP, I just expose/calibrate/track. Works every time.
                -----Original Message-----
                From: Focus [mailto:focus@...]
                Sent: Monday, June 19, 2000 7:16 PM
                To: ccd-newastro@egroups.com
                Subject: Re: [ccd-newastro]

                Hi Ron,
                 
                Thanks for the invaluable tips.  I was so frustrated man o man.  Wanna come out here for a night or two?  I got lots of mounts and scopes and cameras......
                 
                Are the Maxim backlash settings the same thing as using the backlash settings on the mount?  I haven't reset those. 
                 
                I have the 400 goto moutn set as you did in AZ, should I do this also for the 1200 or just buy a Paramount 1100?  <g>
                 
                I trust you still like the njp, I got hold of one and will be using it as my dark site mount.  Are you just going through gear for the book or really trying to find good stuff?  What happened with the gpdx? I printed your web page and am reading it tonight about that mount.  I think my 400 is in the launch position....
                 
                take care and let's start this group rolling, huh?
                Brian
                ----- Original Message -----
                Sent: Monday, June 19, 2000 4:39 PM
                Subject: RE: [ccd-newastro]

                If you are using Maxim, you can check your backlash settings using the software. Position yourself at a star near the celestial equator, so that movement in Dec and RA will be similar.
                 
                When the Guide tab is active, note that there is a button labeled Move. Click this button to open a Move dialog. Make sure the mount is set to move at your guide rate (typically .5x). You have a fairly long focal length, 1600mm, so I would suggest that you try a move duration of 5 seconds.
                 
                Click the +X button to get things started. Ignore the amount of movement. Note the position of a bright star. .
                 
                Now click -X, note the position, and then click +X again. Does the star return to the same position as it was in before? In other words, are the movements the same amount?
                 
                Now do the same process for Y. Is the magnitude of the movement the same, larger, smaller? The two directions should move close to the same amount. If not, it's likely that you have a problem with backlash settings. A little experimentation should confirm whether you have too little, or too much backlash. The Guide Settings dialog allows you to use software backlash adjustments, and you can observe the results of these changes in order to determine how your backlash settings are.
                 
                You can also check your backlash visually; the AP manual has good instructions for doing this. Be patient with the process; it takes a bit of time to get a feel for what is best. You definitely are better off having too little backlash compensation, because you can do additional compensation in the software settings. If you have too much, it will cause results like you already have seen. <g>
                 
                Other factors that might contribute to the duplicate star images:
                 
                * A too-perfectly balanced mount. You want a little excess weight on the east side of the mount, to keep the gears always meshed and pushing "up hill."
                 
                * Too high of an aggressiveness setting. This can push the mount harder than it needs to be pushed, or cause the mount to overreact to twinkling of stars.
                 
                * To long of a maximum duration of movement; try cutting this down.
                 
                But backlash is the usually culprit; it sounds like you have too much.
                 
                Ron Wodaski
                -----Original Message-----
                From: Focus [mailto:focus@...]
                Sent: Monday, June 19, 2000 10:26 AM
                To: ccd-newastro@egroups.com
                Subject: [ccd-newastro]

                Hey guys,
                I took this last night with an ap 1200 mount.  I took an ok 60 second guided shot and then tried guiding, focal length 1600mm.  I used .5 guiding and calibrated at .5x.  When I did the star stayed on the little autoguiding chip the whole exposure.  I did not play with backlash at all.  I used a bunch of different settings on maxim guiding, but didn't try to change backlash in guider settings. 
                I even tried the Roland calibrate at 1x and guide at .5x trick and got the same results. 
                I think it is dec backlash, can anyone help?  The ap mount manual says to depress one dip switch at a time till backlash gone.  I was too tuckered out to mess with it. 
                thanks
                Brian



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                ccd-newastro-unsubscribe@egroups.com




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              • Ron Wodaski
                Generally, I try to polar align well enough that I could take a one-minute exposure without star trails. Thus, a ten-second guide interval is actually fine --
                Message 7 of 8 , Jun 21, 2000
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                  Generally, I try to polar align well enough that I could take a one-minute exposure without star trails. Thus, a ten-second guide interval is actually fine -- it's one sixth of that. With good quality mounts -- yours should qualify -- a good polar alignment can make the guiding experience painless, as explained in some detail in my previous message.
                   
                  Ron Wodaski
                  -----Original Message-----
                  From: Focus [mailto:focus@...]
                  Sent: Monday, June 19, 2000 7:24 PM
                  To: ccd-newastro@egroups.com
                  Subject: Re: [ccd-newastro]

                  I was using 3-4 seconds then 5-7 seconds depending on the location and size of the guide star.  Once I couldn't find a guide star then rotated the camera then found a guide star but took 7 second exposures with a 10 second calibration.  I thought the move was too big compared to the exposure.  Ya know kinda like if yu are exposing you ain't correctin.....
                   
                  thanks Ron
                  Brian
                  ----- Original Message -----
                  Sent: Monday, June 19, 2000 4:44 PM
                  Subject: RE: [ccd-newastro]

                  One other idea -- how long was your guide exposure? Sometimes, you can eliminate this kind of oscillation simply by going to a longer guide exposure. I typically use guide exposures of around 4-5 seconds.
                   
                  Ron Wodaski
                  -----Original Message-----
                  From: Focus [mailto:focus@...]
                  Sent: Monday, June 19, 2000 10:26 AM
                  To: ccd-newastro@egroups.com
                  Subject: [ccd-newastro]

                  Hey guys,
                  I took this last night with an ap 1200 mount.  I took an ok 60 second guided shot and then tried guiding, focal length 1600mm.  I used .5 guiding and calibrated at .5x.  When I did the star stayed on the little autoguiding chip the whole exposure.  I did not play with backlash at all.  I used a bunch of different settings on maxim guiding, but didn't try to change backlash in guider settings. 
                  I even tried the Roland calibrate at 1x and guide at .5x trick and got the same results. 
                  I think it is dec backlash, can anyone help?  The ap mount manual says to depress one dip switch at a time till backlash gone.  I was too tuckered out to mess with it. 
                  thanks
                  Brian


                  To unsubscribe from this group, send an email to:
                  ccd-newastro-unsubscribe@egroups.com




                  To unsubscribe from this group, send an email to:
                  ccd-newastro-unsubscribe@egroups.com




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                • Focus
                  thanks Ron again..... brian ... From: Ron Wodaski To: ccd-newastro@egroups.com Sent: Wednesday, June 21, 2000 5:31 PM Subject: RE: [ccd-newastro] Generally, I
                  Message 8 of 8 , Jun 21, 2000
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                    thanks Ron again.....
                    brian
                    ----- Original Message -----
                    Sent: Wednesday, June 21, 2000 5:31 PM
                    Subject: RE: [ccd-newastro]

                    Generally, I try to polar align well enough that I could take a one-minute exposure without star trails. Thus, a ten-second guide interval is actually fine -- it's one sixth of that. With good quality mounts -- yours should qualify -- a good polar alignment can make the guiding experience painless, as explained in some detail in my previous message.
                     
                    Ron Wodaski
                    -----Original Message-----
                    From: Focus [mailto:focus@...]
                    Sent: Monday, June 19, 2000 7:24 PM
                    To: ccd-newastro@egroups.com
                    Subject: Re: [ccd-newastro]

                    I was using 3-4 seconds then 5-7 seconds depending on the location and size of the guide star.  Once I couldn't find a guide star then rotated the camera then found a guide star but took 7 second exposures with a 10 second calibration.  I thought the move was too big compared to the exposure.  Ya know kinda like if yu are exposing you ain't correctin.....
                     
                    thanks Ron
                    Brian
                    ----- Original Message -----
                    Sent: Monday, June 19, 2000 4:44 PM
                    Subject: RE: [ccd-newastro]

                    One other idea -- how long was your guide exposure? Sometimes, you can eliminate this kind of oscillation simply by going to a longer guide exposure. I typically use guide exposures of around 4-5 seconds.
                     
                    Ron Wodaski
                    -----Original Message-----
                    From: Focus [mailto:focus@...]
                    Sent: Monday, June 19, 2000 10:26 AM
                    To: ccd-newastro@egroups.com
                    Subject: [ccd-newastro]

                    Hey guys,
                    I took this last night with an ap 1200 mount.  I took an ok 60 second guided shot and then tried guiding, focal length 1600mm.  I used .5 guiding and calibrated at .5x.  When I did the star stayed on the little autoguiding chip the whole exposure.  I did not play with backlash at all.  I used a bunch of different settings on maxim guiding, but didn't try to change backlash in guider settings. 
                    I even tried the Roland calibrate at 1x and guide at .5x trick and got the same results. 
                    I think it is dec backlash, can anyone help?  The ap mount manual says to depress one dip switch at a time till backlash gone.  I was too tuckered out to mess with it. 
                    thanks
                    Brian


                    To unsubscribe from this group, send an email to:
                    ccd-newastro-unsubscribe@egroups.com




                    To unsubscribe from this group, send an email to:
                    ccd-newastro-unsubscribe@egroups.com




                    To unsubscribe from this group, send an email to:
                    ccd-newastro-unsubscribe@egroups.com




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