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Re: UI Lockup during Image download

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  • dc3dreamer
    CHris is on the right track. Many CCD cameras are unbuffered. They read right off the sensor and into main memory of the computer. In order to prevent banding
    Message 1 of 26 , Feb 19, 2012
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      CHris is on the right track. Many CCD cameras are unbuffered. They read right off the sensor and into main memory of the computer. In order to prevent banding caused by reading off the chip at an unever rate, most of these cameras' drivers grab hold of the CPU and effectively lock out the rest of the system. This is a hangover from the old DOS days that unfortunately has only recently seen improvement by adding image buffers to the cameras. I'm guessing you have an SBIG camera?

      -- Bob

      --- In ASCOM-Talk@yahoogroups.com, "Chris" <chris_group_mail@...> wrote:
      >
      > This may be a something that the low level camera driver is doing. Have you tried other drivers, such as the simulators?
      >
      > Chris
      >
      > --- In ASCOM-Talk@yahoogroups.com, "Ken" <kenpendlebury@> wrote:
      > >
      > > Thanks for the thoughts and reply Paul. Unfortunately, I experimented with priorities (after your suggestion) by putting the download thread at the lowest priority while the main (UI) thread remained at normal. This did not yield different results.
      > >
      > > In terms of the threads becoming synchronized, I don't think this is happening. The only method called in this thread is to capture and download an image. The method is not actually aware of other threads like the UI so there is no contention for resources that would cause one thread to wait on another.
      > >
      > > I will keep looking...
      > >
      > > Thanks again,
      > > Ken
      > >
      > > --- In ASCOM-Talk@yahoogroups.com, "paulkccd" <yh@> wrote:
      > > >
      > > > Two likely possibilities:
      > > >
      > > > 1. The download thread executes at a raised priority, not letting other threads execute until it's done.
      > > >
      > > > 2. The UI thread becomes synchronized with the download thread due to UI update calls or some other cross-thread operation(s).
      > > >
      > > > Regards,
      > > >
      > > > -Paul
      > > >
      > > >
      > > > --- In ASCOM-Talk@yahoogroups.com, "Ken" <kenpendlebury@> wrote:
      > > > >
      > > > > Hi folks,
      > > > >
      > > > > We are building an application that requires the UI to be responsive during rapid image download (like for a frame and focus routine). I just want to see if anyone else has encountered similar problems and found a way around them.
      > > > >
      > > > > In any normal application, you can simply place "work" like this into a background thread and the UI will continue to remain responsive. We have a setup quite similar to this... the UI runs in the main process thread and the capture and subsequent download of data occurs in a background thread. Despite the separation of work, the UI continues to lockup when the ASCOM camera transfers data to the host computer. It looks to us like the entire process (all threads) become unresponsive when this happens.
      > > > >
      > > > > There appears to be something we don't know about threading and accessing hardware like USB ports...
      > > > >
      > > > > Has anyone experienced anything like this?
      > > > >
      > > > > We are using ASCOM 6, C# and .NET 4
      > > > >
      > > > > Thanks for any help,
      > > > > Ken
      > > > >
      > > >
      > >
      >
    • Howard Anderson
      Hi, Have been doing calibration and testing of components of my new observatory at Rancho Hidalgo, NM. I am using a TCF-Si focuser. In order for it to
      Message 2 of 26 , Feb 19, 2012
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        Hi,

        Have been doing calibration and testing of components of my new
        observatory at Rancho Hidalgo, NM.

        I am using a TCF-Si focuser.  In order for it to maintain focus as
        the temperature changes, it either has to be connected in Maxim DL
        or connected to Optec's "TCF-S Focuser Control".   Each of
        these programs monitors the temperature and issues commands to
        the focuser to run the stepper motor and maintain focus.

        If I try to use "Enable Autofocus" in ACP Preferences
        then FocusMax is apparently chosen as the focus control system.  It looks
        like I cannot substitute MaximDL or the Optec software for this
        function?

        Question is this:
        Does FocusMax handle the temperature monitoring and control
        of the TCF-Si focuser?
        It looks like FocusMax is designed to refocus when so instructed but not
        designed to accommodate a temperature controlled focuser.

        I would like to use "Enable Autofocus" in ACP and the "#AUTOFOCUS"
        command once and only once at the beginning of the night's "AcquireImages.js"
        plan run then have the TCF-Si focuser adapt the focus to temperature changes
        automatically.

        It looks like FocusMax is the only ACP focusing interface and that it will
        not monitor the TCF-Si temperature and automatically maintain focus
        by issuing Optec commands to the focuser as the temperature changes?

        Did I miss something?

        (A possible alternative would be for me to modify the beginning of
        AcquireImages.js to do a Maxim DL autofocus operation at the
        beginning of a run if indeed FocusMax will not maintain TCF-Si focusing.)

        Just trying to get this all automated and reduce the chance of me starting
        up a run and forgetting to set the initial focus...

        Thanks,

        Howard
        Support@...


      • THouse
        Howard, I would ask Steve Brady (Author of FM) on the Yahoo FM Group (FMaxUG). There is a beta version that does temp comp but not sure how main stream it is
        Message 3 of 26 , Feb 19, 2012
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          Howard,
          I would ask Steve Brady (Author of FM) on the Yahoo FM Group (FMaxUG).
          There is a beta version that does temp comp but not sure how main stream it is right now.

          Tom

          On 2/19/2012 8:01 PM, Howard Anderson wrote:
           

          Hi,

          Have been doing calibration and testing of components of my new
          observatory at Rancho Hidalgo, NM.

          I am using a TCF-Si focuser.  In order for it to maintain focus as
          the temperature changes, it either has to be connected in Maxim DL
          or connected to Optec's "TCF-S Focuser Control".   Each of
          these programs monitors the temperature and issues commands to
          the focuser to run the stepper motor and maintain focus.

          If I try to use "Enable Autofocus" in ACP Preferences
          then FocusMax is apparently chosen as the focus control system.  It looks
          like I cannot substitute MaximDL or the Optec software for this
          function?

          Question is this:

          Does FocusMax handle the temperature monitoring and control
          of the TCF-Si focuser?
          It looks like FocusMax is designed to refocus when so instructed but not
          designed to accommodate a temperature controlled focuser.

          I would like to use "Enable Autofocus" in ACP and the "#AUTOFOCUS"
          command once and only once at the beginning of the night's "AcquireImages.js"
          plan run then have the TCF-Si focuser adapt the focus to temperature changes
          automatically.

          It looks like FocusMax is the only ACP focusing interface and that it will
          not monitor the TCF-Si temperature and automatically maintain focus
          by issuing Optec commands to the focuser as the temperature changes?

          Did I miss something?

          (A possible alternative would be for me to modify the beginning of
          AcquireImages.js to do a Maxim DL autofocus operation at the
          beginning of a run if indeed FocusMax will not maintain TCF-Si focusing.)

          Just trying to get this all automated and reduce the chance of me starting
          up a run and forgetting to set the initial focus...

          Thanks,

          Howard
          Support@...


        • Jim Jones
          Hi Howard I ve been trying to do exactly what you are attempting with some but only some success. Last summer I was focusing with MaxIm at the beginning of the
          Message 4 of 26 , Feb 19, 2012
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            Hi Howard

            I've been trying to do exactly what you are attempting with some but
            only some success.

            Last summer I was focusing with MaxIm at the beginning of the evening
            and then letting MaxIm control the focuser for temp. I was cutting ACP
            completely out of the loop. This was fine for temp changes and I could
            go a whole night without focusing. But then again I was imaging for
            photometry and focus doesn't have to be absolutely perfect.

            The problem was that I could not change filters (using filter offsets)
            since MaxIm didn't know what filter ACP was using.

            I am just returning to this issue and for this observing season, I plan
            on trying a two prong approach.

            First I'm going to try to get the FocusMax beta that incorporates temp
            coeffficients from Steve Brady. Then I would enable autofocus in ACP.
            Tom Kraji is succesfully using the beta now.

            Second, I am also going to attempt to connect both FocusMax and Maxim to
            the focuser through POTH. Then I can enable autofocus in ACP. ACP
            should be able to provide corrections for filter offsets and MaxIm for
            temp changes. I'm not at all sure this will work. Hopefully I will get
            a chance to try this out next week.

            In many ways it would be nice to get FocusMax completely out of the
            picture. It is a very complex program and I have had it abort an nights
            imaging on more than one occasion.

            Somebody made a suggestion to Bob Denny that ACP also provide the
            capability to connect to the focuser driver through MaxIm. I spoke
            supporting the proposal but to say it got a chilly reception would be an
            understatement.

            For Jeff....one very nice solution would be for the OpTec Driver to act
            as a hub.

            Jim Jones






            Howard Anderson wrote:
            > Hi,
            >
            > Have been doing calibration and testing of components of my new
            > observatory at Rancho Hidalgo, NM.
            >
            > I am using a TCF-Si focuser. In order for it to maintain focus as
            > the temperature changes, it either has to be connected in Maxim DL
            > or connected to Optec's "TCF-S Focuser Control". Each of
            > these programs monitors the temperature and issues commands to
            > the focuser to run the stepper motor and maintain focus.
            >
            > If I try to use "Enable Autofocus" in ACP Preferences
            > then FocusMax is apparently chosen as the focus control system. It looks
            > like I cannot substitute MaximDL or the Optec software for this
            > function?
            >
            > Question is this:
            >
            > Does FocusMax handle the temperature monitoring and control
            > of the TCF-Si focuser?
            >
            > It looks like FocusMax is designed to refocus when so instructed but not
            > designed to accommodate a temperature controlled focuser.
            >
            > I would like to use "Enable Autofocus" in ACP and the "#AUTOFOCUS"
            > command once and only once at the beginning of the night's
            > "AcquireImages.js"
            > plan run then have the TCF-Si focuser adapt the focus to temperature
            > changes
            > automatically.
            >
            > It looks like FocusMax is the only ACP focusing interface and that it
            > will
            > not monitor the TCF-Si temperature and automatically maintain focus
            > by issuing Optec commands to the focuser as the temperature changes?
            >
            > Did I miss something?
            >
            > (A possible alternative would be for me to modify the beginning of
            > AcquireImages.js to do a Maxim DL autofocus operation at the
            > beginning of a run if indeed FocusMax will not maintain TCF-Si focusing.)
            >
            > Just trying to get this all automated and reduce the chance of me
            > starting
            > up a run and forgetting to set the initial focus...
            >
            > Thanks,
            >
            > Howard
            > Support@...
            >
            >
            >
          • Howard Anderson
            Hi Tom and Jim, Thanks for the info on Steve Brady Tom. Jim... When I use ACP, it uses Maxim DL for all imaging including filter selection. Tests I did a few
            Message 5 of 26 , Feb 20, 2012
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              Hi Tom and Jim,

              Thanks for the info on Steve Brady Tom.

              Jim...

              When I use ACP, it uses Maxim DL for all imaging including
              filter selection.  Tests I did a few weeks ago showed that when
              a new filter was selected, the filter offsets that I stored in Maxim DL
              were automatically applied when the filter was selected.  I checked
              the TCF-Si "position" counter and it moved according to the offset
              of the selected filter. 

              Looks like you were using ACP instead of  Maxim DL to
              store the filter offsets?  The Maxim DL filter offsets can be set up
              from the Camera Control window.  You have to select "Setup Filter"
              but you have to do it when the camera is not connected.  I had
              a heck of a time finding this even though it looks simple now.  Searches
              of the Maxim DL help file did not easily lead to the Camera Control
              Window's "Setup Filter" button.  You sort of already have to know
              it is on the Camera Control panel.  :-)

              I have Astrodon LRGB filters and all testing has shown that they are
              essentially parfocal as advertised.  I do have one H-Alpha filter
              that I recently inserted that will NOT be parfocal so I will take
              data on that, determine the offset, and install the offset into
              Maxim DL.  Just as soon as I get an uncloudy
              night at Rancho Hidalgo - Looks like Tuesday maybe...

              I am not asking for anyone to do any new work on ACP or the focuser
              interfaces.  I am  just trying to make sure that I understand how the
              current system works so I don't reinvent any wheels.

              Thanks again guys,

              Howard


              Jim Jones wrote:
               

              Hi Howard

              I've been trying to do exactly what you are attempting with some but
              only some success.

              Last summer I was focusing with MaxIm at the beginning of the evening
              and then letting MaxIm control the focuser for temp. I was cutting ACP
              completely out of the loop. This was fine for temp changes and I could
              go a whole night without focusing. But then again I was imaging for
              photometry and focus doesn't have to be absolutely perfect.

              The problem was that I could not change filters (using filter offsets)
              since MaxIm didn't know what filter ACP was using.

              I am just returning to this issue and for this observing season, I plan
              on trying a two prong approach.

              First I'm going to try to get the FocusMax beta that incorporates temp
              coeffficients from Steve Brady. Then I would enable autofocus in ACP.
              Tom Kraji is succesfully using the beta now.

              Second, I am also going to attempt to connect both FocusMax and Maxim to
              the focuser through POTH. Then I can enable autofocus in ACP. ACP
              should be able to provide corrections for filter offsets and MaxIm for
              temp changes. I'm not at all sure this will work. Hopefully I will get
              a chance to try this out next week.

              In many ways it would be nice to get FocusMax completely out of the
              picture. It is a very complex program and I have had it abort an nights
              imaging on more than one occasion.

              Somebody made a suggestion to Bob Denny that ACP also provide the
              capability to connect to the focuser driver through MaxIm. I spoke
              supporting the proposal but to say it got a chilly reception would be an
              understatement.

              For Jeff....one very nice solution would be for the OpTec Driver to act
              as a hub.

              Jim Jones

              Howard Anderson wrote:
              > Hi,
              >
              > Have been doing calibration and testing of components of my new
              > observatory at Rancho Hidalgo, NM.
              >
              > I am using a TCF-Si focuser. In order for it to maintain focus as
              > the temperature changes, it either has to be connected in Maxim DL
              > or connected to Optec's "TCF-S Focuser Control". Each of
              > these programs monitors the temperature and issues commands to
              > the focuser to run the stepper motor and maintain focus.
              >
              > If I try to use "Enable Autofocus" in ACP Preferences
              > then FocusMax is apparently chosen as the focus control system. It looks
              > like I cannot substitute MaximDL or the Optec software for this
              > function?
              >
              > Question is this:
              >
              > Does FocusMax handle the temperature monitoring and control
              > of the TCF-Si focuser?
              >
              > It looks like FocusMax is designed to refocus when so instructed but not
              > designed to accommodate a temperature controlled focuser.
              >
              > I would like to use "Enable Autofocus" in ACP and the "#AUTOFOCUS"
              > command once and only once at the beginning of the night's
              > "AcquireImages.js"
              > plan run then have the TCF-Si focuser adapt the focus to temperature
              > changes
              > automatically.
              >
              > It looks like FocusMax is the only ACP focusing interface and that it
              > will
              > not monitor the TCF-Si temperature and automatically maintain focus
              > by issuing Optec commands to the focuser as the temperature changes?
              >
              > Did I miss something?
              >
              > (A possible alternative would be for me to modify the beginning of
              > AcquireImages.js to do a Maxim DL autofocus operation at the
              > beginning of a run if indeed FocusMax will not maintain TCF-Si focusing.)
              >
              > Just trying to get this all automated and reduce the chance of me
              > starting
              > up a run and forgetting to set the initial focus...
              >
              > Thanks,
              >
              > Howard
              > Support@...
              >
              >
              >


            • Ken
              Thanks for the feedback. We are getting reports of this behavior right now mostly for ASCOM cameras (Atik 8300 in particular). I am not sure if this behavior
              Message 6 of 26 , Feb 20, 2012
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                Thanks for the feedback. We are getting reports of this behavior right now mostly for ASCOM cameras (Atik 8300 in particular). I am not sure if this behavior is present with the SBIG camera.

                --- In ASCOM-Talk@yahoogroups.com, "dc3dreamer" <rdenny@...> wrote:
                >
                > CHris is on the right track. Many CCD cameras are unbuffered. They read right off the sensor and into main memory of the computer. In order to prevent banding caused by reading off the chip at an unever rate, most of these cameras' drivers grab hold of the CPU and effectively lock out the rest of the system. This is a hangover from the old DOS days that unfortunately has only recently seen improvement by adding image buffers to the cameras. I'm guessing you have an SBIG camera?
                >
                > -- Bob
                >
                > --- In ASCOM-Talk@yahoogroups.com, "Chris" <chris_group_mail@> wrote:
                > >
                > > This may be a something that the low level camera driver is doing. Have you tried other drivers, such as the simulators?
                > >
                > > Chris
                > >
                > > --- In ASCOM-Talk@yahoogroups.com, "Ken" <kenpendlebury@> wrote:
                > > >
                > > > Thanks for the thoughts and reply Paul. Unfortunately, I experimented with priorities (after your suggestion) by putting the download thread at the lowest priority while the main (UI) thread remained at normal. This did not yield different results.
                > > >
                > > > In terms of the threads becoming synchronized, I don't think this is happening. The only method called in this thread is to capture and download an image. The method is not actually aware of other threads like the UI so there is no contention for resources that would cause one thread to wait on another.
                > > >
                > > > I will keep looking...
                > > >
                > > > Thanks again,
                > > > Ken
                > > >
                > > > --- In ASCOM-Talk@yahoogroups.com, "paulkccd" <yh@> wrote:
                > > > >
                > > > > Two likely possibilities:
                > > > >
                > > > > 1. The download thread executes at a raised priority, not letting other threads execute until it's done.
                > > > >
                > > > > 2. The UI thread becomes synchronized with the download thread due to UI update calls or some other cross-thread operation(s).
                > > > >
                > > > > Regards,
                > > > >
                > > > > -Paul
                > > > >
                > > > >
                > > > > --- In ASCOM-Talk@yahoogroups.com, "Ken" <kenpendlebury@> wrote:
                > > > > >
                > > > > > Hi folks,
                > > > > >
                > > > > > We are building an application that requires the UI to be responsive during rapid image download (like for a frame and focus routine). I just want to see if anyone else has encountered similar problems and found a way around them.
                > > > > >
                > > > > > In any normal application, you can simply place "work" like this into a background thread and the UI will continue to remain responsive. We have a setup quite similar to this... the UI runs in the main process thread and the capture and subsequent download of data occurs in a background thread. Despite the separation of work, the UI continues to lockup when the ASCOM camera transfers data to the host computer. It looks to us like the entire process (all threads) become unresponsive when this happens.
                > > > > >
                > > > > > There appears to be something we don't know about threading and accessing hardware like USB ports...
                > > > > >
                > > > > > Has anyone experienced anything like this?
                > > > > >
                > > > > > We are using ASCOM 6, C# and .NET 4
                > > > > >
                > > > > > Thanks for any help,
                > > > > > Ken
                > > > > >
                > > > >
                > > >
                > >
                >
              • Jim Jones
                Howard My experiences with the Astrodon v and c filters have been somewhat different than yours. The change is very significant. My br and i are from a
                Message 7 of 26 , Feb 20, 2012
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                  Howard

                  My experiences with the Astrodon v and c filters have been somewhat
                  different than yours. The change is very significant. My br and i are
                  from a different mfg so I would expect to have to refocus.

                  No my filter offsets are stored in MaxIm. I am going to run some
                  simulations this week and I'll double check how MaxIm works. Basically
                  you need two things to happen; 1) recognize that ACP has in fact
                  changed filters. and (2) ACP recognize that MaxIm is changing focus and
                  not start a new image until the focuser has stopped. For other reasons.
                  I don't want to have to crank in a delay between every image to handle
                  this issue.

                  I would be interested to hear how your H-Alpha tests come out.

                  Jim Jones

                  Howard Anderson wrote:
                  > Hi Tom and Jim,
                  >
                  > Thanks for the info on Steve Brady Tom.
                  >
                  > Jim...
                  >
                  > When I use ACP, it uses Maxim DL for all imaging including
                  > filter selection. Tests I did a few weeks ago showed that when
                  > a new filter was selected, the filter offsets that I stored in Maxim DL
                  > were automatically applied when the filter was selected. I checked
                  > the TCF-Si "position" counter and it moved according to the offset
                  > of the selected filter.
                  > Looks like you were using ACP instead of Maxim DL
                  > store the filter offsets? The Maxim DL filter offsets can be set up
                  > from the Camera Control window. You have to select "Setup Filter"
                  > but you have to do it when the camera is not connected. I had
                  > a heck of a time finding this even though it looks simple now. Searches
                  > of the Maxim DL help file did not easily lead to the Camera Control
                  > Window's "Setup Filter" button. You sort of already have to know
                  > it is on the Camera Control panel. :-)
                  >
                  > I have Astrodon LRGB filters and all testing has shown that they are
                  > essentially parfocal as advertised. I do have one H-Alpha filter
                  > that I recently inserted that will NOT be parfocal so I will take
                  > data on that, determine the offset, and install the offset into
                  > Maxim DL. Just as soon as I get an uncloudy
                  > night at Rancho Hidalgo - Looks like Tuesday maybe...
                  >
                  > I am not asking for anyone to do any new work on ACP or the focuser
                  > interfaces. I am just trying to make sure that I understand how the
                  > current system works so I don't reinvent any wheels.
                  >
                  > Thanks again guys,
                  >
                  > Howard
                  >
                  >
                  > Jim Jones wrote:
                  >
                  >>
                  >>
                  >> Hi Howard
                  >>
                  >> I've been trying to do exactly what you are attempting with some but
                  >> only some success.
                  >>
                  >> Last summer I was focusing with MaxIm at the beginning of the evening
                  >> and then letting MaxIm control the focuser for temp. I was cutting ACP
                  >> completely out of the loop. This was fine for temp changes and I could
                  >> go a whole night without focusing. But then again I was imaging for
                  >> photometry and focus doesn't have to be absolutely perfect.
                  >>
                  >> The problem was that I could not change filters (using filter offsets)
                  >> since MaxIm didn't know what filter ACP was using.
                  >>
                  >> I am just returning to this issue and for this observing season, I plan
                  >> on trying a two prong approach.
                  >>
                  >> First I'm going to try to get the FocusMax beta that incorporates temp
                  >> coeffficients from Steve Brady. Then I would enable autofocus in ACP.
                  >> Tom Kraji is succesfully using the beta now.
                  >>
                  >> Second, I am also going to attempt to connect both FocusMax and Maxim to
                  >> the focuser through POTH. Then I can enable autofocus in ACP. ACP
                  >> should be able to provide corrections for filter offsets and MaxIm for
                  >> temp changes. I'm not at all sure this will work. Hopefully I will get
                  >> a chance to try this out next week.
                  >>
                  >> In many ways it would be nice to get FocusMax completely out of the
                  >> picture. It is a very complex program and I have had it abort an nights
                  >> imaging on more than one occasion.
                  >>
                  >> Somebody made a suggestion to Bob Denny that ACP also provide the
                  >> capability to connect to the focuser driver through MaxIm. I spoke
                  >> supporting the proposal but to say it got a chilly reception would be an
                  >> understatement.
                  >>
                  >> For Jeff....one very nice solution would be for the OpTec Driver to act
                  >> as a hub.
                  >>
                  >> Jim Jones
                  >>
                  >> Howard Anderson wrote:
                  >> > Hi,
                  >> >
                  >> > Have been doing calibration and testing of components of my new
                  >> > observatory at Rancho Hidalgo, NM.
                  >> >
                  >> > I am using a TCF-Si focuser. In order for it to maintain focus as
                  >> > the temperature changes, it either has to be connected in Maxim DL
                  >> > or connected to Optec's "TCF-S Focuser Control". Each of
                  >> > these programs monitors the temperature and issues commands to
                  >> > the focuser to run the stepper motor and maintain focus.
                  >> >
                  >> > If I try to use "Enable Autofocus" in ACP Preferences
                  >> > then FocusMax is apparently chosen as the focus control system. It
                  >> looks
                  >> > like I cannot substitute MaximDL or the Optec software for this
                  >> > function?
                  >> >
                  >> > Question is this:
                  >> >
                  >> > Does FocusMax handle the temperature monitoring and control
                  >> > of the TCF-Si focuser?
                  >> >
                  >> > It looks like FocusMax is designed to refocus when so instructed
                  >> but not
                  >> > designed to accommodate a temperature controlled focuser.
                  >> >
                  >> > I would like to use "Enable Autofocus" in ACP and the "#AUTOFOCUS"
                  >> > command once and only once at the beginning of the night's
                  >> > "AcquireImages.js"
                  >> > plan run then have the TCF-Si focuser adapt the focus to temperature
                  >> > changes
                  >> > automatically.
                  >> >
                  >> > It looks like FocusMax is the only ACP focusing interface and that it
                  >> > will
                  >> > not monitor the TCF-Si temperature and automatically maintain focus
                  >> > by issuing Optec commands to the focuser as the temperature changes?
                  >> >
                  >> > Did I miss something?
                  >> >
                  >> > (A possible alternative would be for me to modify the beginning of
                  >> > AcquireImages.js to do a Maxim DL autofocus operation at the
                  >> > beginning of a run if indeed FocusMax will not maintain TCF-Si
                  >> focusing.)
                  >> >
                  >> > Just trying to get this all automated and reduce the chance of me
                  >> > starting
                  >> > up a run and forgetting to set the initial focus...
                  >> >
                  >> > Thanks,
                  >> >
                  >> > Howard
                  >> > Support@... <mailto:Support%40AZcendant.com>
                  >> >
                  >> >
                  >> >
                  >>
                  >>
                  >
                  >
                  >
                • Tim Long
                  As others have mentioned, the likelihood is that the kernel mode driver is in fact causing the entire process to block. There s nothing inherent to ASCOM that
                  Message 8 of 26 , Feb 20, 2012
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                    As others have mentioned, the likelihood is that the kernel mode driver
                    is in fact causing the entire process to block. There's nothing inherent
                    to ASCOM that controls this behaviour, although it is possible that your
                    specific driver implementation is doing something a bit unfriendly. I
                    think Chris mentioned that you could use the simulator as a reference
                    implementation, but of course that can't model all the timing
                    characteristics of actual hardware.

                    It sounds like you might be reasonably experienced so I'm sure you
                    understand that multi-threading is non-trivial and has many pitfalls.
                    How does your background thread communicate with the GUI thread? Is it
                    possible that you have a race condition or a deadlock? Are you making
                    cross-thread GUI updates?

                    --Tim Long

                    -----Original Message-----
                    From: ASCOM-Talk@yahoogroups.com [mailto:ASCOM-Talk@yahoogroups.com] On
                    Behalf Of Ken
                    Sent: 18 February 2012 22:03
                    To: ASCOM-Talk@yahoogroups.com
                    Subject: [ASCOM] UI Lockup during Image download

                    Hi folks,

                    We are building an application that requires the UI to be responsive
                    during rapid image download (like for a frame and focus routine). I
                    just want to see if anyone else has encountered similar problems and
                    found a way around them.

                    In any normal application, you can simply place "work" like this into a
                    background thread and the UI will continue to remain responsive. We
                    have a setup quite similar to this... the UI runs in the main process
                    thread and the capture and subsequent download of data occurs in a
                    background thread. Despite the separation of work, the UI continues to
                    lockup when the ASCOM camera transfers data to the host computer. It
                    looks to us like the entire process (all threads) become unresponsive
                    when this happens.

                    There appears to be something we don't know about threading and
                    accessing hardware like USB ports...

                    Has anyone experienced anything like this?

                    We are using ASCOM 6, C# and .NET 4

                    Thanks for any help,
                    Ken



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                  • Bob Denny
                    Howard -- This is an ACP issue, and you can best handle it on the DC-3 Dreams Communications Center at http://forums.dc3.com/. While I appreciate the help
                    Message 9 of 26 , Feb 20, 2012
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                      Howard --

                      This is an ACP issue, and you can best handle it on the DC-3 Dreams Communications Center at http://forums.dc3.com/. While I appreciate the help being given here, it's a bit off base. The optec focuser works great with FocusMax. The filter offsets are not sup0posed to be set into MaxIm. ACP has its own filter focus offset system and an automagic script that measures and sets them up. Those are  the short answers. Feel free to call here as well.

                        -- Bob

                    • Jim Jones
                      Bob This is the issue that Tom Krajci brought up a year or so ago on the ACP/FocusMax forum. Tom has now implemented temp coef on the AAVSO telescopes using a
                      Message 10 of 26 , Feb 20, 2012
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                        Bob

                        This is the issue that Tom Krajci brought up a year or so ago on the
                        ACP/FocusMax forum. Tom has now implemented temp coef on the AAVSO
                        telescopes using a beta FocusMax (which I am going to try and get from
                        Steve Brady).

                        The issue isn't filter offsets but how to implement temperature
                        coefficients without losing the ability to use filter offsets. Since
                        neither ACP nor FocusMax (other than the beta) support temp coef the
                        only alternative is MaxIm.

                        I think this is an important issue. Most if not all of the research
                        telescopes that I am familiar with now either use a carbon tube or use
                        temp coefficients to avoid auto focusing. Pulling the telescope off the
                        target to periodically focus simply loses too much data.

                        When I am imaging double stars where a crisp focus is very important, I
                        still autofocus before each target.

                        I know you were talking to Howard, but I'll give you a call in the next
                        day or so. I need to get this solved before the next observing season
                        starts.

                        Jim Jones

                        Bob Denny wrote:
                        > Howard --
                        >
                        > This is an ACP issue, and you can best handle it on the DC-3 Dreams
                        > Communications Center at http://forums.dc3.com/. While I appreciate the help
                        > being given here, it's a bit off base. The optec focuser works great with
                        > FocusMax. The filter offsets are not sup0posed to be set into MaxIm. ACP has its
                        > own filter focus offset system and an automagic script that measures and sets
                        > them up. Those are the short answers. Feel free to call here as well.
                        >
                        > -- Bob
                        >
                        >
                        >
                      • Chris Peterson
                        It is worth keeping in mind that temperature compensation is extremely difficult to set up, because in most cases there is no determinate relationship between
                        Message 11 of 26 , Feb 20, 2012
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                          It is worth keeping in mind that temperature compensation is extremely
                          difficult to set up, because in most cases there is no determinate
                          relationship between ambient temperature and focus. Getting good results
                          requires making multiple temperature measurements, and characterizing
                          the unique aspects of the system. For most people, this will be close
                          enough to impossible to make it not worthwhile.

                          Temperature compensated focusing is open loop, and can never produce as
                          good of results as actively refocusing based on the image. Something is
                          very wrong if doing that is costing you significant imaging time. Often
                          it is unnecessary to even change the scope position, but even if you do,
                          it should not require more than a minute or so to refocus- and you are
                          guaranteed in doing so that you will actually be in focus. Open loop,
                          temperature compensated focusing can't do that.

                          Chris

                          *******************************
                          Chris L Peterson
                          Cloudbait Observatory
                          http://www.cloudbait.com

                          On 2/20/2012 9:27 PM, Jim Jones wrote:
                          > Bob
                          >
                          > This is the issue that Tom Krajci brought up a year or so ago on the
                          > ACP/FocusMax forum. Tom has now implemented temp coef on the AAVSO
                          > telescopes using a beta FocusMax (which I am going to try and get from
                          > Steve Brady).
                          >
                          > The issue isn't filter offsets but how to implement temperature
                          > coefficients without losing the ability to use filter offsets. Since
                          > neither ACP nor FocusMax (other than the beta) support temp coef the
                          > only alternative is MaxIm.
                          >
                          > I think this is an important issue. Most if not all of the research
                          > telescopes that I am familiar with now either use a carbon tube or use
                          > temp coefficients to avoid auto focusing. Pulling the telescope off the
                          > target to periodically focus simply loses too much data.
                          >
                          > When I am imaging double stars where a crisp focus is very important, I
                          > still autofocus before each target.
                          >
                          > I know you were talking to Howard, but I'll give you a call in the next
                          > day or so. I need to get this solved before the next observing season
                          > starts.
                          >
                          > Jim Jones
                          >
                        • Jim Jones
                          Arrgh...I just realized I was on the ASCOM forum.....I thought I just exchanging comments on how to solve a problem with another observer on the OpTec forum.
                          Message 12 of 26 , Feb 20, 2012
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                            Arrgh...I just realized I was on the ASCOM forum.....I thought I just
                            exchanging comments on how to solve a problem with another observer on
                            the OpTec forum. This really doesn't rise to the level of the ASCOM forum.

                            Anyway, I suspect that Chris is right when it comes to pretty picture
                            taking. However for photometry temperature compensation forks fine. I
                            took about 20,000 observations last summer...all using temperature
                            compensation. Tom Kracji runs 8 AAVSO telescopes and so far as I know,
                            all are using temperature compensation. So it does work.

                            I think a minute is optimistic when you have to slew the telescope to
                            the focus star, refocus, and slew back to the target and recenter the
                            target. Generally I am taking very long time series at as high of a
                            cadence as possible and want to avoid any breaks in the series if I
                            can....even a minute.

                            As I said, when I am making double star observations where accurate
                            astrometry is important, I refocus between each target.

                            Now I'll bow out of this discussion. Sorry about the mixup.

                            Jim Jones

                            Chris Peterson wrote:
                            > It is worth keeping in mind that temperature compensation is extremely
                            > difficult to set up, because in most cases there is no determinate
                            > relationship between ambient temperature and focus. Getting good results
                            > requires making multiple temperature measurements, and characterizing
                            > the unique aspects of the system. For most people, this will be close
                            > enough to impossible to make it not worthwhile.
                            >
                            > Temperature compensated focusing is open loop, and can never produce as
                            > good of results as actively refocusing based on the image. Something is
                            > very wrong if doing that is costing you significant imaging time. Often
                            > it is unnecessary to even change the scope position, but even if you do,
                            > it should not require more than a minute or so to refocus- and you are
                            > guaranteed in doing so that you will actually be in focus. Open loop,
                            > temperature compensated focusing can't do that.
                            >
                            > Chris
                            >
                            > *******************************
                            > Chris L Peterson
                            > Cloudbait Observatory
                            > http://www.cloudbait.com
                            >
                            > On 2/20/2012 9:27 PM, Jim Jones wrote:
                            >
                            >> Bob
                            >>
                            >> This is the issue that Tom Krajci brought up a year or so ago on the
                            >> ACP/FocusMax forum. Tom has now implemented temp coef on the AAVSO
                            >> telescopes using a beta FocusMax (which I am going to try and get from
                            >> Steve Brady).
                            >>
                            >> The issue isn't filter offsets but how to implement temperature
                            >> coefficients without losing the ability to use filter offsets. Since
                            >> neither ACP nor FocusMax (other than the beta) support temp coef the
                            >> only alternative is MaxIm.
                            >>
                            >> I think this is an important issue. Most if not all of the research
                            >> telescopes that I am familiar with now either use a carbon tube or use
                            >> temp coefficients to avoid auto focusing. Pulling the telescope off the
                            >> target to periodically focus simply loses too much data.
                            >>
                            >> When I am imaging double stars where a crisp focus is very important, I
                            >> still autofocus before each target.
                            >>
                            >> I know you were talking to Howard, but I'll give you a call in the next
                            >> day or so. I need to get this solved before the next observing season
                            >> starts.
                            >>
                            >> Jim Jones
                            >>
                            >>
                            >
                            >
                            > ------------------------------------
                            >
                            > For more information see http://ASCOM-Standards.org/.
                            >
                            > To unsubscribe from this group, send an email FROM THE ACCOUNT YOU USED TO SUBSCRIBE(!) to:
                            > ASCOM-Talk-unsubscribe@yahoogroups.com
                            >
                            > Yahoo! Groups Links
                            >
                            >
                            >
                            >
                            >
                          • dc3dreamer
                            I doubt whether the camera s Ascom-ness has anything to do with it. The problem (and bad solution) exists at a much lower level. Whether being used via the
                            Message 13 of 26 , Feb 20, 2012
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                              I doubt whether the camera's "Ascom-ness" has anything to do with it. The problem (and bad solution) exists at a much lower level. Whether being used via the MaxIm API or the ASCOM API is probably irrelevant.

                              -- Bob

                              --- In ASCOM-Talk@yahoogroups.com, "Ken" <kenpendlebury@...> wrote:
                              >
                              > Thanks for the feedback. We are getting reports of this behavior right now mostly for ASCOM cameras (Atik 8300 in particular). I am not sure if this behavior is present with the SBIG camera.
                            • Howard Anderson
                              Hi all, Sorry Bob. I have difficulty determining where ASCOM leaves off and ACP starts since ACP appears to be intertwined heavily with ASCOM so I am never
                              Message 14 of 26 , Feb 21, 2012
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                                Hi all,

                                Sorry Bob.  I have difficulty determining where ASCOM leaves off and ACP starts
                                since ACP appears to be intertwined heavily with ASCOM
                                so I am never sure where to post.  I assume by off base, you meant off topic.

                                I assumed the problem was not with ACP but with the ASCOM drivers that
                                perhaps didn't support what I wanted to do.  Or with FocusMax which
                                does not seem to be an ACP issue per se so I would have had no idea where
                                to discuss that. 

                                This will be my last transmission here on this topic.  Again, sorry if I posted
                                to the wrong area...

                                Chris and Jim:
                                Yes, characterizing the TCF-Si focuser does take some work but I generally take
                                a bunch of measurements in the early evening then take a bunch more just before dawn so
                                that I get a good temperature range.  The data below is for LRGB Astrodon filters and
                                my current setup.  You can't tell which are which here but the LRG and B values are
                                all  represented here and by looking at the original data for each I have determined
                                that each is as likely to be above the line as below the line so that they all are essentially parfocal
                                in my opinion.  The few images I have managed to take between cloudy weather
                                conditions seem to support that opinion. 

                                This is from my Excel spreadsheet:


                                Thanks,

                                Howard

                                Bob Denny wrote:
                                 

                                Howard --

                                This is an ACP issue, and you can best handle it on the DC-3 Dreams Communications Center at http://forums.dc3.com/. While I appreciate the help being given here, it's a bit off base. The optec focuser works great with FocusMax. The filter offsets are not sup0posed to be set into MaxIm. ACP has its own filter focus offset system and an automagic script that measures and sets them up. Those are  the short answers. Feel free to call here as well.

                                  -- Bob


                              • Gary
                                Howard I believe Yahoo stripped off your spreadsheet. Could you post it in the files section, and let us know what the name is? I would like to take a look
                                Message 15 of 26 , Feb 21, 2012
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                                  Howard

                                  I believe Yahoo stripped off your spreadsheet. Could you post it in the files section, and let us know what the name is? I would like to take a look at it.

                                  Thanks
                                  Gary W



                                  --- In ASCOM-Talk@yahoogroups.com, Howard Anderson <handy13@...> wrote:
                                  >
                                  > Hi all,
                                  >
                                  > Sorry Bob. I have difficulty determining where ASCOM leaves off and ACP
                                  > starts
                                  > since ACP appears to be intertwined heavily with ASCOM
                                  > so I am never sure where to post. I assume by off base, you meant off
                                  > topic.
                                  >
                                  > I assumed the problem was not with ACP but with the ASCOM drivers that
                                  > perhaps didn't support what I wanted to do. Or with FocusMax which
                                  > does not seem to be an ACP issue per se so I would have had no idea where
                                  > to discuss that.
                                  >
                                  > This will be my last transmission here on this topic. Again, sorry if I
                                  > posted
                                  > to the wrong area...
                                  >
                                  > Chris and Jim:
                                  > Yes, characterizing the TCF-Si focuser does take some work but I
                                  > generally take
                                  > a bunch of measurements in the early evening then take a bunch more just
                                  > before dawn so
                                  > that I get a good temperature range. The data below is for LRGB
                                  > Astrodon filters and
                                  > my current setup. You can't tell which are which here but the LRG and B
                                  > values are
                                  > all represented here and by looking at the original data for each I
                                  > have determined
                                  > that each is as likely to be above the line as below the line so that
                                  > they all are essentially parfocal
                                  > in my opinion. The few images I have managed to take between cloudy weather
                                  > conditions seem to support that opinion.
                                  >
                                  > This is from my Excel spreadsheet:
                                  >
                                  >
                                  > Thanks,
                                  >
                                  > Howard
                                  >
                                  > Bob Denny wrote:
                                  >
                                  > >
                                  > >
                                  > > Howard --
                                  > >
                                  > > This is an ACP issue, and you can best handle it on the DC-3 Dreams
                                  > > Communications Center at http://forums.dc3.com/. While I appreciate
                                  > > the help being given here, it's a bit off base. The optec focuser
                                  > > works great with FocusMax. The filter offsets are not sup0posed to be
                                  > > set into MaxIm. ACP has its own filter focus offset system and an
                                  > > automagic script that measures and sets them up. Those are the short
                                  > > answers. Feel free to call here as well.
                                  > >
                                  > > -- Bob
                                  > >
                                  > >
                                  >
                                • Jim Jones
                                  OK this really is my last, last word. At least for a C14 Classic OTA, the temperature coefficient doesn t seem that difficult. Jeff Dickerson of OpTec
                                  Message 16 of 26 , Feb 21, 2012
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                                    OK this really is my last, last word.

                                    At least for a C14 Classic OTA, the temperature coefficient doesn't seem
                                    that difficult. Jeff Dickerson of OpTec determined the temp coef of a
                                    C14 and posted it in the files section of the FocusMax forum. I just
                                    used his value for my C14 and it worked fine....at least over summer
                                    temp ranges.

                                    Jim Jones



                                    Howard Anderson wrote:
                                    > Hi all,
                                    >
                                    > Sorry Bob. I have difficulty determining where ASCOM leaves off and ACP starts
                                    > since ACP appears to be intertwined heavily with ASCOM
                                    > so I am never sure where to post. I assume by off base, you meant off topic.
                                    >
                                    > I assumed the problem was not with ACP but with the ASCOM drivers that
                                    > perhaps didn't support what I wanted to do. Or with FocusMax which
                                    > does not seem to be an ACP issue per se so I would have had no idea where
                                    > to discuss that.
                                    >
                                    > This will be my last transmission here on this topic. Again, sorry if I posted
                                    > to the wrong area...
                                    >
                                    > Chris and Jim:
                                    > Yes, characterizing the TCF-Si focuser does take some work but I generally take
                                    > a bunch of measurements in the early evening then take a bunch more just before
                                    > dawn so
                                    > that I get a good temperature range. The data below is for LRGB Astrodon
                                    > filters and
                                    > my current setup. You can't tell which are which here but the LRG and B values are
                                    > all represented here and by looking at the original data for each I have determined
                                    > that each is as likely to be above the line as below the line so that they all
                                    > are essentially parfocal
                                    > in my opinion. The few images I have managed to take between cloudy weather
                                    > conditions seem to support that opinion.
                                    >
                                    > This is from my Excel spreadsheet:
                                    >
                                    >
                                    > Thanks,
                                    >
                                    > Howard
                                    >
                                    > Bob Denny wrote:
                                    > >
                                    > >
                                    > > Howard --
                                    > >
                                    > > This is an ACP issue, and you can best handle it on the DC-3 Dreams
                                    > > Communications Center at http://forums.dc3.com/. While I appreciate the help
                                    > > being given here, it's a bit off base. The optec focuser works great with
                                    > > FocusMax. The filter offsets are not sup0posed to be set into MaxIm. ACP has
                                    > > its own filter focus offset system and an automagic script that measures and
                                    > > sets them up. Those are the short answers. Feel free to call here as well.
                                    > >
                                    > > -- Bob
                                    > >
                                    >
                                    >
                                  • Chris Peterson
                                    What does temperature coefficient mean? Are you talking about a high quality sensor carefully coupled to some part of the OTA? Because there is no possible
                                    Message 17 of 26 , Feb 21, 2012
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                                      What does "temperature coefficient" mean? Are you talking about a high
                                      quality sensor carefully coupled to some part of the OTA? Because there
                                      is no possible temp coefficient that can be based on the ambient air
                                      temperature, and different parts of the OTA will have different
                                      temperatures.

                                      The only way I was ever able to get good results with temperature
                                      compensated focusing was by looking a the air temperature, the
                                      temperature on the top and bottom of my OTA itself, and the sky
                                      temperature. Those (and their derivatives) went into a high-order
                                      polynomial, and out popped the focus position. Worked pretty well- but
                                      still not as good as closed-looped focusing.

                                      I'd say you got lucky!

                                      Chris

                                      *******************************
                                      Chris L Peterson
                                      Cloudbait Observatory
                                      http://www.cloudbait.com

                                      On 2/21/2012 10:12 AM, Jim Jones wrote:
                                      > OK this really is my last, last word.
                                      >
                                      > At least for a C14 Classic OTA, the temperature coefficient doesn't seem
                                      > that difficult. Jeff Dickerson of OpTec determined the temp coef of a
                                      > C14 and posted it in the files section of the FocusMax forum. I just
                                      > used his value for my C14 and it worked fine....at least over summer
                                      > temp ranges.
                                      >
                                      > Jim Jones
                                      >
                                    • Tim Long
                                      Chris, my experience tallies with yours and I prefer to refocus regularly, but sometimes things work *in spite of* theories that say it shouldn t. You can t
                                      Message 18 of 26 , Feb 21, 2012
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                                        Chris, my experience tallies with yours and I prefer to refocus
                                        regularly, but sometimes things work *in spite of* theories that say it
                                        shouldn't. You can't argue with results. Temperature compensation
                                        clearly works for *some* people some of the time.

                                        --Tim

                                        -----Original Message-----
                                        From: ASCOM-Talk@yahoogroups.com [mailto:ASCOM-Talk@yahoogroups.com] On
                                        Behalf Of Chris Peterson
                                        Sent: 21 February 2012 17:38
                                        To: ASCOM-Talk@yahoogroups.com
                                        Subject: Re: [ASCOM] TCF-Si Focuser and ACP Autofocus

                                        What does "temperature coefficient" mean? Are you talking about a high
                                        quality sensor carefully coupled to some part of the OTA? Because there
                                        is no possible temp coefficient that can be based on the ambient air
                                        temperature, and different parts of the OTA will have different
                                        temperatures.

                                        The only way I was ever able to get good results with temperature
                                        compensated focusing was by looking a the air temperature, the
                                        temperature on the top and bottom of my OTA itself, and the sky
                                        temperature. Those (and their derivatives) went into a high-order
                                        polynomial, and out popped the focus position. Worked pretty well- but
                                        still not as good as closed-looped focusing.

                                        I'd say you got lucky!

                                        Chris

                                        *******************************
                                        Chris L Peterson
                                        Cloudbait Observatory
                                        http://www.cloudbait.com

                                        On 2/21/2012 10:12 AM, Jim Jones wrote:
                                        > OK this really is my last, last word.
                                        >
                                        > At least for a C14 Classic OTA, the temperature coefficient doesn't
                                        > seem that difficult. Jeff Dickerson of OpTec determined the temp coef

                                        > of a
                                        > C14 and posted it in the files section of the FocusMax forum. I just
                                        > used his value for my C14 and it worked fine....at least over summer
                                        > temp ranges.
                                        >
                                        > Jim Jones
                                        >


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                                      • Bob Denny
                                        Howard -- I m sorry if I came off harsh. I just wanted to address this on the ACP forum because it is an ACP issue. The only connection between ACP and ASCOM
                                        Message 19 of 26 , Feb 21, 2012
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                                          Howard --

                                          I'm sorry if I came off harsh. I just wanted to address this on the ACP forum because it is an ACP issue. The only connection between ACP and ASCOM is that ACP, like MaxIm and other programs, uses ASCOM drivers.

                                          With ACP, there is an automated script that measures filter offsets and stores them in a config file. The filter offsets in MaxIm are not used (and should be zero for ACP use). You can set things up for ACP then store that MaxIm configuration in a "configuration" in case yu use MaxIm for manual things that use different settings.

                                            -- Bob

                                          You said:
                                          Hi all,

                                          Sorry Bob.  I have difficulty determining where ASCOM leaves off and ACP starts
                                          since ACP appears to be intertwined heavily with ASCOM
                                          so I am never sure where to post.  I assume by off base, you meant off topic.

                                          I assumed the problem was not with ACP but with the ASCOM drivers that
                                          perhaps didn't support what I wanted to do.  Or with FocusMax which
                                          does not seem to be an ACP issue per se so I would have had no idea where
                                          to discuss that. 

                                          This will be my last transmission here on this topic.  Again, sorry if I posted
                                          to the wrong area...

                                          Chris and Jim:
                                          Yes, characterizing the TCF-Si focuser does take some work but I generally take
                                          a bunch of measurements in the early evening then take a bunch more just before dawn so
                                          that I get a good temperature range.  The data below is for LRGB Astrodon filters and
                                          my current setup.  You can't tell which are which here but the LRG and B values are
                                          all  represented here and by looking at the original data for each I have determined
                                          that each is as likely to be above the line as below the line so that they all are essentially parfocal
                                          in my opinion.  The few images I have managed to take between cloudy weather
                                          conditions seem to support that opinion. 

                                          This is from my Excel spreadsheet:


                                          Thanks,

                                          Howard

                                          Bob Denny wrote:
                                           

                                          Howard --

                                          This is an ACP issue, and you can best handle it on the DC-3 Dreams Communications Center at http://forums.dc3.com/. While I appreciate the help being given here, it's a bit off base. The optec focuser works great with FocusMax. The filter offsets are not sup0posed to be set into MaxIm. ACP has its own filter focus offset system and an automagic script that measures and sets them up. Those are  the short answers. Feel free to call here as well.

                                            -- Bob




                                        • Chris Peterson
                                          Agreed. And it often works better than no refocusing at all, even if that s worse than closed loop focusing. And that may be good enough... especially for
                                          Message 20 of 26 , Feb 21, 2012
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                                            Agreed. And it often works better than no refocusing at all, even if
                                            that's worse than closed loop focusing. And that may be good enough...
                                            especially for things like photometry and astrometry that don't usually
                                            require as tight of focus as aesthetic imaging.

                                            Chris

                                            *******************************
                                            Chris L Peterson
                                            Cloudbait Observatory
                                            http://www.cloudbait.com

                                            On 2/21/2012 2:39 PM, Tim Long wrote:
                                            > Chris, my experience tallies with yours and I prefer to refocus
                                            > regularly, but sometimes things work *in spite of* theories that say it
                                            > shouldn't. You can't argue with results. Temperature compensation
                                            > clearly works for *some* people some of the time.
                                            >
                                            > --Tim
                                            >
                                            >
                                          • Jim Jones
                                            Guys, this is starting to resemble the bumble bee that can t fly. Professional telescopes in the 1 meter class have been focusing by temp compensation for
                                            Message 21 of 26 , Feb 21, 2012
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                                              Guys, this is starting to resemble the bumble bee that can't fly.

                                              Professional telescopes in the 1 meter class have been focusing by temp
                                              compensation for quite a while. OpTec hardware and drivers support
                                              temperature coefficients. Their focusers come with a probe that is
                                              mounted on the OTA. MaxIm supports temperature coefficients.

                                              I have no idea if it would work for "aesthetic imaging" (I assume that
                                              is the same as purty pictures?). But it works for me and many others
                                              doing science.

                                              And this really is the last, last, last word.

                                              Jim Jones



                                              Chris Peterson wrote:
                                              > Agreed. And it often works better than no refocusing at all, even if
                                              > that's worse than closed loop focusing. And that may be good enough...
                                              > especially for things like photometry and astrometry that don't usually
                                              > require as tight of focus as aesthetic imaging.
                                              >
                                              > Chris
                                              >
                                              > *******************************
                                              > Chris L Peterson
                                              > Cloudbait Observatory
                                              > http://www.cloudbait.com
                                              >
                                              > On 2/21/2012 2:39 PM, Tim Long wrote:
                                              >
                                              >> Chris, my experience tallies with yours and I prefer to refocus
                                              >> regularly, but sometimes things work *in spite of* theories that say it
                                              >> shouldn't. You can't argue with results. Temperature compensation
                                              >> clearly works for *some* people some of the time.
                                              >>
                                              >> --Tim
                                              >>
                                              >>
                                              >>
                                              >
                                              >
                                              > ------------------------------------
                                              >
                                              > For more information see http://ASCOM-Standards.org/.
                                              >
                                              > To unsubscribe from this group, send an email FROM THE ACCOUNT YOU USED TO SUBSCRIBE(!) to:
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                                              >
                                            • Gary
                                              Hello It is true that Professional telescopes in the 1 meter class have been focusing by temp compensation for quite a while. I once had a conversation with Dr
                                              Message 22 of 26 , Feb 21, 2012
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                                                Hello

                                                It is true that Professional telescopes in the 1 meter class have been focusing by temp compensation for quite a while.

                                                I once had a conversation with Dr Arne Henden of the AAVSO about this. First, the main trick to this is to locate the temp probe in the optimum place. He told me that what most Professional Telescopes do when they are setting this up, is they locate about 20 thermocouples all over the scope. They then measure these temps and the focus position and choose the best location for the probe.

                                                Perhaps why some are getting it to work, is that they have a better temp probe location?

                                                I got lucky and developed a carbon tube to match my scope's tempco and it works very well. Yet there are those who claim that carbon tubes do not work at all. It depends on the type of scope you have and how you implement it--its called Engineering.

                                                Gary W.





                                                --- In ASCOM-Talk@yahoogroups.com, Jim Jones <albiero@...> wrote:
                                                >
                                                > Guys, this is starting to resemble the bumble bee that can't fly.
                                                >
                                                > Professional telescopes in the 1 meter class have been focusing by temp
                                                > compensation for quite a while. OpTec hardware and drivers support
                                                > temperature coefficients. Their focusers come with a probe that is
                                                > mounted on the OTA. MaxIm supports temperature coefficients.
                                                >
                                                > I have no idea if it would work for "aesthetic imaging" (I assume that
                                                > is the same as purty pictures?). But it works for me and many others
                                                > doing science.
                                                >
                                                > And this really is the last, last, last word.
                                                >
                                                > Jim Jones
                                                >
                                                >
                                                >
                                                > Chris Peterson wrote:
                                                > > Agreed. And it often works better than no refocusing at all, even if
                                                > > that's worse than closed loop focusing. And that may be good enough...
                                                > > especially for things like photometry and astrometry that don't usually
                                                > > require as tight of focus as aesthetic imaging.
                                                > >
                                                > > Chris
                                                > >
                                                > > *******************************
                                                > > Chris L Peterson
                                                > > Cloudbait Observatory
                                                > > http://www.cloudbait.com
                                                > >
                                                > > On 2/21/2012 2:39 PM, Tim Long wrote:
                                                > >
                                                > >> Chris, my experience tallies with yours and I prefer to refocus
                                                > >> regularly, but sometimes things work *in spite of* theories that say it
                                                > >> shouldn't. You can't argue with results. Temperature compensation
                                                > >> clearly works for *some* people some of the time.
                                                > >>
                                                > >> --Tim
                                                > >>
                                                > >>
                                                > >>
                                                > >
                                                > >
                                                > > ------------------------------------
                                                > >
                                                > > For more information see http://ASCOM-Standards.org/.
                                                > >
                                                > > To unsubscribe from this group, send an email FROM THE ACCOUNT YOU USED TO SUBSCRIBE(!) to:
                                                > > ASCOM-Talk-unsubscribe@yahoogroups.com
                                                > >
                                                > > Yahoo! Groups Links
                                                > >
                                                > >
                                                > >
                                                > >
                                                > >
                                                >
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