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  1. #1

    Default First run with imaging script - Outstanding issues

    Bob,

    Last night was the first time I ran an imaging script (uploaded). The target was NGC6992, part of the Veil complex. There are several issues that I still need to resolve.

    1. In the initial focus run, the first exposure is 30 sec. I am more used to a short exposure to determine the bright star.
    2. In the initial GoTo, the rotator is adjusted to the position in the script. When is focuses after that, the rotator is moving again. I have not seen that before.
    3. I can't get the guider to work properly. I ran the guider adjustment script, but it will not guide as expected. So this run was done unguided.
    4. The most puzzling thing is that when the script calls for another focus, the guider once again rotates to some position or another. That means that every 90 minutes I get a new field rotation, not the one called for in the script. The result is that I have three different rotation angles in my subs. I have uploaded an example of each.
    5. I also uploaded the log file.

    These are probably simple changes and I would appreciate it if you could login and show me what to do. Thanks in advance.

    Eric
    Attached Images Attached Images
    Attached Files Attached Files

  2. #2
    Join Date
    Oct 2005
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    Mesa, AZ
    Posts
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    Excellent and thank you for the first class post, attached logs, and inline images included! You're gettin' it! OK:

    1. In the initial focus run, the first exposure is 30 sec. I am more used to a short exposure to determine the bright star.
    Are you referring to this?:

    04:33:16 Doing auto-center...
    04:33:16 (taking 30 sec. exposure, L filter, binning = 3)

    If so, this is the exposure ACP is taking for the pointing update to center the scope on the selected focus star before starting FocusMax. I agree it's long for your setup. We talked about it and decided to leave it till we saw what the results were:

    04:33:53 4684 image stars found
    04:33:53 674 catalog stars found
    04:33:54 Solved! 183 stars matched.

    Yeah, 30 sec is more than long enough! Change it to 10 for starters. ACP Preferences > PinPoint & All Sky > Pointing Updates section > Exp Interval -> 10.

    2. In the initial GoTo, the rotator is adjusted to the position in the script. When is focuses after that, the rotator is moving again. I have not seen that before.
    04:33:16 Doing auto-center...
    [...]
    04:33:54 Solved! 183 stars matched.
    [...]
    04:33:54 PA error of 177.4 deg. detected. Correcting...
    04:33:54 Start rotate to PA 255.0 deg (raw rotator angle 186.9)
    04:33:54 (wait for rotator)
    04:35:51 (rotation complete)

    This is ACP determining that your camera is mounted at a 177 deg offset from the angle being reported by the rotator, then correcting the rotation to achieve your requested Sky Position Angle of 255. Basically the camera is more or less upside down in the rotator. No big deal, ACP will just deal with it from now on. But I see an issue:

    04:38:31 Imager sky position angle is 260.2 deg.
    04:38:31 Rotator mech. position angle is 186.9 deg.
    04:38:31 Within max error tolerance, no re-slew needed.
    04:38:31 [high]PA error of 5.2 deg. detected. Correcting...
    04:38:31 Start rotate to PA 255.0 deg (raw rotator angle 181.7)
    04:38:31 (wait for rotator)
    04:38:35 (rotation complete)

    You should not see any more "PA Error..." messages in the log. But there is another 5 degrees error after the last correction. It is 100% certain that the rotator is not working quite right. You'll need to check for rotator looseness, insufficient power (cogging), or cable snags. Until it always rotates to the requested angle (it missed by 5 degrees this time) you'll go crazy trying to "get" a guide star. This is a new installation, so I will make a bet on it being loose, and this is hazardous for your camera!


    3. I can't get the guider to work properly. I ran the guider adjustment script, but it will not guide as expected. So this run was done unguided.
    Is it possible that the rotator missed and there wasn't a good guide star in the field? If that's not it, and there was a good solid guide star in the field, then Something in the bumping isn't set right. Before I log in at night to solve this, let's try some things. Assuming the CalibrateGuider script ran OK, and you haven't made any changes manually to the guider scales and angle, I'm going to guess that the guide sensor angle is OK. If your rotator only missed by a little bit, it will still probably be "close enough". However if your rotator missed by a lot, then that guide sensor angle would be measured so far off that it would affect guiding. You don't have a GEM so several other sources of error are not present (yay!). If I could see a log of an attempted run with guiding I might be able to make sense. At a minimum, see if you can get the rotator to be consistent, then re-do the guider calibration. Keep in mind that this is a one-time process until you disassemble the system. Well until you get it to work heh heh.


    4. The most puzzling thing is that when the script calls for another focus, the guider once again rotates to some position or another. That means that every 90 minutes I get a new field rotation, not the one called for in the script. The result is that I have three different rotation angles in my subs. I have uploaded an example of each.
    Yeah, this is what I mean. Job #1 is to get that rotator to behave. That's going to affect everything. Use a test plan of 8 targets at 8 angles without trying to guide. Just take 30 sec images at 10 angles. For example (19H RA near meridian at 10PM at night there):


    Code:
    ;
    ; Plan to check rotator accuracy and repeatability
    ;
    #interval 30
    #binning 2  ; just to save time
    #filter V
    #posang 0
    Test-0<tab>19<tab>55
    #posang 180
    Test-180<tab>19<tab>55
    #posang 90
    Test-90<tab>19<tab>55
    #posang 270
    Test-270<tab>19<tab>55
    #posang 45
    Test-45<tab>19<tab>55
    #posang 225
    Test-225<tab>19<tab>55
    #posang 135
    Test-135<tab>19<tab>55
    #posang 325
    Test-325<tab>19<tab>55
    I have attached this plan as a file ready to run under AcquireImages... Thank you forever for the logs. The ACP run log provided the key to some or all of the problems
    Attached Files Attached Files
    -- Bob

  3. #3

    Default

    Thanks Bob,

    I had Evan go to the mount to check for any cable problems. All looked good to him. I also exercised the rotator and set it back to zero. Your test file is downloaded. How do I run it from the ACP main window? It is odd that the rotator might be the problem. It has been operating perfectly for the past year. And I am still not grasping why ACP put the rotator in a different orientation each time it focused. The first position was the one that I planned in Guide9.

    I watched the guider image. There were plenty of decent guide stars. The issue was the guiding itself. On the guide Graph window both the X and Y axis seemed to plateau above and below the zero axis.Guider Graph.jpg and didn't look like they were returning to zero or like the signals sent to the mount were having any effect. I don't understand that behavior. And it's not like anything I have seen with other mounts.

    I will be trying the same target tonight. The fun begins around 8:30. You are certainly welcome to join.

    Eric

  4. #4
    Join Date
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    Run my observing plan just like any other observing plan. Put it into your folder of Plans, load AcquireImages, press Run, select my test plan, and let it go. Save and post back here with the log. I will be able to tell a lot.

    I work at this all day 5-6 days a week, and I've really been working to get out this upcoming release, plus I am usually up at 0430. It would be fun to watch but I need some time off every day. If it comes to that, though, we can set up a time then I will adjust my schedule to accommodate that.

    On the guiding it may indeed be needed. It will need to be next week though. Sat and Sun nights are not work nights for me. I hope you understand.
    -- Bob

  5. #5

    Default

    Bob,

    I ran last night and these are the results.
    1. I tried running your rotation script and just got errors. Not sure what the issue is, but I am uploading the log file.
    2. I ran unguided NGC6992_RGB and again got these rotated subs.
    3. I recalibrated the guider and that went well. But even in Maxim I couldn't guide. This has to be a mount issue.
    If you can address this on Monday I would appreciate it.
    Thanks.

    Eric
    Attached Files Attached Files

  6. #6

    Default Update

    Bob,

    I ran again last night and these are the results.

    1. I uploaded the log file.
    2. I got guiding running. It was the settings in Maxim that were the issue. This is good news.
    3. I am puzzled about the initial changes in the rotator. I am used to the rotator coming to the correct position and that is it for the entire run. As I watched the start of the run, the rotator came to the correct position and then had to rotate again for the focus run and again when it went back to the target.
    4. There were three different orientations for last nights subs. I have uploaded an example of each. I thinks these are occurring during the periodic focus runs. If this is an issue with the rotator or the mount, I can have Sam or Evan check on it today. If you can give me some guidance that would be helpful.

    I am available most times today. Let me know what would be best for you.

    Thanks.

    Eric
    Attached Images Attached Images
    Attached Files Attached Files

  7. #7
    Join Date
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    Default

    1. I tried running your rotation script and just got errors. Not sure what the issue is, but I am uploading the log file.
    The log was for NGC6992 not for the rotator test. Not a problem, your run and its log tells me everything I need to know anyway. See the rotator analysis below.

    Some comments on the log you did provide:

    Pointing Errors Analysis:

    03:54:33 Pointing error is 2.875 arcmin @ angle 100.31
    03:57:14 Pointing error is 2.742 arcmin @ angle 102.00
    04:03:40 Pointing error is 2.435 arcmin @ angle 96.73
    04:09:37 Pointing error is 2.853 arcmin @ angle 96.87
    04:15:32 Pointing error is 3.262 arcmin @ angle 96.87
    04:21:36 Pointing error is 3.722 arcmin @ angle 97.46
    04:27:43 Pointing error is 4.105 arcmin @ angle 95.93
    04:33:38 Pointing error is 4.460 arcmin @ angle 95.45
    04:39:37 Pointing error is 4.813 arcmin @ angle 94.76
    04:45:38 Pointing error is 5.301 arcmin @ angle 95.07
    04:51:42 Pointing error is 0.802 arcmin @ angle 90.47
    04:57:37 Pointing error is 1.237 arcmin @ angle 93.17
    05:03:37 Pointing error is 1.609 arcmin @ angle 93.30
    05:09:32 Pointing error is 2.058 arcmin @ angle 91.99
    05:15:38 Pointing error is 2.515 arcmin @ angle 93.15
    05:21:44 Pointing error is 3.014 arcmin @ angle 91.25
    05:27:37 Pointing error is 3.390 arcmin @ angle 91.99
    05:33:32 Pointing error is 3.843 arcmin @ angle 91.57
    05:39:37 Pointing error is 4.251 arcmin @ angle 92.52
    05:45:39 Pointing error is 4.691 arcmin @ angle 91.49
    05:51:42 Pointing error is 5.164 arcmin @ angle 90.56
    05:57:41 Pointing error is 0.928 arcmin @ angle 87.94
    05:58:27 Pointing error is 2.096 arcmin @ angle 109.46
    06:02:02 Pointing error is 2.036 arcmin @ angle 70.19
    06:09:45 Pointing error is 4.391 arcmin @ angle 90.59
    06:15:39 Pointing error is 4.836 arcmin @ angle 91.58
    06:21:39 Pointing error is 5.333 arcmin @ angle 91.61
    06:27:52 Pointing error is 0.888 arcmin @ angle 95.75
    06:33:48 Pointing error is 1.353 arcmin @ angle 94.77
    06:34:35 Pointing error is 3.800 arcmin @ angle 91.62
    06:37:28 Pointing error is 4.047 arcmin @ angle 81.70
    06:44:14 Pointing error is 3.535 arcmin @ angle 71.65
    06:50:10 Pointing error is 3.960 arcmin @ angle 73.39
    06:56:10 Pointing error is 4.374 arcmin @ angle 75.75
    07:02:16 Pointing error is 4.807 arcmin @ angle 76.19
    07:08:16 Pointing error is 5.125 arcmin @ angle 77.32
    07:14:18 Pointing error is 0.787 arcmin @ angle 96.61
    07:20:11 Pointing error is 1.217 arcmin @ angle 97.63
    07:26:24 Pointing error is 1.692 arcmin @ angle 94.86
    07:32:21 Pointing error is 2.030 arcmin @ angle 93.32
    07:38:25 Pointing error is 2.408 arcmin @ angle 91.68
    07:44:17 Pointing error is 2.786 arcmin @ angle 93.65
    07:50:31 Pointing error is 3.272 arcmin @ angle 93.99
    07:56:37 Pointing error is 3.661 arcmin @ angle 93.57
    08:02:31 Pointing error is 4.016 arcmin @ angle 92.82
    08:08:35 Pointing error is 4.472 arcmin @ angle 91.89
    08:14:39 Pointing error is 4.805 arcmin @ angle 91.79
    08:20:42 Pointing error is 5.266 arcmin @ angle 91.77
    08:26:53 Pointing error is 0.784 arcmin @ angle 88.95
    08:33:03 Pointing error is 1.176 arcmin @ angle 93.21
    08:38:58 Pointing error is 1.564 arcmin @ angle 93.31
    08:39:45 Pointing error is 2.583 arcmin @ angle 67.27
    08:43:46 Pointing error is 2.335 arcmin @ angle 111.85
    08:50:38 Pointing error is 2.141 arcmin @ angle 78.17
    08:56:34 Pointing error is 2.499 arcmin @ angle 81.58
    09:02:28 Pointing error is 2.939 arcmin @ angle 83.11
    09:08:26 Pointing error is 3.315 arcmin @ angle 85.23
    09:14:34 Pointing error is 3.703 arcmin @ angle 85.03
    09:15:17 Pointing error is 1.479 arcmin @ angle 77.86
    09:19:36 Pointing error is 3.683 arcmin @ angle 86.66
    09:26:18 Pointing error is 3.662 arcmin @ angle 75.31
    09:32:14 Pointing error is 3.994 arcmin @ angle 77.78
    09:38:26 Pointing error is 4.483 arcmin @ angle 78.62
    09:44:20 Pointing error is 4.972 arcmin @ angle 78.87
    09:50:19 Pointing error is 5.471 arcmin @ angle 79.94
    09:56:21 Pointing error is 0.919 arcmin @ angle 92.68
    10:02:21 Pointing error is 1.356 arcmin @ angle 90.11
    10:08:16 Pointing error is 1.861 arcmin @ angle 87.73
    10:14:21 Pointing error is 2.386 arcmin @ angle 86.64
    10:20:15 Pointing error is 2.841 arcmin @ angle 88.18
    10:26:11 Pointing error is 3.393 arcmin @ angle 87.88
    10:32:15 Pointing error is 3.864 arcmin @ angle 88.28
    10:38:09 Pointing error is 4.346 arcmin @ angle 88.76
    10:44:05 Pointing error is 4.795 arcmin @ angle 89.30
    10:50:09 Pointing error is 5.289 arcmin @ angle 90.25
    10:56:25 Pointing error is 0.993 arcmin @ angle 91.48
    11:02:28 Pointing error is 1.471 arcmin @ angle 92.93

    The pointing error is quite large for that direct drive mount with encoders. It should be sub-arc-minute all night. Note that we set the Max Pointing Error in ACP to 5 arc minutes, so as designed, the error increased to 5 arc-minutes and ACP did a resync of the mount seven times in six hours.

    08:20:42 Pointing error is 5.266 arcmin @ angle 91.77

    ...
    08:20:48 Re-slew to target.
    08:20:48 Start slew to NGC6992 RGB...
    08:20:49 (wait for slew to complete)
    08:20:53 (slew complete)
    ...
    08:26:53 Pointing error is 0.784 arcmin @ angle 88.95

    This is excessive. Something isn't right with the mount. Because you ran this unguided it has exposed a sidereal tracking issue. It is not tracking at the correct rate. Look at the angles on the pointing errors. These are angles on the sky, not relative to the camera rotation. So the mount is failing to keep up with the earth's rotation, thus its pointing is off more and more east (where things rise, right?) until it has to be resynced. This should be reported to Planewave. They should (will) make it right. It's probably an adjustment.

    Rotation Analysis:

    03:54:33 PA error of 20.4 deg. detected. Correcting...
    03:57:14 PA error of 40.8 deg. detected. Correcting...
    06:02:02 PA error of 162.3 deg. detected. Correcting...
    06:37:28 PA error of 70.8 deg. detected. Correcting...
    08:43:46 PA error of 76.0 deg. detected. Correcting...
    09:19:36 PA error of 56.1 deg. detected. Correcting...

    The rotator is absolutely positively not completing its commanded rotations. For whatever reason, when told to go to a specific mechanical angle, it is not going there. For example:

    03:50:21 Start rotate to PA 255.0 deg (raw rotator angle 171.8)
    ...
    03:54:33 Imager sky position angle is 275.4 deg.
    03:54:33 Rotator mech. position angle is 171.8 deg.
    03:54:33 Within max error tolerance, no re-slew needed.
    03:54:33 PA error of 20.4 deg. detected. Correcting...
    03:54:33 Start rotate to PA 255.0 deg (raw rotator angle 151.4)
    ... autofocus does not touch rotator ...
    03:57:14 Imager sky position angle is 295.8 deg.
    03:57:14 Rotator mech. position angle is 151.4 deg.
    03:57:14 Within max error tolerance, no re-slew needed.
    03:57:14 PA error of 40.8 deg. detected. Correcting...
    03:57:14 Start rotate to PA 255.0 deg (raw rotator angle 110.6)

    The first image of the plan, NGC6992, used the mechanical-sky offset of the rotator from the last run so it thought it needed to go to 171.8 on the rotator in order to get your requested 255 sky PA. It did that. Then it took an image and measured the real PA. It was not 255 , it was 274.4, 20.4 degrees off. Now it has another value for the mechanical versus sky angles, and re-rotates to again try to get the 255 des Sky PA, this time it thinks it needs to go to 151.4 on the rotator. Then it does an autofocus (not touching the rotator!!) and then takes the next image. Once again the PA is not the requested 255 degrees, it is 295.8. The rotator again failed to rotate as commanded. At 09:20 UTC something strange happened:

    09:19:36 PA error of 56.1 deg. detected. Correcting...
    09:19:36 Start rotate to PA 255.0 deg (raw rotator angle 303.4)
    ...
    09:26:18 Imager sky position angle is 142.8 deg.
    09:26:18 Rotator mech. position angle is 303.4 deg.
    ...

    09:38:26 Imager sky position angle is 142.8 deg.
    09:38:26 Rotator mech. position angle is 303.4 deg.
    ... etc


    Is it possible that this group of images does not have a #posang directive? It is happy to see 148 Sky PA yet you have been requesting 255.

    I hope I have explained this clearly enough so that there is no question that the rotator is not working right. I won't learn anything by logging onto the system until these problems are corrected.
    Last edited by Bob Denny; Sep 10, 2018 at 17:09. Reason: remove spurious blank lines
    -- Bob

  8. #8

    Default

    Thanks Bob. I will talk to Jeff at Optec and see what he has to say. Can we give him access to this thread so he can see what is going on?

  9. #9
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    I enabled Jeff's account (his license expired) but I'd bet he forgot his login info. I can't see his password. How about this? He can call me any time (always) and I can help him with data on this. But basically the rotator isn't completing it's requested operations. In any case I would check (in this order, and he will ask you to look at as many as you can):

    1. The camera package is really in there tight and unable to slip.
    2. The power supply running the rotator has enough voltage under full load (max current).
    3. There is no possibility of cables adding to the load of the rotator (pulling etc).
    4. Finally, is the camera package too heavy for the rotator's ability? Could it be overloaded?


    Don't forget about the other issue, the sidereal rate on the mount.
    -- Bob

  10. #10

    Default

    Thanks for giving me access to this thread. It looks like Eric has old firmware on his Gemini hub. That may or may not be the source of his rotator failing to home properly. Either way, my plan is to get his firmware updated and see if we can properly home the rotator.

    Will keep you in the loop on this - thanks again,

    Jeff.

 

 

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