Resolved Selecting Wrong Filter

Discussion in 'STX and STXL Series Cameras' started by Mark de Regt, Aug 12, 2020.

  1. Mark de Regt

    Mark de Regt Cyanogen Customer

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    Hi,

    I have an SBIG STX-16803/Ultimage Package.

    Lately, it has started imaging through the wrong filter when it's supposed to be imaging through a NB filter. I says it's an NB image when it's done; the FITS header says it's an NB image, but I can easily tell that it's not an NB image (they generally seem to be green or blue broadband, judging from the star size and how much of the nebula comes through). it is doing this more often than not, but not always.

    I can find no pattern. I carefully check my imaging plan (I use APC Expert/Scheduler), and it does say to use a NB filter.

    Any ideas?

    Thanks.

    Mark
     
  2. Colin Haig

    Colin Haig Staff Member

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    You could take a look at the logs to see what filter it is being commanded to turn to.
    In MaxIm, View... Log Window.
    Right Click, turn on Time Stamps - they will be shown in UTC time.
    You can also turn on Debug Messages.
    The logs are generally found in somewhere like:
    C:\Users\Mark\Documents\MaxIm DL 6\Log
    and are named like 20200811.log
    Then look at the two ACP logs.
    MaxIm will show you which filter number it turned to.

    ACP normally gets its filter configuration from MaxIm, so if you have them misnumbered/mislabelled, that could be your problem.
     
  3. Mark de Regt

    Mark de Regt Cyanogen Customer

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    Thanks, Colin.

    I examined the log file, and the log says all the right things. But the right things aren't happening.

    For instance, last night I took six 30-minute images of a target; the first two were Ha, the next two were OIII, and the last two were Ha. The log shows the camera selecting the correct filter each time. But:

    1. The first two, Ha images, were fine.
    2. The next two, supposedly OIII images, were clearly broad-band images
    3. The last two, nominally Ha images, were identical to the previous two (OIII) images.

    Later in the night, on a different target, it took four images with the L filter, said it changed to the Ha filter, but just took two more images looking identical to the L-filtered images.
     
    Last edited: Aug 12, 2020
  4. Doug

    Doug Staff Member

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    Sounds like a hardware issue. Most likely candidate is the cable.

    Make sure the I2C cable isn't loose.
     
  5. Mark de Regt

    Mark de Regt Cyanogen Customer

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    Thanks; I have asked the guys at SRO to take a look.
     
  6. Mark de Regt

    Mark de Regt Cyanogen Customer

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    They found nothing loose. But when I tried to image this night, the system would not guide. The AO seemed to be working fine, but the mount was not bumping, and the mount would not guide when I turned off the AO-X and told Maxim the camera was "SBIG Universal."

    Arrggghhh! This can be a frustrating hobby!
     
  7. Doug

    Doug Staff Member

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    What is Control Via set to?
     
  8. Mark de Regt

    Mark de Regt Cyanogen Customer

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    ASCOM direct

    As far as I know, no settings changed.
     
  9. Doug

    Doug Staff Member

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  10. Mark de Regt

    Mark de Regt Cyanogen Customer

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    I'm a moron, and forgot the simple lesson I had learned with my first electronic game many decades ago: Turn it off than then back on.

    I did that today with the camera. It's cloudy at SRO tonight (first time in a LONG time), so I couldn't do much. But, guiding through thin clouds for two 300-second exposures before the roof closed, it seemed to be guiding fine.

    Perhaps that's all that was, and I can get back to solving the "wrong filter" issue (which I think is a failure to change filters after doing the pointing exposure for a new set of exposures in ACP).

    I'll let you know if I have any more problems; thanks for your attention!

    Mark
     
  11. Mark de Regt

    Mark de Regt Cyanogen Customer

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    Now there's a new gremlin with the guider (although, of course, they may be related somehow).

    Some background: For the last several months, my guide star for the AO-X has always been tiny (although almost always mag 7 and binned 3x3), and my errors have generally been in the vicinity of .1 pixel.

    Now, suddenly, the guide star looks like I'm used to it looking from last year, and the way the guide stars on the AO-L with which I imaged for years looked--fairly large, and bouncing around (proportional to the seeing). The errors generally are much higher than .1. But the images are still fine.

    So that raises the first question: What caused the screen view of the guide star to change so radically, and the guide errors to change significantly, while the images don't seem to be affected? And, yes, I have carefully focused the STX guider, twice, and it does not change the results.

    Secondly, the look of the guide star on the screen sometimes changes radically, even to filling up the entire screen (as it did for many minutes last night, perhaps related to clouds coming in). Then it will magically go back to reasonable. I have attached two photos, taken just a couple of minutes apart, during the same subexposure, showing this; the "transition" was the vertical "star" (in the before photo, which had looked that way for a few minutes) spinning around a once or twice (like a slowly-spinning propeller), then looking normal again (as in the after photo). After.jpg Before.jpg
     
    Last edited: Aug 18, 2020
  12. Colin Haig

    Colin Haig Staff Member

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    Mark, without quantitative data, there's not much we can tell you.
    Do you have tracking logs etc.?
    Have you tried running WITHOUT the AO to see if normal guiding is running?
    Is this when you are manually doing this, OR under some other application e.g. ACP control?
     
  13. Mark de Regt

    Mark de Regt Cyanogen Customer

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    I have attached the only log I can find. Can you tell me how to keep a tracking log?

    When the guiding wasn't working at all last week, it wasn't working with or without the AO. But the mount certainly is being bumped now; I have no reason to believe that guiding is a problem. The dominant symptoms are (i) the guide star is much bigger than it had been since I got the camera/STX guider back from the repair in January, regardless of efforts to focus it, and (ii) the star changes shape during guiding, from more-or-less round, to snake-like, to a huge square almost filling up the guide box. Oddly enough, guiding is working (albeit with larger guide errors than before), and my images have very nice FWHM, reflecting the seeing conditions.

    This behavior happens both under ACP's control, and when I'm just manually choosing a guide star and telling the mount to guide.

    As you may recall, I had to send the camera (which was new last year) back in for repair of the STX guider in January. I'm suspecting a loose mirror or something like that from the way the image of the guide star can change so radically. Is there something the guys at SRO can do to check if that's what's happening?

    Thanks.

    Mark
     

    Attached Files:

  14. Colin Haig

    Colin Haig Staff Member

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    Here's the guiding options that are sometimes useful - Record Calibration Images, Record Guiding Images, and Tracking log.
    trackinglog.png
    The tracking log will usually show up in the MaxIm DL folder under Documents.
    AO operation is different.

    I'm going to ask @Bill to comment on the STX Guider - he might want to contact you off line.

    I really think something else is going on here.

    Have you done a basic Move test?
    Guide tab, Move, Manual move of say 3 seconds in each of +y, -y (Dec), -x, -y (RA) to see that the DEC coords change, and RA slows or speeds up.
    That way we can eliminate it.
    The second image in your post #11 above looks like the mount or AO was in motion and smeared the star.
    That's what I don't understand. It should be still, like the first image.

    @Doug or @Adam Robichaud - any comments?
     
  15. Mark de Regt

    Mark de Regt Cyanogen Customer

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    Thanks, Colin; I look forward to hearing from Bill.

    Yes, I have done a move test, and the mount is moving an appropriate amount.

    Yeah, I know that the image with the vertical star looks smeared, but that's just the way it looked for many minutes. Then, as I watched, the vertical star started rotating, then, after a few seconds of rotating, appeared as a more-or-less round star again. Oddly enough, it was guiding ok the whole time, judging from results (the previous night, when the star was a huge square, it wasn't guiding so well, but that may have been the clouds causing that). And, earlier last evening, the star was a horizontal line.

    The seeing was poor (well, poor for SRO, at around 2.0 arcseconds) during the time when the star was vertical, but the 15-minute image taken while the star was vertical still had a FWHM of 2.0 arcseconds. I really believe that the mount is playing nice with the software, and the guiding is fine
     
  16. Colin Haig

    Colin Haig Staff Member

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    Yep, thin clouds at SRO a couple nights ago, so a lot of wasted imaging time... darn clouds. :rolleyes:
    Ok, so glad you have had a successful move test.

    Regarding the square / weird star image that appeared periodically, this is something SRO guys could check.
    There are a few AO-X units out there that we've seen stray light from the Red LED on the side making its way into the optical path.
    Usually the symptom is an oval or reflection on the main camera images. I've seen an instance of guider images going up/down in background brightness.
    This is due to a lack of black anodizing on the inside frame and a light leak from the black LED holder.
    The resolution is either a bit of black foam (like weatherstrip), flat black paint, or the easiest solution is black vinyl electrical tape.
    See attached photo.
    aox_tape.jpg
    This is a photo from a customer. I added the yellow arrow showing the LED. You can see that since it doesnt totally poke through the hole in the red frame of the AO-X that light could reflect internally.
    I don't know that this is the problem with the guide star filling up the guide box, but it's worth a shot. The downside is the camera has to be removed from the scope, and this has to be checked.
     
  17. Mark de Regt

    Mark de Regt Cyanogen Customer

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    Thanks; I'll pass this on to the guys at SRO.
     
  18. Colin Haig

    Colin Haig Staff Member

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    If it turns out yours has this issue, please let me know the Serial Number of the AO-X. (Send a PM if you wish).
     
  19. Mark de Regt

    Mark de Regt Cyanogen Customer

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  20. Mark de Regt

    Mark de Regt Cyanogen Customer

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    Colin, they did the surgery you suggested two nights ago, and last night was clear enough of smoke to at least pretend to image. The guide star still is much larger than it had been before last week, but the guiding seems fine, with FWHM of my stars on 15-minute exposures through the luminance filter matching the seeing shown on the seeing monitors. So, while I'm mystified by the larger guide star (and larger reported RMS guide errors), it doesn't seem to be affecting the quality of my photos (although I reserve judgment on that until we have a night of good seeing), so I'm not too unhappy about that. And, to be clear, the guide star looks and acts pretty much as the AO guide stars have always looked and acted for me since I started using an AO-7 in 2002, other than the last several months after I got the STX Guider back from Bill with a replaced missing lens.

    If I wanted to trouble-shoot my suspicions that the system still is reporting a filter other than the luminance filter when it actually is imaging through the luminance filter, would swapping in a new cable between the camera and the computer be a good place to start?

    Thanks.

    Mark
     

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