Issue with 1x1 binning for dark frames

Discussion in 'STX and STXL Series Cameras' started by Peter Brack, Jan 24, 2018.

  1. Peter Brack

    Peter Brack Cyanogen Customer

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    I am currently doing a run of dark frames via the Web Interface of ACP

    There is a difference in the 1x1 dark frames and the 2x2 dark frame.

    The 1x1 dark frames are all white, and the 2x2 I think are essentially normal.

    The only other difference I have noticed is that the compressed file sizes are different.

    The 1x1 binning files sizes in zip form are around 67KB, whereas the 2x2 binning zip are around 4.5 MB- that seemed ounterintuitive.

    When expanded the 1x1 images are around 32MB and the 2x2 are about 8MB- I would assume that is normal

    Have included a screen shot from pixinsight- they have both had screen strctch to them with ScreenTransfer Function.
    I thought when the images were taken that in Maxim DL the image was black not white.

    This is the same if the images are 120sec, 300sec, or 600sec
    I am assuming that the SBIG keeps the shutter closed when taking flats. Am also taking them at night.

    Peter
     
  2. Peter Brack

    Peter Brack Cyanogen Customer

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    Forgot the photo...
     

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  3. Peter Brack

    Peter Brack Cyanogen Customer

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    I should add, that the non-compressed Maxim DL file around 32 MB that is originally downloaded is also all white for the 1x1 binning
     
  4. Doug

    Doug Staff Member

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    Not for flats... definitely does for darks. Are you taking the right frame type?
     
  5. Peter Brack

    Peter Brack Cyanogen Customer

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    Apologies Doug, I meant darks- was 3am here! I am taking them through ACP Web interface and selecting the Calibration Frames. So it says taking "Darks". Sounds stronge that it is one the 1x1 that are all whited out
     
  6. Peter Brack

    Peter Brack Cyanogen Customer

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    Doug, here is a screen shot from Maxim DL for Bias 1x1 and Bias 2x2 taken via ACP Web Interface for Calibtration frames.

    Again, you can see the 1x1 is all white, and the 2x2 is what you would expect ( I think )
     

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  7. Peter Brack

    Peter Brack Cyanogen Customer

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    I took some light readings of two dark frames I just took, one of 1x1, the other 2x2, for 60 seconds. The 1x1 again looks all white and has a uniform reading of exactly 65535 ADU everywhere. The 2x2 binned image's reading are around 49280 ADU but varies small amounts everywhere.

    Other dark i have on record previously have readings around 1100.

    I don't know what to make of these images. It can't be light leakage as a 60s 1x1 looks white whereas a 900s 2x2 has a lower reading.
     
  8. Tim

    Tim Staff Member

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    Can you send us a copy of the white FITS image to examine?
     
  9. Peter Brack

    Peter Brack Cyanogen Customer

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    Hi Tim

    Have included a fits, a 60s one , which is the same as a longer one

    peter
     

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  10. Peter Brack

    Peter Brack Cyanogen Customer

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    this is a 60s dark 2x2 fits for comparison
     

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  11. Peter Brack

    Peter Brack Cyanogen Customer

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    This image I took with the guiding chip and shows a normal dark frame, which would mean there is some issue with the main camera.

    I tested this directly through MaximDL. I have off axis guider and have dual chip selected, and sbig universal.

    Latest Maxim DL 6.16
     

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  12. Peter Brack

    Peter Brack Cyanogen Customer

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    I have not only tested through ACP , but direct through Maxim DL and TheSkyX Camera Add on . They all reproduce the same thing. The guider chip seem to be working okay. The main sensor is where I am getting the problem.

    I don't understand what it means- is it damaged? It shouldnt be producing such high ADU readings. It is also dark there and not in the middle of the day, so if the camera shutter hadn't closed properly that might be an explanation.

    Any ideas?

    I cant test on light frames at present as have some COMs problems connecting to the telescope to over the dust cover...
     
  13. Tim

    Tim Staff Member

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    Can you confirm the camera is in a dark location? Is the problem only with dark frames? Do light frames look ok?

    Can you provide the serial number written on the camera?
     
  14. Peter Brack

    Peter Brack Cyanogen Customer

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    It is in a dark location. You can tell that the auto guider chip is producing dark frames normally, if you see the last fits i posted is coming from that

    i cant test the light frames at present as mentioned in previous post

    i cant provide serial number as I am not physically there. It was purchased new in 2016
     
  15. Peter Brack

    Peter Brack Cyanogen Customer

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    Doug, do you have any ideas whey the main camera is producing these images, while the off axis guider is producing a normal dark frame.

    Could it be down to a faulty usb hub or could it be something wrong with the camera
    What would make the images so overexposed, in a dark environment and where the auto guider darks look normal

    Peter
     
  16. Peter Brack

    Peter Brack Cyanogen Customer

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    Today I was able to take the SBIG camera USB cable out of the USB Hub and connect it directly to the computer.

    This corrected the image problems I have mentioned in this thread. I don't know why it suddenly started happening, as have had the same set up the past 9 months. Anyway I am happy it is working and that the STX has a happier home plugged directly into the computer, something I should've done from the start.

    Peter
     

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