Resolved ST402 - Strange Image After Dark Frame Application

Hello! I'm getting strange results in all three filters after applying my master dark frame to images. It seems inconsistent as well. For the last several nights, I've spent several hours collecting images of the short duration variable RR CET. B, V, and I filtered images take about 5 minutes to get, and the loop continues till the variable is under 30 degrees. I use an older SBIG ST402 camera at 1x1 binning and -10C cooling. No stacking, just a straight time series
I've attached two raw adjacent images and the processed images (dark at 120 sec and -10C and the flat frame. The strange result does not occur if I only use the flat, and does occur if I only use the dark frame. I've redone the dark without effect. I've used darks and images from NINA and SGPro, I get the same result when calibrating using MPO Canopus and AIP4WIN. Has the offset changed? FITS header?
I tried updating the firmware, but for some reason, DriveChecker says that cannot be done.
I don't know if this is something within the camera or a strange result with the calibration programs. I don't know what to do next. Thank you four your help. Mike

 

Thanks! I included the two raw frames along with the processed frames (both dark and flat applied) in the previous post. The processed images both end in 'P' in the titles.
I think it might be a gain and offset issue. I can specify e-/ADU in SGPro as 1.5. The fits header for the images acquired through NINA list egain and offset as both zero. Also, the images has pixels darker than the master dark, so that would result in negative numbers? I'm hoping to get into NINA to check these, but the menu is grayed out at this point.
Anyway, it seems more the software issue than camera/EPROM issue. However, I would appreciate your take on the attached raw and processed mages. Best regards. Mike

 

Thanks! The fits header says egain - 0 and offset = 0. I've asked for additional guidance on the NINA discord site.
In any case, this does not look like a camera issue, which was why I asked for guidance if that were possible on the SBIG forum.
Thanks again! Mike

 

Thank you again. I think the problem is that I changed how I obtained my darks, which resulted in higher pixel values that were greater than the lowest image pixel values.

I am curious though. Is there a way to check the offset/pedestal that a program reads from the camera? NINA cannot read it, so the tab to check offset is grayed out. As a result, in the fits header, egain and offset are listed as zero, but I think this is because inability to read the values rather than what they actually are.

However, the most likely thing is my workflow. I think I had a low level light leak when I made the darks. I've been wrapping my brain around possible software issues, but nothing has panned out. When I had the camera in my position, I covered the camera well to make darks even tough the ST402 is supposed to make darks without additional work. At Starfront observatories, the camera was on the scope uncovered without the front cap. So, I'm redoing my darks paying articular attention to eliminating light leaks as much as possible. The first experimental raw dark still showed a few pixel values above the lowest pixel values in the image I took last week, though much better. I'll finish the new master darks and do a new run so that I can check completely. Thanks again for your help


Mike

 

Hello! I had thought that there was a problem with my master darks, that there was a low level light leak that raised the darkest pixel above the darkest pixel of an image. However, after taking great care with a new set of darks, it has happened again.

I have attached one of the raw files that had a problem. Do you see the possible wrap problem you noted before?

You suggested imaging with different software to see if there is a software cause of a wrap problem. I'll try the driver SBIGUDrv.dll 4.9.9.8 with SGPro. The most recent version would not allow connection. There is a community driver called HomeMade.SBIGDrv.dll that I'll use in NINA after renaming it SBIGUDrv.dll in that directory.

I was going to try CCDOps, but it won't start now despite installing and reinstalling, so I need to figure that out. If you have guidance
about "CCDOps - Application Error. The application is unable to start correctly (0xo00000007b)" I would appreciate it.

Thank you. I appreciate your guidance. Best regards.

Mike

 

Thanks! Lots of telescopes at Starfront.

Mike

 

Hello! I've done everything I can think of (and various forum recommendations!) to identify and correct this problem. The next step would be to evaluate the internal electronics for cleaning, servicing, and possible repair. Is there someone at SBIG who services Legacy models? Thank you and best regards.
Mike

 

Thank you for your guidance. I appreciate it. Best regards.
Mike

 

Success! The run last night with the new power supply to the SBIG ST402 looked much better. No noisy images that had to be discarded. I'll test for a few more nights, but looks like the new power supply for the ST402 took care of the problem. The wrapped images were the result of the processing software that wrapped negative pixel values. Best regards. Mike