[Sticky] Warning - Light Leakage, Bad Sensor Offset, Underexposure

Posted by: @seanhagerty

I have been getting a dark frame error since I updated to v1.083.  Says something about light leaks or a settings mismatch.  Anyone else getting this issue?  

 

I shoot my darks in a dark room , and even then I cover the telescope with a dark blanket to stop any stray light from leaking in.  I also use the same settings for my shots.  

 

Anyone have any thoughts on this?

 

Sean

Hi Sean,

Thank you for sharing.

You are given a warning. It is not an error,...but the warning should be taken seriously. The warning is new in APP 1.083, this is from the release notes:

FIXED & OPTIMIZED, 2)CALIBRATE, the implementation of the adaptive pedestal is now faster and the calibration engine has a new warning system against data that has issues with sensor offset, ligh leakage, incompatible calibration data.

This is the warning that you get right?

Something similar like below will be shown in the Console window when the warning is triggered.

So you need to double check all 3 that can cause your data issue:

1) Possible Light leakage (you say it can't be the problem, because darks are shot in dark room, I say, please verify by looking at the darks because I know a dark room is not perfectly dark in my experience..)

2) Wrong sensor offset of darks/bias when compared to sensor offset of the lights. The sensor offset is  usually an option that you can set in your capture software. Different software and even different versions of the same software can create this problem big time ! by having changed or using different camera control.

3) You simply have underexposed your lights, so when the darks and/or bias are subtracted, many pixels are clipping to 0, even with a very high artificial/adaptive pedestal that APP is applying on your data.

So please verify yourself which is the problem, if you need help by us looking at the data, that is perfectly okay 😉 Then upload the data on which the warning is triggered here:

https://upload.astropixelprocessor.com/

username and password: upload

Please make a folder with your name and description of your issue and let me know once uploaded 😉

Mabula

@mabula-admin

Thank you for taking the time to look at my issue.  I will definitely post my data.

Sean

Dear Sean,

Thanks, I will look at your data now and will report back when finished.

Mabula

@seanhagerty I was also getting this same error with APP, but redoing all my calibration frames with the latest version of Nina has defiantly sorted out this issue for me, I think that in my case the latest version of Nina has been updated with the latest SDK drivers for my ZWO camera, so that I am now shooting all my lights/darks/flats/darkflats with the same driver/settings.

Posted by: @gary-clayton

@seanhagerty I was also getting this same error with APP, but redoing all my calibration frames with the latest version of Nina has defiantly sorted out this issue for me, I think that in my case the latest version of Nina has been updated with the latest SDK drivers for my ZWO camera, so that I am now shooting all my lights/darks/flats/darkflats with the same driver/settings.

Dear Gary @gary-clayton, thank you for your feedback.

It maybe is semantics, but it is a warning and not an error. We try to warn you that your data has in fact an issue 😉 and that you will be best served if you solve it and thus you will get better results with your images !

As a rule of thumb : never try to shoot lights and calibration data with different versions of the same software, let alone use different software packages.. if something in the capture software is updated in terms of camera control, it will be problematic.

Mabula

Posted by: @seanhagerty

I have been getting a dark frame error since I updated to v1.083.  Says something about light leaks or a settings mismatch.  Anyone else getting this issue?  

 

I shoot my darks in a dark room , and even then I cover the telescope with a dark blanket to stop any stray light from leaking in.  I also use the same settings for my shots.  

 

Anyone have any thoughts on this?

 

Sean

Edit by Mabula: promoted to Sticky since this warning is new in APP 1.083 and is there for good reason.

Sean @seanhagerty,

I have processed all your data in the 1.083 stable release with default settings without any problems. So maybe you change some settings in 2)Calibrate?

Like making 16bits masters or enabling dark scaling?

Mabula

Hi Sean @seanhagerty,

Today 2022-01-11, the 1.083 installers were updated with a small adjustment for this warning system we implemented. It will now only trigger in less severe cases. Simply uninstall APP, delete the downloaded installer and then download and install APP 1.083 again. Your dataset should not trigger the warning again 😉

Mabula

I’ve been getting this error even though the resulting image sure looks good.  I suspect that my lights may be a hair underexposed since I still need to add autoguiding to my rig and can only expose for 60 secs or less right now on an 8” scope.  

Here’s something interesting though.  On my last session I took just 54 60 sec subs.  When I integrate them all, I get the error (403 pixels clipped).  However if I include fewer than 41 subs, I don’t get the error.  Why would this be?  I’m using APP 2.0 beta 3 on a MacBook Air.

Thanks,

Jason

@pdxscullys Hi Jason,

Only 403 clipped pixels indeed indicate that the lights are slightly underexposed. Hopefully autoguiding will allow you to go up to 90 or 120 sec, which may already take care of that.

It is hard to say why including fewer subs would make the clipping pixels go away. Were the 13 subs, that were left out, taken at the start or the end of the imaging session? If yes, could it be that those subs were taken with the object too low in the sky to get a decent SNR? Or perhaps those are suffering from wind or bad seeing or other causes that makes the SNR go down?

Wouter

Hi Wouter,

The remaining frames were taken at the end, but if I do an integration with just those 13, I don’t get the warning either.  When I get a chance, I’ll integrate the last 41, rather than the first 41 subs to see if I still get the warning.  

Hopefully more of a curiosity than an issue once I add the autoguiding gear and can get more signal/sub to address what’s likely the core issue 😀 APP is truly an amazing piece of software.  I only started this hobby/obsession this year and APP enabled me to produce some very satisfying results without the time investment required by some of the other popular packages out there.  It just works!

Clear Skies!

J

It's also not a big problem if it's just 403 pixels, just a warning in that case to maybe tackle that, but it shouldn't be a huge issue I think.

@pdxscullys Adding to what Vincent wrote, how did you discover that leaving out those 13 frames solves the issue? Can you leave out only one or a few, for instance only frame #42 or frames #42 to #45 and still integrate properly? That may indicate an issue with only one or a few frames.

@vincent-mod Yeah, totally agree.  I do wish it wouldn't hold up the processing though and just fire the warning so that I don't have to tend to it when processing a couple hundred subs.  I did pull the trigger on an OAG and guide camera though!

@wvreeven I integrated a handful of subs just to make sure it didn't throw the warning and hold up the processing.  After that succeeded, I selected all the subs for integrating and then went surfing. When I came back, the warning screen was displayed.  From that point I tried 25, 35 then 45 subs.  45 threw the warning, but 41 didn't! I didn't try what you're suggesting though.  Being curious, I just tried the 41 "good" subs and the last one--no warning!  So it does look like one or more of the last 13 frames is the culprit.  However, if that's the case, then I wonder why I could successfully integrate just those 13 frames without throwing the warning? 

@pdxscullys Yes, I made a note of that to have a look at a way to not stop processes in case of non critical errors. Maybe just have the popup without stopping or something like that.

Good day I have the same problem. The peculiar thing is that he tells me that 9M pixels will go to zero.

I use the same Darks and Bias that I did a few months ago for NGC 7635. If I process that dataset, I don't get any warnings. If I use the same Dark / Bias for new photos I get the warning.