stacking with internal camera dark reduction feature?
Stacking program, astrometric (plate) solver, fits file viewer
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Hi,
I am using the internal camera dark reduction feature so separate darks are not available. It appears to me that stacking images is not possible without separate darks as I am getting an 'access violation' with the warning that suitable darks could not be found (and the program usually crashes or freezes).
So my question: are separate dark frames mandatory?
Are flats and flat darks also mandatory?
Thanks in advance and cs
Axel
You can stack without darks, flats and flat darks. That should always work.
I suspect the light is causing problems. Share two images so I can have a look here in the debugger.
Han
Sorry, not sure how to share images - using the insert image button?
E.g. upload them to the site below and send me the link:
https://ufile.io/
Han,
here we are: https://ufile.io/sfl1q67x Image are 30s images from a D5100 with internal dark reduction activated. I have also added two flats.
Please also find attached a screenshot of the resulting astap error message.
Axel
The conversion to FITS does not work because I assume DCRAW is selected. Switch to Libraw conversion. See attached screenshot.
I will fix it for DCRAW or give a proper error message in next ASTAP version.
Han
I found the cause of the error and fixed it in the code. Does the Libraw conversion work? If not I will release a new development version of ASTAP to fix the conversion by Dcraw.
Han
Han,
thanks, the Libraw conversion works. However, when adding some flats I receive another error message commenting on the lack of darks (attached).
Axel
The missing flat-dark should not give an access violation error.( Having them is better) Are you sure your still on mode Libraw?
This warning "missing..." message you can ignore. The only problem is that maybe the corners will be over corrected and brighter then the middle of the image.
Han
I am right now not at my pc that runs astap but I am rather sure the setting was still Libraw. I will check that.
The problem with the error message is mostly that after closing the message box astap will either freeze or close completely.
Just checked - setting is Libraw (see attachment).
I am still running 2023.08.23 (64 bit) so not the newest version. Might this be an issue?
I noticed that with any setting the "Test pattern" button is always inactive.
The attachment seems to have been removed by a spam bot protection.
Just updated astap to 2024.01.12 to make sure I have the latest version installed. The error message pointing to the darks remains the same:
Warning, could not find a suitable dark for 30 sec, temperature 999°, gain 800 and width 4948! De-classify temperature or exposure time or add correct darks. See report in column ISSUES in tab dark.
The issues column in the dark tab is empty which is understandable as no darks have been loaded. 30s exposure time and gain (ISO) 800 is correct but as the camera is a Nikon no temperature data is available. Might this be a problem?
That is not a problem. Ideally you should have one or more darks taken at about same temperature plus minus a few degrees Celsius as the light. It will take a lot of the hot pixels away.
If there are no dark, just ignore the message and just continue with stacking.
Han
Thanks, I will check on that.
Perhaps it would be ok to change the warning message somewhat: it sounds very much as if something would not work properly.
What does "De-classify temperature or exposure time " mean?
This field is empty: "See report in column ISSUES in tab dark" so there should be some information if the warning has to have a meaning
cs Axel
De-classify means you uncheck the "classify check marks". You could in the tab dark load/keep several frames of different exposure, temperature ( A library). If the check mark exposure time is checked it will search for the dark with the same exposure time as the light. Same for temperature of the dark and filter used for the flat. Most people like to get most out of there setup and image and could use this to get good pairs.
The issue message will report a different temperature in the column issues. That will not happen in your case, but I will have a look.
Han
Han,
thanks for your explanations. You are doing a great job!
cs Axel