What does this mean?


New member
Sep 5, 2016
I am using the WBPP script. I am using master darks and a super bias that I made prior to image acquisition. I am not actually using WBPP to do final integration (although I would love to see the rough integration in WBPP, and check the box to do it), but I am applying cosmetic correction and generating drizzle data.

I add the following files:

Superbias (XISF)
Master dark (XISF)
25 flats per filter (FITS)
Light frames (FITS)

On diagnostics or running the script I get this:

** Warning: Flat frames (filter = Lum, binning = 1, exposure = 2.25s, length = 25) will be calibrated with a master dark with a different exposure of 300 sec.

I'm not sure what to take from this. Shouldn't my flats always be different exposure lengths (2-5 seconds for mine) than the master darks (5, 10, 15 minute)?

I get one such error message per filter, and no other warnings on diagnostics or running.

WBPP completes its work, but then fails to do an integration. I can get by without it since I drizzle integrate later, but I've found that PI is always a lot smarter than I am, and I suspect I am not using the script correctly somehow. What am I doing wrong?


PTeam Member
Feb 1, 2014
I would highly recommend you check out my WBPP series.

You do not have the "Use Flat Darks" checked which means WBPP will pick the closest exposure time it can find which is your 300sec dark.
It is likely you want WBPP to use your Bias to subtract from your flats to calibrate them. You then need to check "Use Flat Darks" ..and because it will not find any darks- it will tell you it is using your bias. There is another part of this which is the checkbox concerning Optimization. I would reccommend first getting things to work without this, and then investigate it if your sensor and calibration data allow for its use.
One more thing..and all of this is explained in my videos, some sensors (CMOS) do not have well behaved biases which forces the acquisition of matching flat darks for your flats.

If you like my answer or the video I posted, please do write back about your experience.
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