With my RASA8 Iv'e shot 184 light subs of a galaxy field under the new moon, with som pretty heavy gradients caused by the moon.
My normal flats wont work for this as it only takes care of vignetting. So I made a synthetic master flat from the stacked lights in Pixinsight, a master flat that to me looks very promising. (I first tried to make a synthetic flat in APP, but due to the limited gradient options it didn't turn out good) This PI master flat was then saved as a 32 bit float fits.
The problem is, and I've tried everthing solution I possibly can find on this, but no matter what I do, APP does not calibrate the lights with this master flat. The results look identical with and without this master flat loaded.
I am able to fix the gradients with the Light Polution Tool, but I would reaaly like to get the synthetic master flat thing working as I see a lot of potential in this for different reasons.
I've attached a light sub and the master flat I made in PI.
Calibration frames made in other software, won't work very well (if at all) in APP as the way other software produces that data, differs. It's always best to use the same software for both data and calibration data so you know both are treated in the same way. In your specific case, your regular flats should work fine, taking out the vignetting indeed. What remains is light pollution is this is exactly where the LP tool is made for. A flat or synthetic flat won't take care of that very much.
