Now back to the practical side, i have many objects imaged with the Canon 6Da in my archive and want to combine those RGB’s with new Luminance data. So i have years of iso1600 RGB data with corresponding iso200 flat frames. But there is no way that i can (re)stack this data with APP because the flat calibration is not done for these datasets. So i have to do the (re)stacking in Pixinsight if there is no “override” option for this.