I notice that a lot of my pictures have issues with blending in sky. Since there is no detail there is nothing to place keypoints on.
The only way to handle this fluently is using a head which writes xml files for positioning those featureless images. Thanks to AlexandreÂ´s help even i understood the procedere to use it adaequatly in the meantime . . .
Years ago i found a workaround for shooting indoors with white walls: i sticked small dots onto the walls - that helped a lot! Now i use the headÂ´s xml for those cases also.
If you use a very precise manual head and always fixed camera/lens mount you also can make a template - which assumes images always to be in the exact same position. For featureless sky-images that works very well.