I know that in order to make a correcte FLAT frame we need to pay attention to the histogram.
I'm using a cooled CMOS camera (no reflex)
In addition to use the same temperature and same gain, we need to play with time exposure in order to put the histogramat the center or little shifted to left....
If this is all correct, I'm not able to see the histogram in a fixed scale on viewer fits of kstars. I can zoom and zooming in or out the scale change so I'm confusing.....
There is no a way to have a fixed scale?
If not, how can I manage the histogram in order to see the correct xposure?
I hope to have been clear