Nine hours of hydrogen-alpha on NGC 2070 through Sombra, in 600-second subs. Guiding held at about 0.6 arcseconds RMS all night, which is the mount behaving.
The flats were taken against the dawn sky rather than the panel, and the gradient in them was strong enough to leave a visible ramp across the stack. Retaken the following evening against the panel and the ramp went. Worth logging because two of the three guests had never seen what a bad flat does to a good stack, and it is a more useful lesson than a clean result would have been.
Logged by Bo Lindqvist, imaging lead.