This was shot over two nights, and I didn't get the rotation right the second night. DSS got all soggy and hard to light trying to register the 78 subs, leaving some weird blurriness and some odd bright arcs. Siril did the stacking and stretching OK, but left me with an essentially monochrome image. So I did the old smart-object stack-mode-median dance in Photoshop, and stretched and fiddled from there. 72 x 180", ISO 800, gear in signature.
Let the beatings begin! I really do seek suggestions here. For one thing, I should shrink stars, and the whole thing looks somehow soft to me. What else?