Yesterday I shooted M92 cluster because no other object was well in sight. Until 0:30h CET. M27 came in perfect position so I decided to stop M92 shooting, and I switched to M27 at the same settings (400mm, f/5.6, ISO1600, 120s). This way I was able to use the darks and bias frames (taken after M27 lights) for M92 and M27.
On 03:00am all images was taken. It was a short night for me… 😉