Indeed and stacked versions don't allow you to kip anyway, you need to keep pressing the remote [or be clever setting up continuous timelapse maybe] I know this is film, but to show how same applies across either medium, first link is a stacked images, about an hours worth of 30sec exposures, over the M25 [so ooooooodles of pollution that even an grad filter would have struggled to control on a single exposure] and the stacking software takes the important info from each frame and removes the unnecessary data, so the result is something that looks like a single frame, without of the light intrusion problems.
https://www.flickr.com/photos/wgi/11897842143/in/datetaken/
This is single 30 min exposure down at dungeness, heavily pp'd to remove the worse of the noise but it is still very apparent even in this small version imo.
https://www.flickr.com/photos/wgi/2...QeD-5bu8uf-5bu8qj-5bpPNK-5bu82h-5bpPCp-5bu7Qb
I now want to go somewhere very dark and do a star trail on film... soon...definitely soon