Hi all,
Encouraged by my initial tests, I decided to decrease the length of Lum subs from 5 minutes to 3 minutes only. On average, Lum subs are sky-limited in about 2 minutes in my location with my rig, but when it occasionally gets darker longer subs might be beneficial, so I decided to stick with 3 minutes.
Last night I was able to collect nearly 3 hours of 3-minute Lum subs and the data seem to be better than with 5-minute subs.
I selected the best (darkest) sub and used it as a reference for making stacks with various number of subs. Removing 10 brightest subs did not make things better and it looks like unless a sub is really bad (read: with bright background), it is better to include all in a stack with significant number of subs.
Perhaps bringing background noise down to st.dev. = 10 ADUs can be done in just 10 hours with 3-minute sky-limited subs, as opposed to 40 hours with 5-minute subs with my rig in my location.
A link to a stack of 55 3-minute Lum subs:
http://cdn.astrobin.com/images/thumb..._watermark.jpg
Suavi