During 5 hours there is a lot of luminosity change in the end due to this my pictures have more and more noise to them.
What time did you start, and what time did you end?
I guess it ends pretty late at night....
Quite nice video, and the motion of clouds in two different directions is great
I would say 20 secs. is too long as an interval , as the clouds' motion is no longer fluid, but I know that with batteries, you can't get more than that... if you shoot more frequently you won't have 5 hours of life !
When you'll get the power adaptor it will help in that. I was thinking about one too, but then I'd constrained by AC availability, and I think being free to select locations is a must for nice timelapses.