One thing I read is that for smooth motion you should aim to have a shutter speed of half the time between frames. So, if you're shooting at 24 frames per second you use 1/48th (1/50th is close enough) shutter, and if you're shooting 1 frame per minute, you use a 30 second shutter speed. It results in nice motion blur without things looking too smeared.
Obviously 720 exposures of 30 seconds (for 12 hours of real time) is gonna be pretty hard on the camera battery.
EDITED: 11 Jun 2012 11:42 by CAER