1. The sky color changes dramatically as clouds move in and out of the frame. And long exposure shots of moving clouds look crummy, because it's just a blur!
2. Two minute 15 second exposure (along with the other camera settings) was too short. I had to increase the exposure in Photoshop. Next time, I may try a 5 minute exposure.
3. Be careful about leaving your camera outside all night long. I had a panic attack this morning until I saw my camera was still in the back yard right where I left it!
4. You can use Picasa or similar software to put your series of photos into a movie format. I've never tried this before, but it's pretty easy and I like the way it turned out. Click on this link to check it out. Kind of a time-lapse photography effect.