Thanks Jeff for the explanation. That was almost 14 minutes of shooting. Hope you had a grip with two batteries.
I found a cheap intervelometer worked very well on a900. You can program it for how exposures, how long each exposure and how much interval between exposures. Put the camera in BULB mode and let it go. I think I paid about $30 for it. I found for another $10 I can buy a set of connectors for different cameras.
So even if you change brand you are convered.
I am almost tempted to by a light trigger but have not pull the trigger yet.