SteveinNZ mentioned loading CHDK onto your camera's memory card.
When I first started out imaging, I only had a bridge camera as well, a Canon S3IS. I loaded CHDK onto the SD card and it was amazing.
One of the many functions it adds to your camera is the ability to do long exposures. Up to a minute long last time I used it. They may have been able to extend that time.
This means you can take multiple images, with your camera on a tripod, and stack them in Startrails.de and make time lapses and star trails. You can do that already with 15 second exposures, but 1 minute is even better.
http://chdk.wikia.com/wiki/CHDK