Well, hello again. not new photographer , but new photographer HERE

um im not a beginner and not proffesional either, so i bought last week my new camera,
the Canon SX10. till now im getting really great results and im very pleased with her.
about two days ago i shot the moon and it went well, so i wanted to take another step -
and try to take picutre the stars. well i searched a lot for tutorials and tips but i couldnt find any that will match my camera, all of them were for DSLR's with 30 secs of expusre; my min is 15 secs. any help here guys?
also another question, ive encounterd with 100+ secs of expusre shots. there are cameras out there that can do that? or is it a bunch of photos - max 30 secs [or so] - composed in photoshop?
really looking forward your answer

thanks