Prime focus with a 8" dobsonian

[Pincs]

Hi, I just got a canon eos 600d to take pictures with my skywatcher 200p scope. I am using prime focus with it which seems to work fine despite the problems people face with getting it to focus. I plan to get some great shots of the moon, planets and orion nebula but I was wondering if theres a way I can get shots of dimmer objects in the sky. At the moment i am finding this hard as I am limited to a 1.5 second shutter speed in order to prevent star trails, I am putting the ISO up high to get the most light but I was wondering if there were better ways to go about getting the best pictures without a tracking mount. Thanks.