A poor man's method I just came up with that seems close enough to me would be to put your camera on the 30 second long shutter speed, and set your timer to the 10 second timer with 10 exposures. That way it would take 5 minutes of photos at a time, and you would just have to press the shutter button after that. Sure that'll still be quite a few presses over the course of an hour or more... but not as many as it would have been!
It seems to me leaving the shutter open for 30 seconds with the aperture wide open (per instructions HERE) would give you an over exposed photo. Perhaps I am misunderstanding something here. Also before taking the photo with the timer set to 10 exposers it counts down 10 seconds at the very beginning of each set but between each of the 10 photos is only about 1 second, so every set would not be equal.
I see in the instruction manual (page 53) it says: "the interval between the multiple shots may be prolonged depending on the image-recording quality and flash" but it does not say how to change the interval length. It would be nice if I could get the camera to wait say 10 seconds or maybe 30 seconds between shots.
Thank you for your help!