One reason for the short times is simple. "tracking error"
At 30s you can get by with just about anything with a motor.
At 1 hour you need a very very expensive mount and drive and
guider CCD and guide scope.. All of which will come to about $10,000.
That seems like a lot of up-front expense for a $300 camera.
You may as well pitch in another $6000-8000 and get a better/bigger CCD
camera and another $1500 for the software to process the images.
Oh, I forgot about the $5000-15000 for the telescope.

Well, you can get by with a lot less, but not for 1 hour exposures.

Steve

So it does do 1 hour exposures ?