[raymo]

I don't have a lot of info to work with, but your problem shouldn't be too
hard to pin down. Firstly, Saturn at prime focus [ camera coupled to scope directly with no eyepiece] would be very very small in a short focal length scope like yours, and therefore hard to find in the camera's viewfinder.I don't think the D3000 has live view to help you.
Regarding the moon; this might uncover the problem. If you can only
get an image that is way out of focus, it is possible that your scope will
not come to prime focus with your camera as it is presently mounted.
Many Newtonians have this problem. Some can be made to work by
using shorter couplings between the camera and the focuser, and others have to have the primary mirror moved up the tube a bit.
In daylight mount the camera and try to focus on something at least
500metres away. If it won't focus, remove the T-ring and any other
adaptor, and move closer to the open end of the focuser while looking through the viewfinder. If it then comes to focus, or is obviously
getting nearer to it, you have found the problem. Then you can look at ways of fixing it.
raymo
P.S. when looking through the viewfinder at the open end of the focuser make sure the focuser is racked all the way in.
Regarding the focus on the D3000 being not great when no lens is fitted. You cannot focus with the camera without a lens; you have to use the scope's focuser to focus the image.