Another useful feature of this and many other good Internet forums is once you have started a topic, the boards often list suggested reading of similar topics already created down at the bottom of the page. I am certainly not discouraging anyone from creating a new topic and sometime using the topic search feature will make your head spin but it is just another great service of this message board that similar subject matter is listed near the bottom of the page of every topic posted on the forum.
By now I am sure you are filled with great suggestions and very anxious for clear, dark skies and several minutes to yourself tonight so you can go out there and get better results.
Your images do seem very soft on focus. Sometimes the position of the tripod and your body restricts how well you can see in the viewfinder without bumping the camera even to focus well. I keep my tripod as low to the ground as I can to reduce vibrations of extended legs, mounting pole and such. Rarely do I fully extend my tripod; I sit or crouch beneath my camera to focus and operate the remote to take the shots.
Here is a recent shot taken with my K10 Five Star 500mm, t-mount lens coupled with two - 2x teleconverters: a Focal MC 2x and a Star-D MC 2x.

This should be iso 400 at 1/30th with the lens set to f11 but remember there are two tc at work here.
The software used in your crop, your jpeg settings and focus may be your enemy.
Also for the record, I often break some of the suggestions. Lately I have been setting up shop in my driveway, shooting the moon when it hits it's highest point in the sky which was less than five hours after sunset and just about in the center of a city with a population of more than 60,000.
This one was taken with the Five Star 500mm and Star-D tc using the K-7 in the early morning, shooting from my backyard focusing over the neighbor's house.

Now these are far from the sharper images other have demonstrated around the forum and I realize there are steps I can take to get sharper also. You should get there very soon as well.