Hi Stuart
Well done on a great first image, nice and sharp. Perhaps you could've cropped it a bit and maybe reduced the exposure a tad? But very well done.
I started with a 10" dob too, and taking photos through the eyepiece is the perfect way to see if you like astrophotography.
Later on, you'll want to put your 10" on an EQ mount and use a webcam to image the moon and planets in high-res
If you want to use your DSLR at prime focus in your 10" newt to capture DSO's (at a later stage, when you're on an EQ mount), unfortunately you'll need to move your mirror up the tube.
Keep on posting and keep on asking questions!