Astrophotography is an amazing venture, and is easily achieved but their are some physical limitations you need to keep in mind.
You can photograph the moon at any location you want. Even though it is visible at night, it is still reflecting the sun's light. You will need to close down your aperture, increase your shutter speed and keep you ISO to about 100. Now the longer your focal length the better, you'll capture more details and need to crop less. And speaking of cropping, higher megapixels sensors can give you more leeway while cropping. Now the latter is not a must, but it is an advantage. The last moon shots I got I was at 400mm, ISO 100, f/5.6 and shutter speed at 1/500th.
As for starts, and could be extended to other astral bodies, you need to be in an area that has the least amount of light pollution. There are websites to help you determine those areas. Otherwise you'd have to deal with the extra light coming into your sensor. There are 2 rules for choosing the shutter speed, I suggest you experiment and see which one gives you the best result. As for the aperture, you'd need a fast lens, preferably f/1.4. You can increase your ISO if needed while trying to be careful with how much noise you are willing to tolerate. The shot I took was auto 8s, ISO 400 and f/1.8. And you want the moon to be a new moon.
I used the 14mm f/1.8 GM lens for the stars image, while the 100-400mm GM for the moon image. And you might consider sensor modification, it basically removes the filter from the sensor giving it the ability to capture IS and UV rays.
