Coordinates, and Earth-based telescopes should be able to do it.
The moon is too far away, and the landing modules too small, to show up with usable resolution on any telescope currently in existence.
That mankind has planted artifacts on the moon, however, may be proven with the aid of properly-designed terrestrial equipment since the astronauts planted corner reflector modules at the landing sights. Point a good laser at a landing sight and it will yield a measurable reflection. Point it elsewhere at the moon and it won't.
I met him at a convention once and he told us that he landed on the moon. Is that good enough for you? (not made up)
"...Armstrong is an engineer and I believe he is an honorable man. I for one would like to hear it all from him...."
I am currently reading an authorized bio of him, "First Man-the life of Neil Armstrong". Good book. If Neil, Buzz, and the other ten guys that walked on the moon sadi they did, I'll believe them. This cannot be the Mother of all Hoaxes.