What. Things come down because of gravity, not because the pretense of an atmosphere.

Presumably the stuff required to move stuff to make the scope will disturb at least some sand

US astronauts found that static charge made the regolith stick to everything that came near it. Basically anything that moved across the surface got quickly coated. And because there is no weathering on the moon, the particles could be extremely small and sharp, which made it difficult to exclude or expel them. Apollo suits at the Smithsonian are still gray with embedded regolith. Conservators try to minimize flexing as the embedded sharp particles chew up the fabric fibers over time.