The resolution of my telescope is limited to d = .0004" (1/100mm).
This value corresponds to the optical resolution of coarse-grained films (range about 2000 to 3050 lines per inch (80 to 120 lines / mm), which I take for my photographs. Using the equation for optical imaging:

Object width = (object distance x image resolution)/focal length

With values
object distance = moon distance = 238,606 Miles (384,000 km)
focal length = 40" (1000 mm),
image resolution = .0004 (0.01 mm)

you can compute from picture distances to recognizable surface textures on the moon.
Using the data of my instrument (focal length = 40" or 1000 mm), I am theoretically able to recognize and picture moon details of approximately 1.86 to 3.1 Miles (3 to 5 Km) size. In fact aberrations, caused by thermal effects and air turbulence, can increase this value within a factor 5 to 10.