I get this question/answer a lot, but I disagree. Dark means unlit by the Sun in this case, and no semantic dodging will change that.
The Moon has a dark side, but it’s not a permanent one, any more than the Earth’s. When the Moon is new the dark side faces us; when it’s full the dark side is also the far side.
And need I mention it? Phil Plait's Bad Astronomy: Bad TV. 
I get this question/answer a lot, but I disagree. Dark means unlit by the Sun in this case, and no semantic dodging will change that.
The Moon has a dark side, but it’s not a permanent one, any more than the Earth’s. When the Moon is new the dark side faces us; when it’s full the dark side is also the far side.
And need I mention it? Phil Plait's Bad Astronomy: Bad TV.
The OP asked whether a casual amateur astronomer could see the artifacts left on the moon. I have an 8 and 1/2 inch reflector. At highest magnification, the smallest objects that I can see are craters between 10 and 20 miles across. So to answer the OP: no.
Why does it mean “unlit by the Sun in this case”? Africa is lit by the Sun, too, but “darkest Africa” means hidden Africa. I admit that the usage is pretty much restricted to Warner Bros. cartoons, but at what point does “dark side of the moon” become an idiom for the far side?
Mangetout - yes, Hubble can (and has!) provided us with images of the Moon. The problem is that it’s very difficult. Because of the speed at which the Moon is moving, Hubble has to constantly adjust to keep it in view. Thus, the images that have been taken of the Moon with Hubble aren’t at Hubble’s maximum theoretical resolution for the Moon and are “blurry.” (I’ve seen them - they’re not blurred, it’s just that they’re not as good as they could be due to the Moon’s speed. Or something. I thought they looked great.) So it can be done - indeed, I think they did it just to see if they could!
Snicks
Maybe they should put large-breasted, naked women in space. I’d watch THAT!
It’s commonly referred to as “the dark side” because it’s so evil… I mean, because it’s just easier that way. Commonality is the key here.
Or are you saying that you don’t understand what people are actually referring to when they say “dark side of the moon”? (Aside from a Pink Floyd album, of course)
Now hold on. The link provided by jab1 says that Hubble can discern features as small as 600 feet across. Maybe the Apollo lander itself is too small to see under these circumstances, but what about the disturbance in the lunar soil made by the top half of the lander blasting off? Could Hubble see this kind of evidence of Apollo?
Heck, I understated my own case. At the bottom of the page it says that in close up, Hubble can resolve features as small as 280 feet across–less than the length of a football field.
Even though all the traces would still be undisturbed in the vacuum of space, I doubt that the vast majority of the blast ring of the Lander’s blast-off would be indistinguishable from the rest of the lunar surface.
I hate to show just how little I know about all this stuff, but won’t an accumulation of dust build up on the mirror, eventually making it worthless? Or is the accumulation so slow that it doesn’t matter for any practical purposes? Or does it accumulate at all?
jr8 wrote:
If you did, you just know someone would send up a special mission to erase the C.
You could always put a little fan next to it…
I don’t know how long it takes dust to accumulate on the Moon’s surface, but I’m sure it takes a VERY long time without any atmosphere to blow it around. What dust there is comes from tiny meteors hitting the surface and pulverising the rocks and scattering the resulting debris around. The fact that the McDonald Observatory is still using the mirror* 32 years after it was placed up there shows that the rate of accumulation must be very low.
*It’s actually a collection of prisms designed to reflect light 180 degrees so that it goes back to its origin no matter the angle of illumination. IOW, the laser pulse will go right back to the observatory no matter where in the sky the Moon happens to be. Here’s a picture of it. Compare the size of the footprints around it; it’s about the size of a suitcase. (I hope to find a better photo.)
Sigh . . . Bad Astronomer, where are you?
I’m sure Munch was joking about the fan.
Yes, it has been noted that no optical telescopes can see moon artifacts. However, the other thread failed to mention the many amateur HAM radio operators who tracked the Apollo missions real-time. So while optical tracking wasn’t possible, radio tracking was. And we’re not just talking professionals, this is astronomy and radio hobbiests from around the world.
Whack-a-Mole said:
In this phrasing, the “dark = hidden” argument is wrong. Because he’d be stating a tautology. So he’s talking about sunlight - ergo, “dark side of the moon” is an error.
jr8 - CHA?
KeithB said:
I suppose someone could make that type of phrasing. That seems an antiquated and awkward turn of phrase to me, but I will accept it as a possibility. So you have to look at each case, and what the person actually says. In most cases, the word dark is referring to sunlight by the context of what they say.
LonesomePolecat said:
It’s not an issue. Remember, the moon has no atmosphere. There is very little to disturb the dust (only meteoroid impacts) and nothing to carry the dust around. It’s not like Mars where there is a thin atmosphere that can move dust and dirt. So for all practical purposes, there is no dust accumulation.
One day someone will send a lunar obiter to map the surface at high resolution like the Landsat program, and I am sure the Apollo landing areas will be photographed at high resolution. A moon rover could travel to the appropriate places take pictures as well.
It’s a reference to the comic book /cartoon [The Tick](http://www.pazsaz.com/tick1a.html#The Tick Vs. Chairface Chippendale), in which the villain Chairface Chippendale attempts to write his name on the moon with a big laser but is interrupted by the Tick, leaving the letters “CHA” clearly visible, much to the mystification of the rest of the world.
When the Tick later attempts to erase the letters from the Moon, he succeeds in eradicating the “C” but leads Omnipotus to Earth, who takes a hefty bite out of the side of the Moon.
We now return you to reality.
Considering that he TWICE mentioned sides facing towards/away from Earth, I think it was clear that he was not, in fact, referring to sunlight. Not once did he mention the lighting of the Moon (aside from the popular phrase “dark side of the Moon”).
