How many Monoliths are in each system?

There at least 3 monoliths per planet. I use my Nomad exocraft to scan for one, then fly to it with my ship, and repeat.

there are at least 20 monolith per planet sometimes, and none in others (specially I could not find any on moons) easy to know you are on a moon because its low gravity. Now I am trying to check in a new planet and so far nothing but.

1. When you check you only check on a small zone of the planet (and even so some weird times gives you the data of other planet, if there is not on the zone but there is some near planet to get data from).
2. If you check a planet sometimes just checking the nearby option gives you the same (it happen with pods and it happen with factories, sometimes it happen also with monoliths and plaques but not always).
3. once you have a mark (mark means scan for something), and if you have a mark that you want, be sure to not save it for later or just save and come back later, sometimes it goes.
4. I try not to use beacons, because a lot gives you the same coordinates, and if its already made it bugs itself and then you arrive to the place, and the mark does not go.
5. If you have too many marks, its possible that the scanner gives you nothing at all.
6. Sometimes if you use the "close" it will give you the same you know its there. (even using any of the options sometimes). that normally means there is nothing near. or nothing of that type.

What I do to solve most of this: 1 you keep heading North (or south) or some specific direction. then I search for artifacts using navigation mostly until the navigations points to the same or a repeated one (yes this way you always lost one at least). At that point I point to factories (secure), and then use the near option until it repeats again.

After that I go directly up to 3000 units up, then 10 seconds at max speed, and then land. The best result is to do this in harsh environment, because if you keep scanning around you even find ancien structures, that gives navigational data. and then you can keep doing this till you get tired.

I did this on just one planet until, the last 5 factories, give me only nanite points and nothing else. so I decided to change to other "start" type by then.