You have to scout 0.5 systems, look for athanors on overview/dscan, warp to them to find a belt. Otherwise talk to athanor owners and negotiate access, you might get advance warning of when the belt is due. Some corps run public access and publish frack times on the structure bio or in the structure name.
Don’t forget Lowsec, nice moon goo sometimes, ripe for raiding and fun especially if you can put together a small fleet
Some lowsec corps will do access deals. You can get access to moon mining in Providence (Null) and the better ores usually for a 10% or thereabouts ore tax.