Go to Venus were the vex battle with the fallen. They continuously Spawn and battle one another. And for the materials here is my trick. If you pick up a node that near a different (for example bordering The divide and skyreach). You can immediately run to that loading screen and run back to the node and that node will be refreshed until the node starts to turn red and that means your time to farm that single node has ran out. Sorry if it's hard to understand if you have questions message me I farm mine in under 2 hours