I've read that I should be able to see all the collectables with lvl 3 exploration. I don't know if this is working. It also says I should "refresh the map" every 30 seconds. I seem to be finding collectables a bit more often, but how do I refresh the map?

That tech level allows you to see collectibles on the map, but they are not updated if you just let it sit on that screen: if a new collectible appears while you're on Map, it will not be displayed. To "refresh" it, simply go back to the main game screen and select Map again.

Thanks! Works now!

Quickest way is to go the the map, and then hold down the "M" key while clicking repeatedly on "Done".