Scanner Upgrades

Hello all,

I used to play NMS back when it first launched and put it down, until I saw the Worlds update, which has drawn me back in. I have seen from a lot of people that scanner upgrades are great way to earn some credits while I focus on exploring the crazy new environments. This is where I have a stupid question: I have tried looking for these at a few different places and was wondering where I should be looking. All of the upgrades I find are pretty measly and don’t make much of a difference. Where can I find high quality scanner upgrades?