stellatography

It lets you see planets around stars on your mini-map. I usually have the planets turned off since they clutter the map, so I don't recommend researching the tech until you need Sensors--but that's what it does, all the same.

Actually it's good to have when you are first exploring and colonizing... there is nothing worse sending your colony ship to a system with no planets, when you could have gone the other way where there are 4 planets in the system. It's really only useful right at the very beginning with the rush of colonizing, though.

Just MHO!

That's true, I've turned it on for that in a couple games. I usually play with planets at a minimum of Common, though, so I often just assume--correctly--that all stars will have planets.

It depends on the galaxy settings. Depending on how you set it up, most stars could have planets, habitable or otherwise. Stellar cartography really isn't useful in that situation because it doesn't show which ones are useable.

If it's set to rare or uncommon or something, then it becomes more important, since more stars would have no planets at all and you don't want to waste time exploring those.

Thanks heaps.