I think CL2 needs to know about the planet - I may have coded everything with the assumption that the planet you want to land on or fly around has had a scan performed and hence the data loaded into CL2.
It is an app with Exploration in mind after all
If this is a planet in one of the 'known' systems - i.e. the ship already had all the scan data (as with a lot of bubble systems), and if that system has a Nav Beacon, you can go to the Nav Beacon and scan it. Note that having a DSS fitted whilst doing so is recommended. Captain's Log will then receive all the data about all the bodies within that system, exactly as if you have DSS scanned them yourself.
Definitely in the bubble known system, Shinrarta, so I had all the data. I assumed that CL would pick it up from the journals and know I would be on approach when in orbital and would take my coordinates.
I know its more for exploration, which I am using it for, but the other uses for it on known planets because of the navigation ability would a boon. I am using it on my other account, but was dying to try out the Chieftain and of course, that meant landing on a new looking planet to compare how it looked before.
So scanning the Beacon would be the only option for places that are already know?