my players found a star chart, or I let them find one.

What have other people done with this?

I can't out if I just make up a new planet or use an existing one.

the map is pre clone wars so I'm considering making it point to a planet not in the official records now used as a hideout for smugglers.

I'm also giving the option to the crew of selling the chart to the Spacelane Bureau or guild.

or maybe one of their criminal contacts.

The numbers of options are almost infinite.

Maybe it's a "backdoor" into a known system? That would make it worth a lot to many people.

Maybe it's a route to a lost old republic colony? If so the players can go investigate, maybe they'll find a happy little colony ready for trade, or maybe a ghost town with nothing but dust, ashes, and "Roanoke" carved into the tree int he middle of town.

Maybe it's even older, a route to a hidden Sith sanctuary world? After a few thousand years things got a little mixed up, the majority non-force sensitive slave population long having liberated themselves, but also integrating the tale into their religion. When the players land they are received as divine messengers, The Great Party of Buwana, who have come to judge those worthy to join the great lords of the Stars as the Prophecy has foretold. (Note: have all the priests, and most others end almost every sentence spoken to the PCs with "as the Prophecy has foretold")

Maybe it's so old the players essentially need to re-chart the route to accommodate for galactic drift? Who knows what else has drifted in over the centuries?

Maybe it leads to what is now a secret imperial staging area?

There's lots of fun options...

The chart data is so far out of date, or a forgery, and the first time they take it to anyone with a decent knowledge of such things they get laughed out of the office. Maybe it hides something else, like completely unrelated data? Maybe some nerdy Bothan teenager cracked the holonet code, and the cipher key is hidden within the chart data?

Maybe it just says "Be sure to drink more Ovaltine."

Or leads to a the treasure of "One eyed Billy".

that sounds like it would make a great treasure map. If they decide to study it and investigate areas they might be able to find ruins, abandoned outposts and other stuff that could help supply them. While the charts themselves probably wont help much might be a few things on there that could help with the party wealth. Could be a one time benefit or an item that can continue to provide them with such adventures

could easily be a lead in to Beyond the Rim.