Cote St Luc
Yes you can colonize assuming you have the ships for it. If you look at the back of the action phase cards it specifically says, that you can use any unused colony ships.
This is done during the Upkeep phase before performing your civilization upkeep.
from the rulebook page 24 wrote:
First, you may activate one or more of your remaining Colony Ships (see Colony Ships on page 8) and move Population Cubes to hexes. Contrary to the Action Phase, you may not move cubes to hexes containing enemy Ships.
Collect your Income and pay your Civilization Upkeep cost...