GTS Celebrity Constellation is a Millennium class cruise ship of Celebrity Cruises. She is the co-flagship of the Celebrity fleet, along with Century-class ship Century. She was originally named Constellation, but renamed in May 2007. Her three sister ships are the Celebrity Infinity, Summit, and Millennium.
She was built at the Chantiers de l'Atlantique shipyard in St. Nazaire, France. The ship boasts a COGAS power plant of gas turbines and a steam turbine providing up to 60 Megawatts for the electric systems and two 19 MW Rolls-Royce/Alstom MerMaid azimuth thrusters for propulsion. In 2007, she was refitted with the addition of a diesel engine as a fuel-saving measure. The ship can run on any combination of the gas turbines or diesel. In port, she generates electrical power from the diesel.
Constellation consistently receives top honors from Condé Nast's readers survey, and is currently ranked by readers as the best large cruise ship. During the summer period the ship sails in Northern Europe. Since her delivery the ship sails to the Baltic Sea between May and August. In June 2010 and July 2011 the ship will also sail to the Norwegian Fjords up to the North Cape. The rest of the season the ship sails to the Mediterranean (fall) and the Caribbean (winter).